road lighting manual - dot

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ROAD LIGHTING MANUAL

DRAFT FINAL DOCUMENT

2013


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DraftFinalDocument Page i March2013

March 2013

Draft Final Document

Abu Dhabi Department of Transport

Al Bateen Towers

PO Box 20

Abu Dhabi, United Arab Emirates

Copyright 2012, by the Abu Dhabi Department of Transport. All Rights Reserved. This

document, or parts thereof, may not be reproduced in any form without written permission ofthe publisher.


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TABLE OF CONTENTS

Table of Contents ................................................................................................................ ii

List of Figures ................................................................................................................... vii

List of Tables ..................................................................................................................... vii

Foreword .......................................................................................................................... viii

1 Introduction .................................................................................................................. 1

1.1 Overview ................................................................................................................. 1

1.2 Purpose and Scope ................................................................................................ 1

1.3 Application of this Document ................................................................................... 1

1.4 Content and Format ................................................................................................ 2

2 PURPOSE OF ROADWAY LIGHTING .......................................................................... 3

3 LIGHTING DESIGN PROCESS ..................................................................................... 4

3.1 Lighting Design Steps ............................................................................................. 4

3.1.1 Initial Study ...................................................................................................... 4

3.1.2 Selecting Poles ................................................................................................ 5

3.1.3 Locating the Poles ........................................................................................... 5

3.1.4 Verifying the Lighting Design Criteria ............................................................... 6

4 LIGHTING GUIDELINES ............................................................................................... 8

4.1 Objectives ............................................................................................................... 8

4.2 Lighting Guidelines for Freeways ............................................................................ 8

4.2.1 Continuous Freeway Lighting ........................................................................... 8

4.2.2 Complete Interchange Lighting ........................................................................ 9

4.2.3 Partial Interchange Lighting ........................................................................... 10

4.2.4 Special Considerations .................................................................................. 11

4.3 Lighting Guidelines for Streets and Roadways Other Than Freeways ................... 11

4.4 Lighting Guidelines for Other Facilities .................................................................. 12

5 TYPES OF LIGHTING SYSTEM CONFIGURATION ................................................... 14

5.1 Lighting of Traffic Routes ...................................................................................... 14

5.1.1 General .......................................................................................................... 14

5.1.2 Design Considerations ................................................................................... 14

5.1.3 Lighting Standards ......................................................................................... 15

5.2 Lighting of Bridges and Elevated Roads ............................................................... 17


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5.2.1 General .......................................................................................................... 17


5.2.3 Lighting Standard ........................................................................................... 18

5.2.4 Arrangement of Luminaires ............................................................................ 19

5.3 Lighting of Subsidiary Roads and Associated Areas, Public Realms, and Cycle-

Ways 20

5.3.1 General .......................................................................................................... 20


5.3.3 Conditions of Subsidiary Roads and Associated Areas, Public Realms, and

Cycle-Ways .................................................................................................................. 21



5.4 Lighting of Conflict Areas ...................................................................................... 25

5.4.1 General .......................................................................................................... 25


5.4.3 Conflict Area Conditions ................................................................................ 26

5.4.4 Conflict Areas Lighting Standard .................................................................... 26


5.5 Lighting Area around Aerodromes, Railways, Harbours, and Navigable Inland

Waterways ...................................................................................................................... 27

5.5.1 General .......................................................................................................... 27



5.6 Lighting of Tunnel ................................................................................................. 29

5.6.1 General .......................................................................................................... 29

5.6.2 Tunnel Topology ............................................................................................ 29

5.6.3 Traffic and Roadway Geometry...................................................................... 30

5.6.4 Visibility at the Tunnel Approach .................................................................... 31

5.6.5 Eye Adaptation at the Tunnel Approach ......................................................... 32



5.6.8 Electrical Power Supply and Distribution ........................................................ 35

5.7 Lighting of Exterior Environment ........................................................................... 35


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5.7.1 General .......................................................................................................... 35


5.7.3 Design Standard ............................................................................................ 39

5.8 Sign Lighting ......................................................................................................... 41

5.8.1 General .......................................................................................................... 41


5.8.3 Sign Lighting Standard ................................................................................... 42


6 LIGHTING EQUIPMENT .............................................................................................. 45

6.1 Lanterns ................................................................................................................ 45

6.1.1 1000 Watt High Pressure Sodium Lanterns for 30.5-Metre High Poles .......... 46

6.1.2 Light Emitting Diode (LED) Luminaires .......................................................... 47

6.1.3 LED Luminaires for Tunnel and Underpass Areas ......................................... 50

6.1.4 Basis of Lantern Acceptance ......................................................................... 50

6.1.5 Adaptive Lighting (Automatic Dimming Controls) ........................................... 50

6.2 Poles..................................................................................................................... 51

