DEPARTMENT OF CIVIL ENGINEERINGBAYERO UNIVERSITY KANO

NIGERIA PRESENTATION

BYDAUDU ALEX TASHILANI

SPS15MCE00017email - lexylinksyahoocom

MENG ndash CIVIL ENGINEERING (HIGHWAY AND TRANSPORTATION)

ONREVIEW ON ROAD NETWORK

COURSE LECTURER DR HASHIM M ALHASSAN

INTRODUCTION Roads are the lifeblood of Nigeria trade and social utility

Despite the increasing focus on the use of other modalities like railway shipping and all kinds of public transport roads carryrsquos the majority of land freight (bulk) transport and passenger traffic Keeping this traffic rolling is the main concern for road authorities Building new roads or expanding square meters of asphalt might seem to be the obvious way to do this

Transportation and property are important in physical and economic development of towns and cities all over the world Property and land values tend to increase in areas with expanding transportation networks and increase less rapidly in areas without such improvements Rapid and continued rise in housing and land prices are expected in cities with transportation improvements and rapid economic and population growth (Goldberg 1970)

Road networks are observed in terms of its components of accessibility connectivity traffic density level of service compactness and density of particular roads Level of service is a measure by which the quality of service on transportation devices or infrastructure is determined Developments of various transportation modes have become pivotal to physical and economic developments Such modes include railways ropeways and cableways pipelines inland waterways sea air and roads (Said and Shah 2008)

As rivers and mountains naturally reclaim the geographical composition of the continents so ground transportation systems dominate the physical planning of landscapes and cities These man-made systemsbarriers offer freedom of movement to people and goods in the society

ROAD NETWORK Road network literarily refers to the framework of routes within a

system of location According to Rodrique et al (2006) transportation network are of various types of links between points along which movement can take place Rao and Jayasree (2010) expressed that a proper skeleton of road network creates a promotional impact of land use activity in the urban centers Rodrique et al (2006) categorized road network structure into two based on the accessibility they provide The centripetal network favors a limited number of locations The centrifugal network on the other hand does not convey any specific network connection advantages The arrangement and connectivity of transport network is known as its typology Road network can also be classified based on their typological attributes Rodrique identified several criteria for such classification among which are orientation and extent mode and terminals type of traffic volume and direction or pattern of network

NETWORK DESIGN METHOD Road network patterns can affect traffic performance travel behavior

and traffic safety Thus a deep understanding of the properties of different network patterns can provide useful guidance for design and improvement of road systems

bull Designing successful transportation networks requires more than the application of the functional classification In order to assist stakeholders in the design process a step-by-step design process is setup

bull It is not a blueprint that tells stakeholders exactly what to do merely a framework within which they make decisions

bull The stakeholders get to make the designs but the method brings structure to the design process by indicating which decisions need to be made at what point in the process

bull It is based on a number of important characteristics which are listed in random order in Figure1

FIGURE 1 Important Network Characteristics

Structure then Elementsbull First a perspective on the complete structure of the network

must be developed such as which cities must be connected by the network which scale levels are distinguished etc

bull Only then can a decision be made about the elements (road sections junctions and routes alignment) In practice problems are usually solved at the element level bottleneck by bottleneck

Higher Scale Level then the Lower Scale Levelbull Networks for every scale level are designed independently

following a top-down approach from the higher to the lower scale level with a feedback loop bottom-up

bull Each network is designed to meet its functional requirements optimally In order to achieve coherence between networks of different scale levels access points of higher scale level are automatically included in the lower scale level

Collective Networks then the Individual Networksbull Access to collective transport systems is much more cumbersome than access

to individual transport and therefore the situation of the access points of the collective system (public transport stops) requires more careful consideration than the situation of access points of the individual networks (eg highway and freeway entry points) This is because in the case of collective transport unlike individual transport access and egress by lower-level transport either requires physical transfers from and to other modes or takes place on foot Therefore important public transport nodes are preferably situated within a short distance of main origin and destination points When integrating collective and individual networks (per scale level) the collective transport system receives priority in the design for instance when it comes to the situation of intermodal transfer points

Ideal then Existingbull First an ideal network is designed ignoring the existing network Subsequently

this ideal structure is confronted with the existing situation The actions that need to be taken to change the existing situation into the ideal situation can then be prioritized This way improvements in the existing networks will be coherent the ideal structure serves as along- term perspective

Quality then Capacity The desired level-of- service or quality of the connections in the network needs to be defined

clearly Quality concerns characteristics such as speed reliability and comfort but also pricing policies and traffic management strategies that are applied to the network An acceptable volume-capacity ratio (capacity) is a prerequisite but capacity should be considered separately from the desired quality

Access Points then the Network A transport network serves to connect access points Therefore it is logical to define first which

access points should be connected and then design the connections between these points (the network) In practice it is often done the other way around A well-known example in Europe is the discussion about which cities should get high-speed train stations on the line from Amsterdam to Paris Whether or not the train was going to stop in The Hague a decision that should have been made before a route was chosen became dependent on the choice for one route or the other

Function then Layout and Technique Before the layout of the various components of the networks (access points links and junctions)

is defined it must be clear what the function of this component is By gearing the layout to the functional requirements it is more likely that this road will be used in accordance with the objectives set it As a consequence changing the function of a road (eg from national to regional) can lead to changing the layout (eg from highway to regional main road) The same principles apply to collective networks For example the choice between bus and rail should depend on the function in some cases both techniques can meet the requirements

NETWORK CHARACTERISTICS Road networks can be defined as series of nodes and links which represents spatial

locations and connections exhibiting geometric variations and topological variations A network can be a set of linear features through which resources flow Nodes (the end points of lines) are used as origins and destinations and links (lines) travers from one node to the other Nodes can have properties but in network analysis we are usually more concerned with the characteristics of the links (Laurini and Thompson 1992) These include

bull lengthbull directionbull connectivity (lines must connect at least two points) andbull pattern There are four main types of classification of network the classification of networks was

discussed by Laurini and Thompson (1992) They suggested the four main types which include

bull oriented with loopsbull unoriented with loopsbull unorientedbull oriented A classification of networks (adapted from Laurini amp Thompson 1992)

Roads can either be oriented or not (ie one way or two way) and usually contain loops For example Rivers flowing in one direction only downhill are best represented by an oriented network Trains usually travel in both directions between stations On smaller lines with only one track the railway network is unoreinted Elsewhere in the network there are lines designated for travel in one direction only for reasons of safety Two-track networks are represented by a pair of oriented links in a network and so either an unoriented or unoriented network with loops may be suitable here

ROAD NETWORK HIERACHY A road hierarchy is a means of defining each roadway in terms of its function such

that appropriate objectives for that roadway can be set and appropriate design criteria can be implemented The road hierarchy can then form the basis of ongoing planning and system management aimed at reducing the mixing of incompatible functions

A road hierarchy differentiates between roads by function Roads at the top of road hierarchy are generally arterial routes that cater for through traffic and often have high traffic volume and operate at high speeds Roads at the lower end of a road hierarchy tend to have a local access function and may have lower volume or speed environments The use of road hierarchy contributes to road safety by reducing turning movements onto and from high volume high speed roads and can also aid the planning of safe and efficient bus cycling and walking routes

The basic road hierarchy comprises freeways arterials collectors and local roads

Freeways These roads provide largely uninterrupted travel often using partial

or full access control and are designed for high speeds Some freeways have collectordistributor lanes (also known as local lanes) which further reduce the number of access ramps that directly interface with the freeway rather the freeway periodically interfaces with these parallel roadways which themselves have multiple on and off-ramps These allow the freeway to operate with less friction at an even higher speed and with higher flow

Arterialsbull Arterials are major roads that are expected to carry large volumes of

traffic Arterials are often divided into major and minor arterials and rural and urban arterials Such roads are usually classified as arterials Frontage roads are often used to reduce the conflict between the high-speed nature of an arterial and property access concerns

INTRODUCTION Roads are the lifeblood of Nigeria trade and social utility

Despite the increasing focus on the use of other modalities like railway shipping and all kinds of public transport roads carryrsquos the majority of land freight (bulk) transport and passenger traffic Keeping this traffic rolling is the main concern for road authorities Building new roads or expanding square meters of asphalt might seem to be the obvious way to do this

Transportation and property are important in physical and economic development of towns and cities all over the world Property and land values tend to increase in areas with expanding transportation networks and increase less rapidly in areas without such improvements Rapid and continued rise in housing and land prices are expected in cities with transportation improvements and rapid economic and population growth (Goldberg 1970)

Road networks are observed in terms of its components of accessibility connectivity traffic density level of service compactness and density of particular roads Level of service is a measure by which the quality of service on transportation devices or infrastructure is determined Developments of various transportation modes have become pivotal to physical and economic developments Such modes include railways ropeways and cableways pipelines inland waterways sea air and roads (Said and Shah 2008)

As rivers and mountains naturally reclaim the geographical composition of the continents so ground transportation systems dominate the physical planning of landscapes and cities These man-made systemsbarriers offer freedom of movement to people and goods in the society

