traffic signals using irc

8/18/2019 Traffic Signals Using Irc

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Abstract

As we all know traffic volume is increasing day by day in cities due to growth of

industrialization and urbanization of cities. Thus to manage the present traffic volume new

methods were adopted to provide better, easy and safe movement of traffic. The traffic

conflictions are major on intersections of two roads. Traffic signals is a way

to control the traffic at the intersections of the cities and avoid the conflictions of the vehicles at

the intersection. Traffic signals also helps the traffic to move with safety and

easily, which tends to minimize the collision between the vehicles at the intersection. In this

dissertation we surveyed the traffic volume of intersections of the Vidisha city and

traffic signals were designed at each intersection . The one part of the thesis is survey of traffic

volume, which is done by manual method, wherein the vehicles are countedmanually without using any device or sensor with respective vehicle categories like passenger,

commercial and agricultural etc. and the other part is design of traffic signals, which is done

according to the I! method of signal design by adopting ma"imum #!$ on the

intersection in each direction. The design of traffic signals at these intersections in vidisha will

help the growing traffic to move with ease and safety and also helps in reducing the

accident rate at the intersections due to congestions and confliction between vehicles.

Key words: Vidisha, !ontrolling Traffic


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TABLE OF CONTENTS

%erial no. Title #age no.

&efinitions

!hapter ' Introduction

'.' #urpose of Traffic %ignals

'.( Intersection &esign and its elationship to %ignal Timing

'.) *bjectives of +asic %ignal Timing #arameters and %ettings

'.).' *ther #olicy !onsiderations

!hapter ( iterature eview

!hapter ) %tudy Area

!hapter - *perational and %afety Analysis

-.' !haracteristics Affecting %ignal Timing

-.'.' ocation

-.'.( Transportation etwork !haracteristics

-.'.) Intersection /eometry

-.'.- $ser !haracteristics

-.( +asic *perational #rinciples

!hapter 0 &esign of Traffic %ignals

0.' Traffic %tudy

0.( %ignal &esigning

!onclusion

eferences


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Definitions

Accessible #edestrian %ignal1

A device that communicates information about pedestrian timing in nonvisual format

such as audible tones, verbal messages, and2or vibrating surfaces.

!ycle ength1

The time re3uired for a complete se3uence of signal indications.

!onventional #edestrian %ignal1

A device that communicates information about pedestrian timing in conventional 4i.e.,

visual5 format.

!oordinated Traffic %ignal %ystem1

A system of traffic signals for which a timed relationship e"ists between adjacent traffic

signals within the system.

6ffective green time1

The time during which a given traffic movement or set of movements may proceed7 it is

e3ual to the cycle length minus the effective red time.

6ffective red time1

The time during which a given traffic movement or set of movements is directed to stop7

it is e3ual to the cycle length minus the effective green time.

6mergency Vehicle #re8emption1

Transfer of normal operation of a traffic signal to a special mode of operation that 3uickly

gives the green phase for the direction of traffic from which the approaching emergency

vehicle is arriving.


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ost Time1

The portion of time at the beginning of each green period and a portion of each yellow

change plus red clearance period that is not usable by vehicles.

9ajor %treet1

The street normally carrying the higher volume of vehicular traffic at an intersection.

9inor %treet1

The street normally carrying the lower volume of vehicular traffic at an intersection.

#eak8hour factor1

The hourly volume during the ma"imum8volume hour of the day divided by four times

the peak '08min flow rate within the peak hour7 a measure of traffic demand fluctuation within

the peak hour.

#edestrian Indication1

A signal head, which contains the symbols :A;I/ #6%* 4symbolizing :A;5

and $#AI%6& low ate1

The e3uivalent hourly rate at which vehicles can traverse an intersection approach under

prevailing conditions, assuming a constant green indication at all time and no loss time, in

vehicles per hour or vehicles per hour per lane.


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Total lost time1

The time per signal cycle during which the intersection is effectively not used by any

movement7 this occurs during the change and clearance intervals and at the beginning of

most phases.

Traffic %ignal1

A device to warn, control, or direct at least one traffic movement at an intersection.

?ellow #edestrian Activated >lasher1

?ellow flashing signal that is activated by the pedestrian and which emphasize the

location of a crosswalk.


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CHAPTER

!NTROD"CT!ON

The traffic of our country is growing day by day , by which the control and management

of traffic is a major problem. The traffic volume is increasing regularly so controlling heavy

traffic is very hard for the traffic police and the accident rate are also increasing at intersections.