ROAD NETWORK Road network literarily refers to the framework of routes within a

system of location According to Rodrique et al (2006) transportation network are of various types of links between points along which movement can take place Rao and Jayasree (2010) expressed that a proper skeleton of road network creates a promotional impact of land use activity in the urban centers Rodrique et al (2006) categorized road network structure into two based on the accessibility they provide The centripetal network favors a limited number of locations The centrifugal network on the other hand does not convey any specific network connection advantages The arrangement and connectivity of transport network is known as its typology Road network can also be classified based on their typological attributes Rodrique identified several criteria for such classification among which are orientation and extent mode and terminals type of traffic volume and direction or pattern of network

NETWORK DESIGN METHOD Road network patterns can affect traffic performance travel behavior

and traffic safety Thus a deep understanding of the properties of different network patterns can provide useful guidance for design and improvement of road systems

bull Designing successful transportation networks requires more than the application of the functional classification In order to assist stakeholders in the design process a step-by-step design process is setup

bull It is not a blueprint that tells stakeholders exactly what to do merely a framework within which they make decisions

bull The stakeholders get to make the designs but the method brings structure to the design process by indicating which decisions need to be made at what point in the process

bull It is based on a number of important characteristics which are listed in random order in Figure1

FIGURE 1 Important Network Characteristics

Structure then Elementsbull First a perspective on the complete structure of the network

must be developed such as which cities must be connected by the network which scale levels are distinguished etc

bull Only then can a decision be made about the elements (road sections junctions and routes alignment) In practice problems are usually solved at the element level bottleneck by bottleneck

Higher Scale Level then the Lower Scale Levelbull Networks for every scale level are designed independently

following a top-down approach from the higher to the lower scale level with a feedback loop bottom-up

bull Each network is designed to meet its functional requirements optimally In order to achieve coherence between networks of different scale levels access points of higher scale level are automatically included in the lower scale level

Collective Networks then the Individual Networksbull Access to collective transport systems is much more cumbersome than access

to individual transport and therefore the situation of the access points of the collective system (public transport stops) requires more careful consideration than the situation of access points of the individual networks (eg highway and freeway entry points) This is because in the case of collective transport unlike individual transport access and egress by lower-level transport either requires physical transfers from and to other modes or takes place on foot Therefore important public transport nodes are preferably situated within a short distance of main origin and destination points When integrating collective and individual networks (per scale level) the collective transport system receives priority in the design for instance when it comes to the situation of intermodal transfer points

Ideal then Existingbull First an ideal network is designed ignoring the existing network Subsequently

this ideal structure is confronted with the existing situation The actions that need to be taken to change the existing situation into the ideal situation can then be prioritized This way improvements in the existing networks will be coherent the ideal structure serves as along- term perspective

Quality then Capacity The desired level-of- service or quality of the connections in the network needs to be defined

clearly Quality concerns characteristics such as speed reliability and comfort but also pricing policies and traffic management strategies that are applied to the network An acceptable volume-capacity ratio (capacity) is a prerequisite but capacity should be considered separately from the desired quality

Access Points then the Network A transport network serves to connect access points Therefore it is logical to define first which

access points should be connected and then design the connections between these points (the network) In practice it is often done the other way around A well-known example in Europe is the discussion about which cities should get high-speed train stations on the line from Amsterdam to Paris Whether or not the train was going to stop in The Hague a decision that should have been made before a route was chosen became dependent on the choice for one route or the other

Function then Layout and Technique Before the layout of the various components of the networks (access points links and junctions)

is defined it must be clear what the function of this component is By gearing the layout to the functional requirements it is more likely that this road will be used in accordance with the objectives set it As a consequence changing the function of a road (eg from national to regional) can lead to changing the layout (eg from highway to regional main road) The same principles apply to collective networks For example the choice between bus and rail should depend on the function in some cases both techniques can meet the requirements

NETWORK CHARACTERISTICS Road networks can be defined as series of nodes and links which represents spatial

locations and connections exhibiting geometric variations and topological variations A network can be a set of linear features through which resources flow Nodes (the end points of lines) are used as origins and destinations and links (lines) travers from one node to the other Nodes can have properties but in network analysis we are usually more concerned with the characteristics of the links (Laurini and Thompson 1992) These include

bull lengthbull directionbull connectivity (lines must connect at least two points) andbull pattern There are four main types of classification of network the classification of networks was

discussed by Laurini and Thompson (1992) They suggested the four main types which include

bull oriented with loopsbull unoriented with loopsbull unorientedbull oriented A classification of networks (adapted from Laurini amp Thompson 1992)

Roads can either be oriented or not (ie one way or two way) and usually contain loops For example Rivers flowing in one direction only downhill are best represented by an oriented network Trains usually travel in both directions between stations On smaller lines with only one track the railway network is unoreinted Elsewhere in the network there are lines designated for travel in one direction only for reasons of safety Two-track networks are represented by a pair of oriented links in a network and so either an unoriented or unoriented network with loops may be suitable here

ROAD NETWORK HIERACHY A road hierarchy is a means of defining each roadway in terms of its function such

that appropriate objectives for that roadway can be set and appropriate design criteria can be implemented The road hierarchy can then form the basis of ongoing planning and system management aimed at reducing the mixing of incompatible functions

A road hierarchy differentiates between roads by function Roads at the top of road hierarchy are generally arterial routes that cater for through traffic and often have high traffic volume and operate at high speeds Roads at the lower end of a road hierarchy tend to have a local access function and may have lower volume or speed environments The use of road hierarchy contributes to road safety by reducing turning movements onto and from high volume high speed roads and can also aid the planning of safe and efficient bus cycling and walking routes

The basic road hierarchy comprises freeways arterials collectors and local roads

Freeways These roads provide largely uninterrupted travel often using partial

or full access control and are designed for high speeds Some freeways have collectordistributor lanes (also known as local lanes) which further reduce the number of access ramps that directly interface with the freeway rather the freeway periodically interfaces with these parallel roadways which themselves have multiple on and off-ramps These allow the freeway to operate with less friction at an even higher speed and with higher flow

Arterialsbull Arterials are major roads that are expected to carry large volumes of

traffic Arterials are often divided into major and minor arterials and rural and urban arterials Such roads are usually classified as arterials Frontage roads are often used to reduce the conflict between the high-speed nature of an arterial and property access concerns

Road networks are observed in terms of its components of accessibility connectivity traffic density level of service compactness and density of particular roads Level of service is a measure by which the quality of service on transportation devices or infrastructure is determined Developments of various transportation modes have become pivotal to physical and economic developments Such modes include railways ropeways and cableways pipelines inland waterways sea air and roads (Said and Shah 2008)

As rivers and mountains naturally reclaim the geographical composition of the continents so ground transportation systems dominate the physical planning of landscapes and cities These man-made systemsbarriers offer freedom of movement to people and goods in the society

ROAD NETWORK Road network literarily refers to the framework of routes within a

system of location According to Rodrique et al (2006) transportation network are of various types of links between points along which movement can take place Rao and Jayasree (2010) expressed that a proper skeleton of road network creates a promotional impact of land use activity in the urban centers Rodrique et al (2006) categorized road network structure into two based on the accessibility they provide The centripetal network favors a limited number of locations The centrifugal network on the other hand does not convey any specific network connection advantages The arrangement and connectivity of transport network is known as its typology Road network can also be classified based on their typological attributes Rodrique identified several criteria for such classification among which are orientation and extent mode and terminals type of traffic volume and direction or pattern of network

NETWORK DESIGN METHOD Road network patterns can affect traffic performance travel behavior

and traffic safety Thus a deep understanding of the properties of different network patterns can provide useful guidance for design and improvement of road systems

bull Designing successful transportation networks requires more than the application of the functional classification In order to assist stakeholders in the design process a step-by-step design process is setup

bull It is not a blueprint that tells stakeholders exactly what to do merely a framework within which they make decisions

bull The stakeholders get to make the designs but the method brings structure to the design process by indicating which decisions need to be made at what point in the process

bull It is based on a number of important characteristics which are listed in random order in Figure1

FIGURE 1 Important Network Characteristics

Structure then Elementsbull First a perspective on the complete structure of the network

must be developed such as which cities must be connected by the network which scale levels are distinguished etc

bull Only then can a decision be made about the elements (road sections junctions and routes alignment) In practice problems are usually solved at the element level bottleneck by bottleneck

Higher Scale Level then the Lower Scale Levelbull Networks for every scale level are designed independently

following a top-down approach from the higher to the lower scale level with a feedback loop bottom-up

bull Each network is designed to meet its functional requirements optimally In order to achieve coherence between networks of different scale levels access points of higher scale level are automatically included in the lower scale level

Collective Networks then the Individual Networksbull Access to collective transport systems is much more cumbersome than access

to individual transport and therefore the situation of the access points of the collective system (public transport stops) requires more careful consideration than the situation of access points of the individual networks (eg highway and freeway entry points) This is because in the case of collective transport unlike individual transport access and egress by lower-level transport either requires physical transfers from and to other modes or takes place on foot Therefore important public transport nodes are preferably situated within a short distance of main origin and destination points When integrating collective and individual networks (per scale level) the collective transport system receives priority in the design for instance when it comes to the situation of intermodal transfer points

Ideal then Existingbull First an ideal network is designed ignoring the existing network Subsequently

this ideal structure is confronted with the existing situation The actions that need to be taken to change the existing situation into the ideal situation can then be prioritized This way improvements in the existing networks will be coherent the ideal structure serves as along- term perspective

Quality then Capacity The desired level-of- service or quality of the connections in the network needs to be defined

clearly Quality concerns characteristics such as speed reliability and comfort but also pricing policies and traffic management strategies that are applied to the network An acceptable volume-capacity ratio (capacity) is a prerequisite but capacity should be considered separately from the desired quality

Access Points then the Network A transport network serves to connect access points Therefore it is logical to define first which

access points should be connected and then design the connections between these points (the network) In practice it is often done the other way around A well-known example in Europe is the discussion about which cities should get high-speed train stations on the line from Amsterdam to Paris Whether or not the train was going to stop in The Hague a decision that should have been made before a route was chosen became dependent on the choice for one route or the other

Function then Layout and Technique Before the layout of the various components of the networks (access points links and junctions)

is defined it must be clear what the function of this component is By gearing the layout to the functional requirements it is more likely that this road will be used in accordance with the objectives set it As a consequence changing the function of a road (eg from national to regional) can lead to changing the layout (eg from highway to regional main road) The same principles apply to collective networks For example the choice between bus and rail should depend on the function in some cases both techniques can meet the requirements

NETWORK CHARACTERISTICS Road networks can be defined as series of nodes and links which represents spatial

locations and connections exhibiting geometric variations and topological variations A network can be a set of linear features through which resources flow Nodes (the end points of lines) are used as origins and destinations and links (lines) travers from one node to the other Nodes can have properties but in network analysis we are usually more concerned with the characteristics of the links (Laurini and Thompson 1992) These include

bull lengthbull directionbull connectivity (lines must connect at least two points) andbull pattern There are four main types of classification of network the classification of networks was

discussed by Laurini and Thompson (1992) They suggested the four main types which include

bull oriented with loopsbull unoriented with loopsbull unorientedbull oriented A classification of networks (adapted from Laurini amp Thompson 1992)

Roads can either be oriented or not (ie one way or two way) and usually contain loops For example Rivers flowing in one direction only downhill are best represented by an oriented network Trains usually travel in both directions between stations On smaller lines with only one track the railway network is unoreinted Elsewhere in the network there are lines designated for travel in one direction only for reasons of safety Two-track networks are represented by a pair of oriented links in a network and so either an unoriented or unoriented network with loops may be suitable here

ROAD NETWORK HIERACHY A road hierarchy is a means of defining each roadway in terms of its function such

that appropriate objectives for that roadway can be set and appropriate design criteria can be implemented The road hierarchy can then form the basis of ongoing planning and system management aimed at reducing the mixing of incompatible functions

A road hierarchy differentiates between roads by function Roads at the top of road hierarchy are generally arterial routes that cater for through traffic and often have high traffic volume and operate at high speeds Roads at the lower end of a road hierarchy tend to have a local access function and may have lower volume or speed environments The use of road hierarchy contributes to road safety by reducing turning movements onto and from high volume high speed roads and can also aid the planning of safe and efficient bus cycling and walking routes

The basic road hierarchy comprises freeways arterials collectors and local roads

Freeways These roads provide largely uninterrupted travel often using partial

or full access control and are designed for high speeds Some freeways have collectordistributor lanes (also known as local lanes) which further reduce the number of access ramps that directly interface with the freeway rather the freeway periodically interfaces with these parallel roadways which themselves have multiple on and off-ramps These allow the freeway to operate with less friction at an even higher speed and with higher flow

Arterialsbull Arterials are major roads that are expected to carry large volumes of

traffic Arterials are often divided into major and minor arterials and rural and urban arterials Such roads are usually classified as arterials Frontage roads are often used to reduce the conflict between the high-speed nature of an arterial and property access concerns

ROAD NETWORK Road network literarily refers to the framework of routes within a

system of location According to Rodrique et al (2006) transportation network are of various types of links between points along which movement can take place Rao and Jayasree (2010) expressed that a proper skeleton of road network creates a promotional impact of land use activity in the urban centers Rodrique et al (2006) categorized road network structure into two based on the accessibility they provide The centripetal network favors a limited number of locations The centrifugal network on the other hand does not convey any specific network connection advantages The arrangement and connectivity of transport network is known as its typology Road network can also be classified based on their typological attributes Rodrique identified several criteria for such classification among which are orientation and extent mode and terminals type of traffic volume and direction or pattern of network

NETWORK DESIGN METHOD Road network patterns can affect traffic performance travel behavior

and traffic safety Thus a deep understanding of the properties of different network patterns can provide useful guidance for design and improvement of road systems

bull Designing successful transportation networks requires more than the application of the functional classification In order to assist stakeholders in the design process a step-by-step design process is setup

bull It is not a blueprint that tells stakeholders exactly what to do merely a framework within which they make decisions

bull The stakeholders get to make the designs but the method brings structure to the design process by indicating which decisions need to be made at what point in the process

bull It is based on a number of important characteristics which are listed in random order in Figure1

FIGURE 1 Important Network Characteristics

Structure then Elementsbull First a perspective on the complete structure of the network

must be developed such as which cities must be connected by the network which scale levels are distinguished etc

bull Only then can a decision be made about the elements (road sections junctions and routes alignment) In practice problems are usually solved at the element level bottleneck by bottleneck

Higher Scale Level then the Lower Scale Levelbull Networks for every scale level are designed independently

following a top-down approach from the higher to the lower scale level with a feedback loop bottom-up

bull Each network is designed to meet its functional requirements optimally In order to achieve coherence between networks of different scale levels access points of higher scale level are automatically included in the lower scale level

Collective Networks then the Individual Networksbull Access to collective transport systems is much more cumbersome than access

to individual transport and therefore the situation of the access points of the collective system (public transport stops) requires more careful consideration than the situation of access points of the individual networks (eg highway and freeway entry points) This is because in the case of collective transport unlike individual transport access and egress by lower-level transport either requires physical transfers from and to other modes or takes place on foot Therefore important public transport nodes are preferably situated within a short distance of main origin and destination points When integrating collective and individual networks (per scale level) the collective transport system receives priority in the design for instance when it comes to the situation of intermodal transfer points

Ideal then Existingbull First an ideal network is designed ignoring the existing network Subsequently

this ideal structure is confronted with the existing situation The actions that need to be taken to change the existing situation into the ideal situation can then be prioritized This way improvements in the existing networks will be coherent the ideal structure serves as along- term perspective

Quality then Capacity The desired level-of- service or quality of the connections in the network needs to be defined

clearly Quality concerns characteristics such as speed reliability and comfort but also pricing policies and traffic management strategies that are applied to the network An acceptable volume-capacity ratio (capacity) is a prerequisite but capacity should be considered separately from the desired quality

Access Points then the Network A transport network serves to connect access points Therefore it is logical to define first which

access points should be connected and then design the connections between these points (the network) In practice it is often done the other way around A well-known example in Europe is the discussion about which cities should get high-speed train stations on the line from Amsterdam to Paris Whether or not the train was going to stop in The Hague a decision that should have been made before a route was chosen became dependent on the choice for one route or the other

Function then Layout and Technique Before the layout of the various components of the networks (access points links and junctions)

is defined it must be clear what the function of this component is By gearing the layout to the functional requirements it is more likely that this road will be used in accordance with the objectives set it As a consequence changing the function of a road (eg from national to regional) can lead to changing the layout (eg from highway to regional main road) The same principles apply to collective networks For example the choice between bus and rail should depend on the function in some cases both techniques can meet the requirements

NETWORK CHARACTERISTICS Road networks can be defined as series of nodes and links which represents spatial

locations and connections exhibiting geometric variations and topological variations A network can be a set of linear features through which resources flow Nodes (the end points of lines) are used as origins and destinations and links (lines) travers from one node to the other Nodes can have properties but in network analysis we are usually more concerned with the characteristics of the links (Laurini and Thompson 1992) These include

bull lengthbull directionbull connectivity (lines must connect at least two points) andbull pattern There are four main types of classification of network the classification of networks was

discussed by Laurini and Thompson (1992) They suggested the four main types which include

bull oriented with loopsbull unoriented with loopsbull unorientedbull oriented A classification of networks (adapted from Laurini amp Thompson 1992)

Roads can either be oriented or not (ie one way or two way) and usually contain loops For example Rivers flowing in one direction only downhill are best represented by an oriented network Trains usually travel in both directions between stations On smaller lines with only one track the railway network is unoreinted Elsewhere in the network there are lines designated for travel in one direction only for reasons of safety Two-track networks are represented by a pair of oriented links in a network and so either an unoriented or unoriented network with loops may be suitable here

ROAD NETWORK HIERACHY A road hierarchy is a means of defining each roadway in terms of its function such

that appropriate objectives for that roadway can be set and appropriate design criteria can be implemented The road hierarchy can then form the basis of ongoing planning and system management aimed at reducing the mixing of incompatible functions