%o to overcome the crises of increasing traffic, design of traffic signals on s3uares of the cities

are necessary. The traffic signal helps the vehicle to move on s3uare or intersections

with safety and 6ase. Thus the design of traffic signal is an essential part of traffic control in

major cities, which tend to economical and safe method for proper operation of vehiclesat intersections. Traffic signals are the traffic control measure which is used to control the

conflicts between vehicles on s3uares, where traffic flow intensity is high, mostly in cities.

The first traffic signal was fi"ed in ondon in '@@ , which was a semaphore8 arm type signal.

The sections where large number of crossings and right turn traffics are available

there are a possibility of several accidents because of non orderly movement of vehicles. In

earlier time traffic is controlled by traffic police manually by showing signs to the

traffic in each direction but as the traffic volume is growing large and large it is not possible to

handle the traffic by one traffic police so as to under come this problem traffic signals

has been designed to control the traffic with accuracy and timely. The traffic signals has three

lights orderly red, yellow, green, by which the can guide the traffic whether to move or stop.

The main purpose or function of traffic signal is to draw attention, provide meaning and time to

respond and to have minimum waste of time. The main object of traffic signals is to avoid

confliction of vehicles, easy and safe movement of vehicles at intersections. Traffic signal guides

the vehicles to move or not by which the confliction between vehicles are

avoided, the signal helps the vehicle to move or stop at intersection according to the direction of

movement of vehicle.


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# P$r%ose of Traffic Si&na's:

The 9anual on $niform Traffic !ontrol &evices 49$T!&5 defines a traffic control

signal as any highway traffic signal by which traffic is alternatively directed to stop and

permitted to proceed. Traffic is defined as pedestrians, bicyclists, ridden or herded animals,

vehicles, streetcars, and other conveyances either singularly or together while using any highway

for purposes of travel.

It is with this need to assign the right of way at locations that we consider the dual

purpose of traffic signals efficiency and safety which in some cases seem to be conflicting.

%afety may be seen as an element needed to be sacrificed in order to achieve improvements in

efficiency and meet ever8increasing demands. The reality is that traffic signals can, and in fact

must, serve both operational efficiency and safety based on the conditions. The 9$T!& goes on

to describe that traffic control signals can be ill8designed, ineffectively placed, improperly

operated, or poorly maintained, with resulting outcomes of e"cessive delay, disobedience of the

indication, avoidance, and increases in the fre3uency of collisions.

A traffic signal that is properly designed and timed can be e"pected to provide one or more of

the following benefits1

'. #rovide for the orderly and efficient movement of people.

(. 6ffectively ma"imize the volume movements served at the intersection.

). educe the fre3uency and severity of certain types of crashes.

-. #rovide appropriate levels of accessibility for pedestrians and side street traffic.

The degree to which these benefits are realized is based partly on the design and partly on the

need for a signal. A poorly designed signal timing plan or an unneeded signal may make the

intersection less efficient, less safe, or both.

#( !ntersection Desi&n and its Re'ations)i% to Si&na' Ti*in&

The design of the intersection has a direct influence on its safety and operation from a

design and user8ability perspective. &esign elements that are particularly relevant include the


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number of lanes provided on each approach and for each movement, whether there are shared

thru8and8turn lanes, the length of turn bays, the turning radii 4especially important for

pedestrians5, the presence of additional through lanes in the vicinity of the intersection, the size

and location of detectors, and presence or absence of left8turn phasing. *ther geometric features,

like additional through or turn lanes, can also have a significant positive impact on intersection

capacity, provided that they are sufficiently long. The other aspect of intersection design is the

perception and reaction of the end users. Various decisions need to be made as a user approaches

the intersection, which makes it important to simplify the decision making process.

#+ Ob,ecti-es of Basic Si&na' Ti*in& Para*eters and Settin&s

A primary objective of signal timing settings is to move people through an intersection

safely and efficiently. Achieving this objective re3uires a plan that allocates right8of8way to the

various users. This plan should accommodate fluctuations in demand over the course of each

day, week,and year.

#+#Ot)er Po'icy Considerations

Additional policy issues that are more detail oriented include1

B The ma"imum allowable cycle length7

B :hether the agency will allow lagging and leading left turns by intersection or variable by time

of day7

B :hether the agency will allow the skipping of left turn phases under low volume conditions7

B :hether ma"imum green times will operate within the coordination plan7

B :hether transit preferential policies such as transit signal priority will be implemented

aggressively7

B The number of signal timing plans 4time of day plans5 in operation per day to respond to

fluctuating traffic demand7

B :ill coordination timing plans allow intersections to temporarily leave coordination to

accomplish tasks 4i.e. serve pedestrian calls57 and


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B :hether coordination patterns will be selected by time8of8day or by real8time traffic data.


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CHAPTER (

L!TERAT"RE RE.!E/

TA>>I! %I/A &6%I/ 9A$A

!ity of Tucson &epartment of Transportation Traffic 6ngineering &ivision

This first edition of the !ity of Tucson Traffic %ignal &esign 9anual e"pands upon e"isting

guidelines to more completely identify guidelines, practices, and standards for the design of !ity

of Tucson traffic signals. oadway lighting re3uirements are addressed only to the e"tent that

intersection lighting is provided at signalized intersections. The purpose of this manual is to

provide a consistent set of guidelines, practices, and standards for use by designers, contractors,and !ity of Tucson &epartment of Transportation Traffic 6ngineering &ivision

4!*T2&*T2T6&5 staff.

This manual supplements the (CCC edition and subse3uent updates of the 9anual on $niform

Traffic !ontrol &evices 49$T!&5. It should be used in conjunction with the 'DD- edition of the

#ima !ounty2!ity of Tucson %tandard %pecifications for #ublic Improvements, and the #ima

!ounty2!ity of Tucson %tandard &etails for #ublic Improvements.

TA>>I! V*$96 !*$T%

Traffic volume studies are conducted to determine the number, movements, and classifications of

roadway vehicles at a given location. These data can help identify critical flow time periods,

determine the influence of large vehicles or pedestrians on vehicular traffic flow, or document

traffic volume trends. The length of the sampling period depends on the type of count being

taken and the intended use of the data recorded.


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CHAPTER +

ST"D0 AREA


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ATIT$&6 A& */IT$&61

%uchitra +us %top atitude is1 'E.-DD0(E

%uchitra +us %top ongitude is1 [email protected])D@DDDDDD@

CHAPER 1


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OPERAT!ONAL AND SAFET0 ANAL0S!S

The purpose of this chapter is to summarize some of the common techni3ues used to

assess the operational and safety performance of signal timing. The chapter begins by presenting

an overview of the characteristics that affect signal timing, including both system and user characteristics. It then presents discussions of operational and safety performance measures and

techni3ues to evaluate those performance measures. >inally, the chapter presents a discussion of

signal warrants as presented in the 9anual on $niform Traffic !ontrol &evices and how those

warrants relate to signal timing

1#CHARACTER!ST!CS AFFECT!N2 S!2NAL T!3!N2

%everal overall features affect implementation of signal timing including1

B ocation

B Transportation network characteristics

B Intersection geometry

B $ser characteristics

The following sections further describe many characteristics and dynamic nature influencing

signal timing.

1## Location

*ne of the primary factors affecting overall signal timing is the environment in which the

intersection or intersections being timed are located. $rban environments are fre3uently

characterized by lower speeds and higher degrees of congestion. In addition, urban environments

are fre3uently characterized by higher pedestrian, cyclist, and transit use that often re3uire

priority in consideration. ural environments, on the other hand, are typically higher speed but

with lower levels of traffic volumes and fewer, if any, pedestrians, cyclists, and transit vehicles.

As a result, signal timing for rural environments is typically dominated by efforts to safely

manage high speed approaches7 capacity is seldom a constraint. %uburban environments often

present a challenging mi" of these characteristics. %uburban environments are oftencharacterized by high speeds during the off8peak periods and capacity8constrained conditions

during the peak periods. This re3uires a careful consideration and balance of both safety aspects

and operational efficiency.

1##( Trans%ortation Networ4 C)aracteristics


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The configuration of the transportation network under consideration can have a

significant impact on the way its traffic signals are timed. Isolated intersections can be timed

without the e"plicit consideration of other traffic signals, allowing the fle"ibility to either set or

target cycle lengths that are optimal for the individual intersection. In these cases, good detection

design often yields measurable operational and safety benefits.

1##+ !ntersection 2eo*etry

The overall geometry of an intersection determines its ability to efficiently and safely

serve user demand. #edestrians are often crossing lanes of traffic, whereas transit, bicycles, and

vehicular traffic are using the travel lanes provided at the intersection. The number of lanes

provided for each approach has a significant impact on the capacity of the intersection and,

therefore, the ability for signal timing to efficiently serve demand.

>or e"ample, a movement served by two lanes rather than one has a higher capacity and thus

re3uires less green time to serve demand.