A road hierarchy differentiates between roads by function Roads at the top of road hierarchy are generally arterial routes that cater for through traffic and often have high traffic volume and operate at high speeds Roads at the lower end of a road hierarchy tend to have a local access function and may have lower volume or speed environments The use of road hierarchy contributes to road safety by reducing turning movements onto and from high volume high speed roads and can also aid the planning of safe and efficient bus cycling and walking routes

The basic road hierarchy comprises freeways arterials collectors and local roads

Freeways These roads provide largely uninterrupted travel often using partial

or full access control and are designed for high speeds Some freeways have collectordistributor lanes (also known as local lanes) which further reduce the number of access ramps that directly interface with the freeway rather the freeway periodically interfaces with these parallel roadways which themselves have multiple on and off-ramps These allow the freeway to operate with less friction at an even higher speed and with higher flow

Arterialsbull Arterials are major roads that are expected to carry large volumes of

traffic Arterials are often divided into major and minor arterials and rural and urban arterials Such roads are usually classified as arterials Frontage roads are often used to reduce the conflict between the high-speed nature of an arterial and property access concerns

NETWORK DESIGN METHOD Road network patterns can affect traffic performance travel behavior

and traffic safety Thus a deep understanding of the properties of different network patterns can provide useful guidance for design and improvement of road systems

bull Designing successful transportation networks requires more than the application of the functional classification In order to assist stakeholders in the design process a step-by-step design process is setup

bull It is not a blueprint that tells stakeholders exactly what to do merely a framework within which they make decisions

bull The stakeholders get to make the designs but the method brings structure to the design process by indicating which decisions need to be made at what point in the process

bull It is based on a number of important characteristics which are listed in random order in Figure1

FIGURE 1 Important Network Characteristics

Structure then Elementsbull First a perspective on the complete structure of the network

must be developed such as which cities must be connected by the network which scale levels are distinguished etc

bull Only then can a decision be made about the elements (road sections junctions and routes alignment) In practice problems are usually solved at the element level bottleneck by bottleneck

Higher Scale Level then the Lower Scale Levelbull Networks for every scale level are designed independently

following a top-down approach from the higher to the lower scale level with a feedback loop bottom-up

bull Each network is designed to meet its functional requirements optimally In order to achieve coherence between networks of different scale levels access points of higher scale level are automatically included in the lower scale level

Collective Networks then the Individual Networksbull Access to collective transport systems is much more cumbersome than access

to individual transport and therefore the situation of the access points of the collective system (public transport stops) requires more careful consideration than the situation of access points of the individual networks (eg highway and freeway entry points) This is because in the case of collective transport unlike individual transport access and egress by lower-level transport either requires physical transfers from and to other modes or takes place on foot Therefore important public transport nodes are preferably situated within a short distance of main origin and destination points When integrating collective and individual networks (per scale level) the collective transport system receives priority in the design for instance when it comes to the situation of intermodal transfer points

Ideal then Existingbull First an ideal network is designed ignoring the existing network Subsequently

this ideal structure is confronted with the existing situation The actions that need to be taken to change the existing situation into the ideal situation can then be prioritized This way improvements in the existing networks will be coherent the ideal structure serves as along- term perspective

Quality then Capacity The desired level-of- service or quality of the connections in the network needs to be defined

clearly Quality concerns characteristics such as speed reliability and comfort but also pricing policies and traffic management strategies that are applied to the network An acceptable volume-capacity ratio (capacity) is a prerequisite but capacity should be considered separately from the desired quality

Access Points then the Network A transport network serves to connect access points Therefore it is logical to define first which

access points should be connected and then design the connections between these points (the network) In practice it is often done the other way around A well-known example in Europe is the discussion about which cities should get high-speed train stations on the line from Amsterdam to Paris Whether or not the train was going to stop in The Hague a decision that should have been made before a route was chosen became dependent on the choice for one route or the other

Function then Layout and Technique Before the layout of the various components of the networks (access points links and junctions)

is defined it must be clear what the function of this component is By gearing the layout to the functional requirements it is more likely that this road will be used in accordance with the objectives set it As a consequence changing the function of a road (eg from national to regional) can lead to changing the layout (eg from highway to regional main road) The same principles apply to collective networks For example the choice between bus and rail should depend on the function in some cases both techniques can meet the requirements

NETWORK CHARACTERISTICS Road networks can be defined as series of nodes and links which represents spatial

locations and connections exhibiting geometric variations and topological variations A network can be a set of linear features through which resources flow Nodes (the end points of lines) are used as origins and destinations and links (lines) travers from one node to the other Nodes can have properties but in network analysis we are usually more concerned with the characteristics of the links (Laurini and Thompson 1992) These include

bull lengthbull directionbull connectivity (lines must connect at least two points) andbull pattern There are four main types of classification of network the classification of networks was

discussed by Laurini and Thompson (1992) They suggested the four main types which include

bull oriented with loopsbull unoriented with loopsbull unorientedbull oriented A classification of networks (adapted from Laurini amp Thompson 1992)

Roads can either be oriented or not (ie one way or two way) and usually contain loops For example Rivers flowing in one direction only downhill are best represented by an oriented network Trains usually travel in both directions between stations On smaller lines with only one track the railway network is unoreinted Elsewhere in the network there are lines designated for travel in one direction only for reasons of safety Two-track networks are represented by a pair of oriented links in a network and so either an unoriented or unoriented network with loops may be suitable here

ROAD NETWORK HIERACHY A road hierarchy is a means of defining each roadway in terms of its function such

that appropriate objectives for that roadway can be set and appropriate design criteria can be implemented The road hierarchy can then form the basis of ongoing planning and system management aimed at reducing the mixing of incompatible functions

A road hierarchy differentiates between roads by function Roads at the top of road hierarchy are generally arterial routes that cater for through traffic and often have high traffic volume and operate at high speeds Roads at the lower end of a road hierarchy tend to have a local access function and may have lower volume or speed environments The use of road hierarchy contributes to road safety by reducing turning movements onto and from high volume high speed roads and can also aid the planning of safe and efficient bus cycling and walking routes

The basic road hierarchy comprises freeways arterials collectors and local roads

Freeways These roads provide largely uninterrupted travel often using partial

or full access control and are designed for high speeds Some freeways have collectordistributor lanes (also known as local lanes) which further reduce the number of access ramps that directly interface with the freeway rather the freeway periodically interfaces with these parallel roadways which themselves have multiple on and off-ramps These allow the freeway to operate with less friction at an even higher speed and with higher flow

Arterialsbull Arterials are major roads that are expected to carry large volumes of

traffic Arterials are often divided into major and minor arterials and rural and urban arterials Such roads are usually classified as arterials Frontage roads are often used to reduce the conflict between the high-speed nature of an arterial and property access concerns

FIGURE 1 Important Network Characteristics

Structure then Elementsbull First a perspective on the complete structure of the network

must be developed such as which cities must be connected by the network which scale levels are distinguished etc

bull Only then can a decision be made about the elements (road sections junctions and routes alignment) In practice problems are usually solved at the element level bottleneck by bottleneck

Higher Scale Level then the Lower Scale Levelbull Networks for every scale level are designed independently

following a top-down approach from the higher to the lower scale level with a feedback loop bottom-up

bull Each network is designed to meet its functional requirements optimally In order to achieve coherence between networks of different scale levels access points of higher scale level are automatically included in the lower scale level

Collective Networks then the Individual Networksbull Access to collective transport systems is much more cumbersome than access

to individual transport and therefore the situation of the access points of the collective system (public transport stops) requires more careful consideration than the situation of access points of the individual networks (eg highway and freeway entry points) This is because in the case of collective transport unlike individual transport access and egress by lower-level transport either requires physical transfers from and to other modes or takes place on foot Therefore important public transport nodes are preferably situated within a short distance of main origin and destination points When integrating collective and individual networks (per scale level) the collective transport system receives priority in the design for instance when it comes to the situation of intermodal transfer points

Ideal then Existingbull First an ideal network is designed ignoring the existing network Subsequently

this ideal structure is confronted with the existing situation The actions that need to be taken to change the existing situation into the ideal situation can then be prioritized This way improvements in the existing networks will be coherent the ideal structure serves as along- term perspective

Quality then Capacity The desired level-of- service or quality of the connections in the network needs to be defined

clearly Quality concerns characteristics such as speed reliability and comfort but also pricing policies and traffic management strategies that are applied to the network An acceptable volume-capacity ratio (capacity) is a prerequisite but capacity should be considered separately from the desired quality

Access Points then the Network A transport network serves to connect access points Therefore it is logical to define first which

access points should be connected and then design the connections between these points (the network) In practice it is often done the other way around A well-known example in Europe is the discussion about which cities should get high-speed train stations on the line from Amsterdam to Paris Whether or not the train was going to stop in The Hague a decision that should have been made before a route was chosen became dependent on the choice for one route or the other