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Traffic demand represents the arrival pattern of vehicles at an intersection 4or the system,

if one considers a group of intersections together5, while traffic volume is the measured departure

rate from the intersection. If more vehicles arrive for a movement than can be served, the

movement is considered to be operating over capacity 4oversaturated5. igure )8( below. The signal display is presented on the horizontal a"is, the instantaneous

flow of vehicles on the vertical a"is. &uring the time while the movement is receiving a red

indication, vehicles arrive and form a 3ueue, and there is no flow. $pon receiving a green

indication, it takes a few seconds for the driver of the first vehicle to recognize that the signal has

turned green and to get the vehicle in motion. The ne"t few vehicles also take some time toaccelerate. This is defined as the start8up lost time or start8up delay and is commonly assumed to

be appro"imately ( seconds. After appro"imately the fourth vehicle in the 3ueue, the flow rate

tends to stabilize at the ma"imum flow rate that the conditions will allow, known as the

saturation flow rate. This is generally sustained until the last vehicle in the 3ueue departs the

intersection. $pon termination of the green indication, some vehicles continue to pass through

the intersection during the yellow change interval7 this is known as yellow e"tension. The usable

amount of green time, that is, the duration of time between the end of the start8up delay and the

end of the yellow e"tension, is referred to as the effective green time for the

movement. The unused portion of the yellow change interval and red clearance interval is called

clearance lost time.


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CHAPTER 5

DES!2N OF TRAFF!C S!2NALS

The designing of traffic signals has two phases. The phases are listed below1

• TA>>I! %T$&?

• %I/A% &6%I/I/

Traffic signals can be designed using two methods. They are

I! method

:ebster method


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5# Traffic st$dy

"sin& co$nt %eriod to deter*ine st$dy *et)od

Two methods are available for conducting traffic volume counts1

4'5 manual and

4(5 automatic

3an$a' co$nts are typically used to gather data for determination of vehicle classification,

turning movements, direction of travel, pedestrian movements, or vehicle occupancy.

A$to*atic co$nts are typically used to gather data for determination of vehicle hourly patterns,

daily or seasonal variations and growth trends, or annual traffic estimates.

The selection of study method should be determined using the count period. The count period

should be representative of the time of day, day of month, and month of year for the study area.

The study methods for short duration counts are described in this chapter in order from least

e"pensive 4manual5 to most e"pensive 4automatic5, assuming the user is starting with no

e3uipment.

3an$a' co$nt *et)od:

9ost applications of manual counts re3uire small samples of data at any given location.

9anual counts are sometimes used when the effort and e"pense of automated e3uipment are not

justified. 9anual counts are necessary when automatic e3uipment is not available. 9anual

counts are typically used for periods of less than a day. ormal intervals for a manual count are

0,'C, or '0 minutes. Traffic counts during a 9onday morning rush hour and a >riday evening

rush hour may show e"ceptionally high volumes and are not normally used in analysis7 therefore,

counts are usually conducted on a Tuesday, :ednesday, or Thursday.

9anual !ount ecording 9ethods1

9anual counts are recorded using one of three methods1 tally sheets, mechanical

counting boards, or electronic counting boards.


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5#( S!2NAL DES!2N!N2:

!RC *et)od

• The pedestrian green time re3uired for the major and minor roads are calculated based on

walking speed of '.( m2sec. and initial walking time of E.C secs.

• These are the minimum green time re3uired for the vehicular traffic on the minor and

major roads respectively.

• The green time re3uired for the vehicular traffic on the major road is increased in the

proportion to the traffic on the two approach roads.

• The cycle time is calculated after allowing amber time of (.C secs each

• The minimum green time re3uired for clearing vehicles arriving during a cycle is a

determined for each lane of the approach road assuming that the first vehicle will

take .C secs. And th subse3uent vehicles 4#!$5 of the 3ueue will be cleared at a rate of

(.C secs. The minimum green time re3uired for the vehicular traffic

on any of the approaches is limited to ' secs.

• The optimum signal cycle time is calculated using :ebsterHs formula The saturation flow

values may be assumed as '@0C,'@DC,'D0C,((0C,(00Cand (DDC #!$ per hour for the

approach roadway widths 4keb to median or centerline5 of ).C,).0,-.C,-.0,0.C and 0.0m7

for width above 0.0m, the saturation flow may be assumed as 0(0 #!$ per hour per

meter width. The lost time is calculated from the amber time, inter8green time

and the initial delay of -.C secs. >or the first vehicle, on each leg.

• The signal cycle time and the phases may be revised keeping in view the green time

re3uired for clearing the vehicles and the optimum cycle length determined in steps 4iv5

and4v5 above.


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S!2NAL DES!2N OF !NTERSECT!ON:

&esign traffic on road ' '-E'2(E) #!$2hour

&esign traffic on road ( )D( #!$2hour

:idth of road ' 'Cm

:idth of road ( D.0m

'5 #edestrian green signal time for road '

10

1.2+7

'0.)) sec.

#edestrian green signal time for road (

9.5

1.2+7

'-.D' sec.

(5 /reen signal time for vehicles on road (,/( '0.)) sec

/reen signal time for road ',

/' '0.)) J736

392

(@.E@ sec

)5 Adding (.C sec each to the clearance amber and (.C sec to the inter8green period for each

phase

Total cycle time re3uired 4(K'0.))K(5K4(K(@.E@K(5

0C.'' sec%ignal cycle time may be conveniently made in multiple of 0 sec.

%o the cycle time will be 00 sec.The e"tra (.0 sec. per cycle may be assigned to the green time of road ' and ( as '.0 and '.C sec.

respectively.

/' (@.E@ K '.0 )C.(@ L )' sec.

/( '0.)) K '.C '.)) L ' sec.


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-5 Vehicles arrivals per lane cycle on road '

736

55

').)@ #!$

9inimum green time for clearing vehicles on the road ' K 4').)@8'5 ( )C.E sec.Vehicles arrivals per lane cycle on road (

392

55

E.'( #!$

9inimum green time for clearing vehicles on the road ( K 4E.'(8'5 ( '@.(0 sec.

As the green time designed above for two roads by pedestrian crossing criteria are having values

high, thus the above values can be accepted as they are alright and minimum.

05 Total lost time per cycle 4amber time K inter8green time K time lost for initial delay of firstvehicle5

>or two phase 4(K(K-5J ( ' sec.

>rom I!1 D)8'D@0

The total lost time per cycle is e3ual to the total

amber time per cycle i.e. @ sec, plus - sec. reaction time for first vehicle in phase ', plus - sec

reaction time for first vehicle in phase (, i.e. e3ual to total ' sec.

%aturation flow 0(0 J : #!$ per hour :here,

: width of the approach measured from kerb to the inside of the central median or mentioned

centre line of the approach.

The width lesser from 0.0 m, the values for saturation flow is taken from the table below1

%aturation flow for critical approach for road ' (00C K40∗5

5 (0DC #!$2hour


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%aturation flow for critical approach for road ( ((0C K40∗4.75

5 ((@@ #!$2hour

y'

736

2590

C.(@

y( 392

2288

C.'E

? y' K y(? C.(@ K C.'E

? C.-0

The :ebsterHs formula for optimum cycle time

o

1.5 L+5

1−Y C

:here,

!o optimum cycle length in seconds

total lost time per cycle

? volume2 saturation flow for critical approach in each phase.

!o 1.5 L+5

1−Y

!o 1.5∗16+5

1−0.45

!o 29

0.61

!o 0(.E( sec

Thus the total cycle time of 00 sec is acceptable.

CONCL"S!ON

+y studying the road traffic of the city we analyzed that the major accident cause is

collision of vehicles at the intersections. The collision may be rear shunt on approach to junction,

right angled collision, principle right turn collisions and pedestrian collision. These collisions can

be avoided if proper design of signal is done at the intersection so that the main objective of the

dissertation is to provide better and safe movement of traffic through signal design at


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the intersection of the Vidisha city is satisfied. The signal is designed as per I! guidelines so

that the signal can justify the proper movement of the traffic.The effect of the signal design can be seen in reduction of accident cause by which the reduction

in fatal injuries at the intersection. Thus provide a better and safe movement of the

traffic. The signal design can also helps the pedestrian to cross the road safely. The signal timing

plays an important role in traffic movement. Thus the timing of the signal should be such that

it does not cause delay to the vehicles. If the timing is causing e"tra delay to the vehicles than the

driver will disobey the signal, resulting in cause of accident. Thus the signal timing should justify

the movement of vehicles so that e"tra delay by the 6& signal will not affect the total

journey time.

REFERENCES

M'N I!8D)1'D@0 F/uideline on &esign and Installation of oad Traffic %ignalsG#M(N Ousto ;hanna ew age #ublication.

M)N .. ;adiyali khanna publications.

M-N oad accident in India /overnment of India 9inistry of oad Transport And

traffic signals using irc

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