Function then Layout and Technique Before the layout of the various components of the networks (access points links and junctions)

is defined it must be clear what the function of this component is By gearing the layout to the functional requirements it is more likely that this road will be used in accordance with the objectives set it As a consequence changing the function of a road (eg from national to regional) can lead to changing the layout (eg from highway to regional main road) The same principles apply to collective networks For example the choice between bus and rail should depend on the function in some cases both techniques can meet the requirements

NETWORK CHARACTERISTICS Road networks can be defined as series of nodes and links which represents spatial

locations and connections exhibiting geometric variations and topological variations A network can be a set of linear features through which resources flow Nodes (the end points of lines) are used as origins and destinations and links (lines) travers from one node to the other Nodes can have properties but in network analysis we are usually more concerned with the characteristics of the links (Laurini and Thompson 1992) These include

bull lengthbull directionbull connectivity (lines must connect at least two points) andbull pattern There are four main types of classification of network the classification of networks was

discussed by Laurini and Thompson (1992) They suggested the four main types which include

bull oriented with loopsbull unoriented with loopsbull unorientedbull oriented A classification of networks (adapted from Laurini amp Thompson 1992)

Roads can either be oriented or not (ie one way or two way) and usually contain loops For example Rivers flowing in one direction only downhill are best represented by an oriented network Trains usually travel in both directions between stations On smaller lines with only one track the railway network is unoreinted Elsewhere in the network there are lines designated for travel in one direction only for reasons of safety Two-track networks are represented by a pair of oriented links in a network and so either an unoriented or unoriented network with loops may be suitable here

ROAD NETWORK HIERACHY A road hierarchy is a means of defining each roadway in terms of its function such

that appropriate objectives for that roadway can be set and appropriate design criteria can be implemented The road hierarchy can then form the basis of ongoing planning and system management aimed at reducing the mixing of incompatible functions

A road hierarchy differentiates between roads by function Roads at the top of road hierarchy are generally arterial routes that cater for through traffic and often have high traffic volume and operate at high speeds Roads at the lower end of a road hierarchy tend to have a local access function and may have lower volume or speed environments The use of road hierarchy contributes to road safety by reducing turning movements onto and from high volume high speed roads and can also aid the planning of safe and efficient bus cycling and walking routes

The basic road hierarchy comprises freeways arterials collectors and local roads

Freeways These roads provide largely uninterrupted travel often using partial

or full access control and are designed for high speeds Some freeways have collectordistributor lanes (also known as local lanes) which further reduce the number of access ramps that directly interface with the freeway rather the freeway periodically interfaces with these parallel roadways which themselves have multiple on and off-ramps These allow the freeway to operate with less friction at an even higher speed and with higher flow

Arterialsbull Arterials are major roads that are expected to carry large volumes of

traffic Arterials are often divided into major and minor arterials and rural and urban arterials Such roads are usually classified as arterials Frontage roads are often used to reduce the conflict between the high-speed nature of an arterial and property access concerns

Structure then Elementsbull First a perspective on the complete structure of the network

must be developed such as which cities must be connected by the network which scale levels are distinguished etc

bull Only then can a decision be made about the elements (road sections junctions and routes alignment) In practice problems are usually solved at the element level bottleneck by bottleneck

Higher Scale Level then the Lower Scale Levelbull Networks for every scale level are designed independently

following a top-down approach from the higher to the lower scale level with a feedback loop bottom-up

bull Each network is designed to meet its functional requirements optimally In order to achieve coherence between networks of different scale levels access points of higher scale level are automatically included in the lower scale level

Collective Networks then the Individual Networksbull Access to collective transport systems is much more cumbersome than access

to individual transport and therefore the situation of the access points of the collective system (public transport stops) requires more careful consideration than the situation of access points of the individual networks (eg highway and freeway entry points) This is because in the case of collective transport unlike individual transport access and egress by lower-level transport either requires physical transfers from and to other modes or takes place on foot Therefore important public transport nodes are preferably situated within a short distance of main origin and destination points When integrating collective and individual networks (per scale level) the collective transport system receives priority in the design for instance when it comes to the situation of intermodal transfer points

Ideal then Existingbull First an ideal network is designed ignoring the existing network Subsequently

this ideal structure is confronted with the existing situation The actions that need to be taken to change the existing situation into the ideal situation can then be prioritized This way improvements in the existing networks will be coherent the ideal structure serves as along- term perspective

Quality then Capacity The desired level-of- service or quality of the connections in the network needs to be defined

clearly Quality concerns characteristics such as speed reliability and comfort but also pricing policies and traffic management strategies that are applied to the network An acceptable volume-capacity ratio (capacity) is a prerequisite but capacity should be considered separately from the desired quality

Access Points then the Network A transport network serves to connect access points Therefore it is logical to define first which

access points should be connected and then design the connections between these points (the network) In practice it is often done the other way around A well-known example in Europe is the discussion about which cities should get high-speed train stations on the line from Amsterdam to Paris Whether or not the train was going to stop in The Hague a decision that should have been made before a route was chosen became dependent on the choice for one route or the other

Function then Layout and Technique Before the layout of the various components of the networks (access points links and junctions)

is defined it must be clear what the function of this component is By gearing the layout to the functional requirements it is more likely that this road will be used in accordance with the objectives set it As a consequence changing the function of a road (eg from national to regional) can lead to changing the layout (eg from highway to regional main road) The same principles apply to collective networks For example the choice between bus and rail should depend on the function in some cases both techniques can meet the requirements

NETWORK CHARACTERISTICS Road networks can be defined as series of nodes and links which represents spatial

locations and connections exhibiting geometric variations and topological variations A network can be a set of linear features through which resources flow Nodes (the end points of lines) are used as origins and destinations and links (lines) travers from one node to the other Nodes can have properties but in network analysis we are usually more concerned with the characteristics of the links (Laurini and Thompson 1992) These include

bull lengthbull directionbull connectivity (lines must connect at least two points) andbull pattern There are four main types of classification of network the classification of networks was

discussed by Laurini and Thompson (1992) They suggested the four main types which include

bull oriented with loopsbull unoriented with loopsbull unorientedbull oriented A classification of networks (adapted from Laurini amp Thompson 1992)

Roads can either be oriented or not (ie one way or two way) and usually contain loops For example Rivers flowing in one direction only downhill are best represented by an oriented network Trains usually travel in both directions between stations On smaller lines with only one track the railway network is unoreinted Elsewhere in the network there are lines designated for travel in one direction only for reasons of safety Two-track networks are represented by a pair of oriented links in a network and so either an unoriented or unoriented network with loops may be suitable here

ROAD NETWORK HIERACHY A road hierarchy is a means of defining each roadway in terms of its function such

that appropriate objectives for that roadway can be set and appropriate design criteria can be implemented The road hierarchy can then form the basis of ongoing planning and system management aimed at reducing the mixing of incompatible functions

A road hierarchy differentiates between roads by function Roads at the top of road hierarchy are generally arterial routes that cater for through traffic and often have high traffic volume and operate at high speeds Roads at the lower end of a road hierarchy tend to have a local access function and may have lower volume or speed environments The use of road hierarchy contributes to road safety by reducing turning movements onto and from high volume high speed roads and can also aid the planning of safe and efficient bus cycling and walking routes

The basic road hierarchy comprises freeways arterials collectors and local roads

Freeways These roads provide largely uninterrupted travel often using partial

or full access control and are designed for high speeds Some freeways have collectordistributor lanes (also known as local lanes) which further reduce the number of access ramps that directly interface with the freeway rather the freeway periodically interfaces with these parallel roadways which themselves have multiple on and off-ramps These allow the freeway to operate with less friction at an even higher speed and with higher flow

Arterialsbull Arterials are major roads that are expected to carry large volumes of

traffic Arterials are often divided into major and minor arterials and rural and urban arterials Such roads are usually classified as arterials Frontage roads are often used to reduce the conflict between the high-speed nature of an arterial and property access concerns

Collective Networks then the Individual Networksbull Access to collective transport systems is much more cumbersome than access

to individual transport and therefore the situation of the access points of the collective system (public transport stops) requires more careful consideration than the situation of access points of the individual networks (eg highway and freeway entry points) This is because in the case of collective transport unlike individual transport access and egress by lower-level transport either requires physical transfers from and to other modes or takes place on foot Therefore important public transport nodes are preferably situated within a short distance of main origin and destination points When integrating collective and individual networks (per scale level) the collective transport system receives priority in the design for instance when it comes to the situation of intermodal transfer points

Ideal then Existingbull First an ideal network is designed ignoring the existing network Subsequently

this ideal structure is confronted with the existing situation The actions that need to be taken to change the existing situation into the ideal situation can then be prioritized This way improvements in the existing networks will be coherent the ideal structure serves as along- term perspective

Quality then Capacity The desired level-of- service or quality of the connections in the network needs to be defined

clearly Quality concerns characteristics such as speed reliability and comfort but also pricing policies and traffic management strategies that are applied to the network An acceptable volume-capacity ratio (capacity) is a prerequisite but capacity should be considered separately from the desired quality

Access Points then the Network A transport network serves to connect access points Therefore it is logical to define first which

access points should be connected and then design the connections between these points (the network) In practice it is often done the other way around A well-known example in Europe is the discussion about which cities should get high-speed train stations on the line from Amsterdam to Paris Whether or not the train was going to stop in The Hague a decision that should have been made before a route was chosen became dependent on the choice for one route or the other

Function then Layout and Technique Before the layout of the various components of the networks (access points links and junctions)

is defined it must be clear what the function of this component is By gearing the layout to the functional requirements it is more likely that this road will be used in accordance with the objectives set it As a consequence changing the function of a road (eg from national to regional) can lead to changing the layout (eg from highway to regional main road) The same principles apply to collective networks For example the choice between bus and rail should depend on the function in some cases both techniques can meet the requirements

NETWORK CHARACTERISTICS Road networks can be defined as series of nodes and links which represents spatial

locations and connections exhibiting geometric variations and topological variations A network can be a set of linear features through which resources flow Nodes (the end points of lines) are used as origins and destinations and links (lines) travers from one node to the other Nodes can have properties but in network analysis we are usually more concerned with the characteristics of the links (Laurini and Thompson 1992) These include

bull lengthbull directionbull connectivity (lines must connect at least two points) andbull pattern There are four main types of classification of network the classification of networks was

discussed by Laurini and Thompson (1992) They suggested the four main types which include

bull oriented with loopsbull unoriented with loopsbull unorientedbull oriented A classification of networks (adapted from Laurini amp Thompson 1992)

Roads can either be oriented or not (ie one way or two way) and usually contain loops For example Rivers flowing in one direction only downhill are best represented by an oriented network Trains usually travel in both directions between stations On smaller lines with only one track the railway network is unoreinted Elsewhere in the network there are lines designated for travel in one direction only for reasons of safety Two-track networks are represented by a pair of oriented links in a network and so either an unoriented or unoriented network with loops may be suitable here

ROAD NETWORK HIERACHY A road hierarchy is a means of defining each roadway in terms of its function such

that appropriate objectives for that roadway can be set and appropriate design criteria can be implemented The road hierarchy can then form the basis of ongoing planning and system management aimed at reducing the mixing of incompatible functions

A road hierarchy differentiates between roads by function Roads at the top of road hierarchy are generally arterial routes that cater for through traffic and often have high traffic volume and operate at high speeds Roads at the lower end of a road hierarchy tend to have a local access function and may have lower volume or speed environments The use of road hierarchy contributes to road safety by reducing turning movements onto and from high volume high speed roads and can also aid the planning of safe and efficient bus cycling and walking routes

The basic road hierarchy comprises freeways arterials collectors and local roads

Freeways These roads provide largely uninterrupted travel often using partial

or full access control and are designed for high speeds Some freeways have collectordistributor lanes (also known as local lanes) which further reduce the number of access ramps that directly interface with the freeway rather the freeway periodically interfaces with these parallel roadways which themselves have multiple on and off-ramps These allow the freeway to operate with less friction at an even higher speed and with higher flow

Arterialsbull Arterials are major roads that are expected to carry large volumes of

traffic Arterials are often divided into major and minor arterials and rural and urban arterials Such roads are usually classified as arterials Frontage roads are often used to reduce the conflict between the high-speed nature of an arterial and property access concerns

Quality then Capacity The desired level-of- service or quality of the connections in the network needs to be defined

clearly Quality concerns characteristics such as speed reliability and comfort but also pricing policies and traffic management strategies that are applied to the network An acceptable volume-capacity ratio (capacity) is a prerequisite but capacity should be considered separately from the desired quality

Access Points then the Network A transport network serves to connect access points Therefore it is logical to define first which

access points should be connected and then design the connections between these points (the network) In practice it is often done the other way around A well-known example in Europe is the discussion about which cities should get high-speed train stations on the line from Amsterdam to Paris Whether or not the train was going to stop in The Hague a decision that should have been made before a route was chosen became dependent on the choice for one route or the other

Function then Layout and Technique Before the layout of the various components of the networks (access points links and junctions)

is defined it must be clear what the function of this component is By gearing the layout to the functional requirements it is more likely that this road will be used in accordance with the objectives set it As a consequence changing the function of a road (eg from national to regional) can lead to changing the layout (eg from highway to regional main road) The same principles apply to collective networks For example the choice between bus and rail should depend on the function in some cases both techniques can meet the requirements

NETWORK CHARACTERISTICS Road networks can be defined as series of nodes and links which represents spatial

locations and connections exhibiting geometric variations and topological variations A network can be a set of linear features through which resources flow Nodes (the end points of lines) are used as origins and destinations and links (lines) travers from one node to the other Nodes can have properties but in network analysis we are usually more concerned with the characteristics of the links (Laurini and Thompson 1992) These include

bull lengthbull directionbull connectivity (lines must connect at least two points) andbull pattern There are four main types of classification of network the classification of networks was

discussed by Laurini and Thompson (1992) They suggested the four main types which include

bull oriented with loopsbull unoriented with loopsbull unorientedbull oriented A classification of networks (adapted from Laurini amp Thompson 1992)

Roads can either be oriented or not (ie one way or two way) and usually contain loops For example Rivers flowing in one direction only downhill are best represented by an oriented network Trains usually travel in both directions between stations On smaller lines with only one track the railway network is unoreinted Elsewhere in the network there are lines designated for travel in one direction only for reasons of safety Two-track networks are represented by a pair of oriented links in a network and so either an unoriented or unoriented network with loops may be suitable here

ROAD NETWORK HIERACHY A road hierarchy is a means of defining each roadway in terms of its function such

that appropriate objectives for that roadway can be set and appropriate design criteria can be implemented The road hierarchy can then form the basis of ongoing planning and system management aimed at reducing the mixing of incompatible functions

A road hierarchy differentiates between roads by function Roads at the top of road hierarchy are generally arterial routes that cater for through traffic and often have high traffic volume and operate at high speeds Roads at the lower end of a road hierarchy tend to have a local access function and may have lower volume or speed environments The use of road hierarchy contributes to road safety by reducing turning movements onto and from high volume high speed roads and can also aid the planning of safe and efficient bus cycling and walking routes

The basic road hierarchy comprises freeways arterials collectors and local roads

Freeways These roads provide largely uninterrupted travel often using partial

or full access control and are designed for high speeds Some freeways have collectordistributor lanes (also known as local lanes) which further reduce the number of access ramps that directly interface with the freeway rather the freeway periodically interfaces with these parallel roadways which themselves have multiple on and off-ramps These allow the freeway to operate with less friction at an even higher speed and with higher flow

Arterialsbull Arterials are major roads that are expected to carry large volumes of

traffic Arterials are often divided into major and minor arterials and rural and urban arterials Such roads are usually classified as arterials Frontage roads are often used to reduce the conflict between the high-speed nature of an arterial and property access concerns

NETWORK CHARACTERISTICS Road networks can be defined as series of nodes and links which represents spatial

locations and connections exhibiting geometric variations and topological variations A network can be a set of linear features through which resources flow Nodes (the end points of lines) are used as origins and destinations and links (lines) travers from one node to the other Nodes can have properties but in network analysis we are usually more concerned with the characteristics of the links (Laurini and Thompson 1992) These include

bull lengthbull directionbull connectivity (lines must connect at least two points) andbull pattern There are four main types of classification of network the classification of networks was

discussed by Laurini and Thompson (1992) They suggested the four main types which include

bull oriented with loopsbull unoriented with loopsbull unorientedbull oriented A classification of networks (adapted from Laurini amp Thompson 1992)

Roads can either be oriented or not (ie one way or two way) and usually contain loops For example Rivers flowing in one direction only downhill are best represented by an oriented network Trains usually travel in both directions between stations On smaller lines with only one track the railway network is unoreinted Elsewhere in the network there are lines designated for travel in one direction only for reasons of safety Two-track networks are represented by a pair of oriented links in a network and so either an unoriented or unoriented network with loops may be suitable here

ROAD NETWORK HIERACHY A road hierarchy is a means of defining each roadway in terms of its function such

that appropriate objectives for that roadway can be set and appropriate design criteria can be implemented The road hierarchy can then form the basis of ongoing planning and system management aimed at reducing the mixing of incompatible functions

A road hierarchy differentiates between roads by function Roads at the top of road hierarchy are generally arterial routes that cater for through traffic and often have high traffic volume and operate at high speeds Roads at the lower end of a road hierarchy tend to have a local access function and may have lower volume or speed environments The use of road hierarchy contributes to road safety by reducing turning movements onto and from high volume high speed roads and can also aid the planning of safe and efficient bus cycling and walking routes

The basic road hierarchy comprises freeways arterials collectors and local roads

Freeways These roads provide largely uninterrupted travel often using partial

or full access control and are designed for high speeds Some freeways have collectordistributor lanes (also known as local lanes) which further reduce the number of access ramps that directly interface with the freeway rather the freeway periodically interfaces with these parallel roadways which themselves have multiple on and off-ramps These allow the freeway to operate with less friction at an even higher speed and with higher flow

Arterialsbull Arterials are major roads that are expected to carry large volumes of

traffic Arterials are often divided into major and minor arterials and rural and urban arterials Such roads are usually classified as arterials Frontage roads are often used to reduce the conflict between the high-speed nature of an arterial and property access concerns

Roads can either be oriented or not (ie one way or two way) and usually contain loops For example Rivers flowing in one direction only downhill are best represented by an oriented network Trains usually travel in both directions between stations On smaller lines with only one track the railway network is unoreinted Elsewhere in the network there are lines designated for travel in one direction only for reasons of safety Two-track networks are represented by a pair of oriented links in a network and so either an unoriented or unoriented network with loops may be suitable here

ROAD NETWORK HIERACHY A road hierarchy is a means of defining each roadway in terms of its function such

that appropriate objectives for that roadway can be set and appropriate design criteria can be implemented The road hierarchy can then form the basis of ongoing planning and system management aimed at reducing the mixing of incompatible functions

A road hierarchy differentiates between roads by function Roads at the top of road hierarchy are generally arterial routes that cater for through traffic and often have high traffic volume and operate at high speeds Roads at the lower end of a road hierarchy tend to have a local access function and may have lower volume or speed environments The use of road hierarchy contributes to road safety by reducing turning movements onto and from high volume high speed roads and can also aid the planning of safe and efficient bus cycling and walking routes

The basic road hierarchy comprises freeways arterials collectors and local roads

Freeways These roads provide largely uninterrupted travel often using partial

or full access control and are designed for high speeds Some freeways have collectordistributor lanes (also known as local lanes) which further reduce the number of access ramps that directly interface with the freeway rather the freeway periodically interfaces with these parallel roadways which themselves have multiple on and off-ramps These allow the freeway to operate with less friction at an even higher speed and with higher flow

Arterialsbull Arterials are major roads that are expected to carry large volumes of

traffic Arterials are often divided into major and minor arterials and rural and urban arterials Such roads are usually classified as arterials Frontage roads are often used to reduce the conflict between the high-speed nature of an arterial and property access concerns

The basic road hierarchy comprises freeways arterials collectors and local roads

Freeways These roads provide largely uninterrupted travel often using partial

or full access control and are designed for high speeds Some freeways have collectordistributor lanes (also known as local lanes) which further reduce the number of access ramps that directly interface with the freeway rather the freeway periodically interfaces with these parallel roadways which themselves have multiple on and off-ramps These allow the freeway to operate with less friction at an even higher speed and with higher flow

Arterialsbull Arterials are major roads that are expected to carry large volumes of

traffic Arterials are often divided into major and minor arterials and rural and urban arterials Such roads are usually classified as arterials Frontage roads are often used to reduce the conflict between the high-speed nature of an arterial and property access concerns

Collectorsbull Collectors reduce weaving on freeways collect traffic from local roads and

distribute it to arterials Traffic using a collector is usually going to or coming from somewhere nearby

Local roads At the bottom of the hierarchy are local streets and roads These roads have

the lowest speed limit and carry low volumes of traffic In some areas these roads may be unpaved A well formed road hierarchy will reduce overall impact of traffic by-

bull concentrating longer distance flow onto routes in less sensitive locationsbull ensuring land uses and activities that are incompatible with traffic flow are

restricted from routes where traffic movement should predominatebull preserving areas where through traffic is discouraged The road hierarchy principles will assist planning agencies with-bull orderly planning of heavy vehicle and dangerous goods routesbull planning and provision of public transport routesbull planning and provision of pedestrian and bicycle routes

A road network concept

A road network in Ikoyi-dolphin-marina ndash sangross interchange

ASSESSMENT AND ANALYSIS Network analysis enables us to solve problems such as finding the most

efficient travel route generating travel directions finding the closest facility defining service areas based on travel time Networks are all around us Roads railways cables pipelines streams and even glaciers are phenomena that frequently need to be represented and analysed as a network Networks are used to move people transport goods communicate information and control the flow of matter and energy It is not surprising then that techniques have been developed to analyse these most geographical phenomena

Algorithms for network operations At the heart of a network analysis is the search procedure One can for

example selectbull links that take you as far away from the start node as possible never turning

back Alternatively one can search all the links that propagate from a node moving out one link at a time and gradually accumulating a cost of travel in all directions from a start node Or one can seek to find a route that passes through the fewest number of nodes even if it is not necessarily the route of lowest cost

Applications of network analysisbull Routing Finding shortest routes is probably the commonest routing problem to

GIS users Finding the shortest route from A to B through a road network is crucial for emergency services business journeys or simply planning routes for holiday makers touring a region In order to carry out such operations it is important to construct an appropriate network Details of connectivity one way streets possible turns and speed limits will be required

bull Resource allocation Another application of network analysis is resource allocation The objective is to create service areas around a service centre and if implemented successfully allows an organization to optimize the distribution of the resources based on the capacity of each facility For example centres may be schools with a maximum capacity for children health centres with a capacity for patients or warehouses with a capacity for goods Allocation algorithms use these centres as destinations then model how people or goods will travel through the network to get there The result is a map that shows the areas served by each service facility eg a school or health centre catchment area or the warehousersquos distribution area The algorithms usually work by allocating links in the network to the nearest centre taking into account of course the attributes such as one way streets barriers to movement and so on

CONTROL AND OPERATIONS Traffic Control Measures Traffic control aims to manage and control the movement of traffic on roads to

optimize the use of existing road capacity Traffic control covers all measures aimed at distributing and controlling road traffic flows in time and space in order to avoid the onset of incidents or to reduce their impacts Traffic control is carried out by network operators and controllers with reference to predetermined traffic management policies and plans In most countries it is an activity done in coordination with the authorities in charge of traffic policing often under their direct control Traffic control also includes the use of CCTV and other means of monitoring traffic by local or State roadways authorities to manage traffic flows and providing advice concerning traffic congestion

bull It is possible to distinguish betweenbull direct control measures ndash using traffic lights ldquosmartrdquo barriers and Variable Message

Signs (VMS) to allocate traffic priorities in time and spacebull enforcement measures against violations of control measures and traffic laws ndash for

example speed enforcement cameras and red-light running detection linked to ANPR cameras

bull indirect control measures ndash mainly information and recommendations to drivers that will affect the behaviour of individual vehicles for example radio broadcasts pre-trip information (via internet and mobile devices) in-vehicle routing and on-board navigation systems

A road network in Ikoyi-dolphin-marina ndash sangross interchange

ASSESSMENT AND ANALYSIS Network analysis enables us to solve problems such as finding the most

efficient travel route generating travel directions finding the closest facility defining service areas based on travel time Networks are all around us Roads railways cables pipelines streams and even glaciers are phenomena that frequently need to be represented and analysed as a network Networks are used to move people transport goods communicate information and control the flow of matter and energy It is not surprising then that techniques have been developed to analyse these most geographical phenomena

Algorithms for network operations At the heart of a network analysis is the search procedure One can for

example selectbull links that take you as far away from the start node as possible never turning

back Alternatively one can search all the links that propagate from a node moving out one link at a time and gradually accumulating a cost of travel in all directions from a start node Or one can seek to find a route that passes through the fewest number of nodes even if it is not necessarily the route of lowest cost

Applications of network analysisbull Routing Finding shortest routes is probably the commonest routing problem to

GIS users Finding the shortest route from A to B through a road network is crucial for emergency services business journeys or simply planning routes for holiday makers touring a region In order to carry out such operations it is important to construct an appropriate network Details of connectivity one way streets possible turns and speed limits will be required

bull Resource allocation Another application of network analysis is resource allocation The objective is to create service areas around a service centre and if implemented successfully allows an organization to optimize the distribution of the resources based on the capacity of each facility For example centres may be schools with a maximum capacity for children health centres with a capacity for patients or warehouses with a capacity for goods Allocation algorithms use these centres as destinations then model how people or goods will travel through the network to get there The result is a map that shows the areas served by each service facility eg a school or health centre catchment area or the warehousersquos distribution area The algorithms usually work by allocating links in the network to the nearest centre taking into account of course the attributes such as one way streets barriers to movement and so on

CONTROL AND OPERATIONS Traffic Control Measures Traffic control aims to manage and control the movement of traffic on roads to

optimize the use of existing road capacity Traffic control covers all measures aimed at distributing and controlling road traffic flows in time and space in order to avoid the onset of incidents or to reduce their impacts Traffic control is carried out by network operators and controllers with reference to predetermined traffic management policies and plans In most countries it is an activity done in coordination with the authorities in charge of traffic policing often under their direct control Traffic control also includes the use of CCTV and other means of monitoring traffic by local or State roadways authorities to manage traffic flows and providing advice concerning traffic congestion

bull It is possible to distinguish betweenbull direct control measures ndash using traffic lights ldquosmartrdquo barriers and Variable Message

Signs (VMS) to allocate traffic priorities in time and spacebull enforcement measures against violations of control measures and traffic laws ndash for

example speed enforcement cameras and red-light running detection linked to ANPR cameras

bull indirect control measures ndash mainly information and recommendations to drivers that will affect the behaviour of individual vehicles for example radio broadcasts pre-trip information (via internet and mobile devices) in-vehicle routing and on-board navigation systems

ASSESSMENT AND ANALYSIS Network analysis enables us to solve problems such as finding the most

efficient travel route generating travel directions finding the closest facility defining service areas based on travel time Networks are all around us Roads railways cables pipelines streams and even glaciers are phenomena that frequently need to be represented and analysed as a network Networks are used to move people transport goods communicate information and control the flow of matter and energy It is not surprising then that techniques have been developed to analyse these most geographical phenomena

Algorithms for network operations At the heart of a network analysis is the search procedure One can for

example selectbull links that take you as far away from the start node as possible never turning

back Alternatively one can search all the links that propagate from a node moving out one link at a time and gradually accumulating a cost of travel in all directions from a start node Or one can seek to find a route that passes through the fewest number of nodes even if it is not necessarily the route of lowest cost

Applications of network analysisbull Routing Finding shortest routes is probably the commonest routing problem to

GIS users Finding the shortest route from A to B through a road network is crucial for emergency services business journeys or simply planning routes for holiday makers touring a region In order to carry out such operations it is important to construct an appropriate network Details of connectivity one way streets possible turns and speed limits will be required

bull Resource allocation Another application of network analysis is resource allocation The objective is to create service areas around a service centre and if implemented successfully allows an organization to optimize the distribution of the resources based on the capacity of each facility For example centres may be schools with a maximum capacity for children health centres with a capacity for patients or warehouses with a capacity for goods Allocation algorithms use these centres as destinations then model how people or goods will travel through the network to get there The result is a map that shows the areas served by each service facility eg a school or health centre catchment area or the warehousersquos distribution area The algorithms usually work by allocating links in the network to the nearest centre taking into account of course the attributes such as one way streets barriers to movement and so on

CONTROL AND OPERATIONS Traffic Control Measures Traffic control aims to manage and control the movement of traffic on roads to

optimize the use of existing road capacity Traffic control covers all measures aimed at distributing and controlling road traffic flows in time and space in order to avoid the onset of incidents or to reduce their impacts Traffic control is carried out by network operators and controllers with reference to predetermined traffic management policies and plans In most countries it is an activity done in coordination with the authorities in charge of traffic policing often under their direct control Traffic control also includes the use of CCTV and other means of monitoring traffic by local or State roadways authorities to manage traffic flows and providing advice concerning traffic congestion

bull It is possible to distinguish betweenbull direct control measures ndash using traffic lights ldquosmartrdquo barriers and Variable Message

Signs (VMS) to allocate traffic priorities in time and spacebull enforcement measures against violations of control measures and traffic laws ndash for

example speed enforcement cameras and red-light running detection linked to ANPR cameras

bull indirect control measures ndash mainly information and recommendations to drivers that will affect the behaviour of individual vehicles for example radio broadcasts pre-trip information (via internet and mobile devices) in-vehicle routing and on-board navigation systems

Applications of network analysisbull Routing Finding shortest routes is probably the commonest routing problem to

GIS users Finding the shortest route from A to B through a road network is crucial for emergency services business journeys or simply planning routes for holiday makers touring a region In order to carry out such operations it is important to construct an appropriate network Details of connectivity one way streets possible turns and speed limits will be required

bull Resource allocation Another application of network analysis is resource allocation The objective is to create service areas around a service centre and if implemented successfully allows an organization to optimize the distribution of the resources based on the capacity of each facility For example centres may be schools with a maximum capacity for children health centres with a capacity for patients or warehouses with a capacity for goods Allocation algorithms use these centres as destinations then model how people or goods will travel through the network to get there The result is a map that shows the areas served by each service facility eg a school or health centre catchment area or the warehousersquos distribution area The algorithms usually work by allocating links in the network to the nearest centre taking into account of course the attributes such as one way streets barriers to movement and so on

CONTROL AND OPERATIONS Traffic Control Measures Traffic control aims to manage and control the movement of traffic on roads to

optimize the use of existing road capacity Traffic control covers all measures aimed at distributing and controlling road traffic flows in time and space in order to avoid the onset of incidents or to reduce their impacts Traffic control is carried out by network operators and controllers with reference to predetermined traffic management policies and plans In most countries it is an activity done in coordination with the authorities in charge of traffic policing often under their direct control Traffic control also includes the use of CCTV and other means of monitoring traffic by local or State roadways authorities to manage traffic flows and providing advice concerning traffic congestion

bull It is possible to distinguish betweenbull direct control measures ndash using traffic lights ldquosmartrdquo barriers and Variable Message

Signs (VMS) to allocate traffic priorities in time and spacebull enforcement measures against violations of control measures and traffic laws ndash for

example speed enforcement cameras and red-light running detection linked to ANPR cameras

bull indirect control measures ndash mainly information and recommendations to drivers that will affect the behaviour of individual vehicles for example radio broadcasts pre-trip information (via internet and mobile devices) in-vehicle routing and on-board navigation systems

CONTROL AND OPERATIONS Traffic Control Measures Traffic control aims to manage and control the movement of traffic on roads to

optimize the use of existing road capacity Traffic control covers all measures aimed at distributing and controlling road traffic flows in time and space in order to avoid the onset of incidents or to reduce their impacts Traffic control is carried out by network operators and controllers with reference to predetermined traffic management policies and plans In most countries it is an activity done in coordination with the authorities in charge of traffic policing often under their direct control Traffic control also includes the use of CCTV and other means of monitoring traffic by local or State roadways authorities to manage traffic flows and providing advice concerning traffic congestion

bull It is possible to distinguish betweenbull direct control measures ndash using traffic lights ldquosmartrdquo barriers and Variable Message

Signs (VMS) to allocate traffic priorities in time and spacebull enforcement measures against violations of control measures and traffic laws ndash for

example speed enforcement cameras and red-light running detection linked to ANPR cameras

bull indirect control measures ndash mainly information and recommendations to drivers that will affect the behaviour of individual vehicles for example radio broadcasts pre-trip information (via internet and mobile devices) in-vehicle routing and on-board navigation systems

CONCLUSION The socio-economic development and subsequent economic growth of

any nation is strongly linked to its transport infrastructure The level and quality of transportation systems in any area are of crucial significance in influencing political economic and social progress and these must be considered at every stage of local national and regional development planning Without good roads it is difficult to have socially inclusive development interventions Improved road networks bring many benefits these include improved accessibility to social infrastructure (schools churches and health centres) increased access to education and health facilities and improved social interaction and mobility Direct benefits of improved road networks include reduced vehicle operating costs savings in travel time reduced accident costs resulting from the upgrade of the proposed roads possible savings in road maintenance costs (because roads are bound to withstand harsh weather if they are well-maintained) A high quality road network is essential not only for connecting key urban centres but for improving connectivity of more isolated local communities to whom public transport options are limited

REFERENCESbull Coops NC and Waring RH (2001)the use of multi scale remote sensing

imagery to derive regional estimates of forest growth capacity using 3-PGSbull Rodrigue et al (2006) The Geography of transport system New york

Routledgebull Verma RK et al (2008)Application of remote sensing and GIS technique for

efficient urban planning GISdevelopmentNetapplicationurbanbull RaoKM and Jayasreo K (2010)Rural infrastructural planning with emphasis

on road network connectivity by coplanar concurrent theory httpwwwgisdevelopmentnetapplicationutilitytransportmi03151htm

bull Abosede A J (2000) Sampling and Sampling Techniques in Research Methods in the Social and Management Science Centre for Sandwich Programmes (CESAP) Ogun State University Ago-Iwoye 175-192

bull Aderamo A J (2003) A Graph Theoretic Analysis of Intra-Urban Road Network in Ilorin Nigeria Research for Development 17 1 amp 2 18 1 amp 2 (December 2003) 221 ndash 240

REFERENCESbull Coops NC and Waring RH (2001)the use of multi scale remote sensing

imagery to derive regional estimates of forest growth capacity using 3-PGSbull Rodrigue et al (2006) The Geography of transport system New york

Routledgebull Verma RK et al (2008)Application of remote sensing and GIS technique for

efficient urban planning GISdevelopmentNetapplicationurbanbull RaoKM and Jayasreo K (2010)Rural infrastructural planning with emphasis

on road network connectivity by coplanar concurrent theory httpwwwgisdevelopmentnetapplicationutilitytransportmi03151htm

bull Abosede A J (2000) Sampling and Sampling Techniques in Research Methods in the Social and Management Science Centre for Sandwich Programmes (CESAP) Ogun State University Ago-Iwoye 175-192

bull Aderamo A J (2003) A Graph Theoretic Analysis of Intra-Urban Road Network in Ilorin Nigeria Research for Development 17 1 amp 2 18 1 amp 2 (December 2003) 221 ndash 240

THANKYOU FOR

LISTENING

• DEPARTMENT OF CIVIL ENGINEERING BAYERO UNIVERSITY KANO NIGERI
• Slide 2
• Slide 3
• Slide 4
• NETWORK DESIGN METHOD
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• NETWORK CHARACTERISTICS
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• A road network concept
• A road network in Ikoyi-dolphin-marina ndash sangross interchange
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Slide 22