6.2.1 Straight Poles ................................................................................................ 516.2.2 Hinged Poles ................................................................................................. 52

6.2.3 Multi-Function Decorative Poles..................................................................... 53

6.3 Conduits ............................................................................................................... 53

6.3.1 Rigid Polyvinylchloride (PVC) Conduit ........................................................... 53

6.4 Conductors ........................................................................................................... 54

6.5 Foundations .......................................................................................................... 54

6.6 Junction Boxes/Chambers .................................................................................... 55

6.7 Service Cabinets ................................................................................................... 55

6.8 Earthing/Lightning ................................................................................................. 55

6.8.1 Earthing System ............................................................................................ 55

6.8.2 Lightening Protection System ........................................................................ 56

7 POWER SUPPLY ........................................................................................................ 57

7.1 Power Source ....................................................................................................... 57

7.1.1 Main Power Supply ........................................................................................ 57

7.1.2 Low Voltage Power Directive ......................................................................... 58


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7.1.3 Solar Power Source ....................................................................................... 59

7.1.4 Electric Circuit Design .................................................................................... 60

7.1.5 Voltage Drops ................................................................................................ 60

7.1.6 Conductor/Cable Determinations ................................................................... 60

8 DESIGN DRAWING DEVELOPMENT ......................................................................... 61

8.1 Required Sheets ................................................................................................... 61

8.2 Preparation of Reference Files.............................................................................. 64

8.3 Preparation of Design Files ................................................................................... 64

8.4 Production of Design Drawings ............................................................................. 64

8.5 Quantity Takeoff and Construction Cost Estimate ................................................. 65

9 DESIGN CHECK LIST ................................................................................................. 66

10 GUIDELINES FOR ROADWAY LIGHTING SYSTEM INSTALLATION ................... 68

10.1 Safety Considerations ........................................................................................... 68

10.2 Pole and Luminaire Installation ............................................................................. 68

10.2.1 Marking of Sites ............................................................................................. 68

10.2.2 Excavations ................................................................................................... 68

10.2.3 Handling of Poles ........................................................................................... 6810.2.4 HPS Installations ........................................................................................... 69

10.2.5 LED Installations ............................................................................................ 70

11 GUIDELINES FOR ROADWAY LIGHTING SYSTEM INSPECTION........................ 74

11.1 General ................................................................................................................. 74

11.2 Elements of Inspection .......................................................................................... 74

11.2.1 Safety Inspections ......................................................................................... 74

11.2.2 Detailed Inspections....................................................................................... 74

12 GUIDELINES FOR ROADWAY LIGHTING SYSTEM MAINTENANCE ................... 76

12.1 Maintenance Factors ............................................................................................ 76

12.1.1 Light Loss Factors (LLF) ................................................................................ 76

12.1.2 Luminaire Dirt Depreciation ............................................................................ 76

12.1.3 Lamp Lumen Depreciation ............................................................................. 77

12.1.4 Equipment Factor (EF) ................................................................................... 77

12.2 Support Structure Maintenance............................................................................. 77

12.3 Electrical Distribution and Control System Maintenance ....................................... 78


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12.4 External Factors .................................................................................................... 78

Cited References ............................................................................................................... 79

Other References .............................................................................................................. 80

Glossary ............................................................................................................................ 81

Index .................................................................................................................................. 87


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LIST OF FIGURES

Figure 1-1: Lighting Design Flow Chart ................................................................................. 7

LIST OF TABLES

Table 4-1: Lighting Guidelines for Continuous Freeway Lighting (CFL) Existing Roads

without Lighting or New Planned Roads ................................................................................ 9

Table 4-2: Lighting Guidelines for Complete Interchange Lighting (CIL) Existing Roads

without Lighting or New Planned Roads .............................................................................. 10

Table 4-3: Lighting Guidelines for Partial Interchange Lighting (PIL) Existing Roads without

Lighting or New Planned Roads .......................................................................................... 10

Table 5-1: Lumination / Illumination Requirements for Traffic Routes .................................. 15

Table 5-2: Illumination Requirements for Overall Public Parks and Public Realm Areas ..... 22

Table 5-3: Illumination Requirements for Specific Public Realm Areas ............................... 23

Table 5-4: Minimum Average Luminance Table .................................................................. 34

Table 5-5: Recommended Daytime Interior Zone Average pavement Luminance (in cd/m2) 35

Table 5-6: Illumination Requirements for Architectural Lighting ........................................... 40

Table 5-7: Illumination Factor for different colours ............................................................... 41

Table 5-8: Average Maintained Levels of Illuminance or Luminance ................................... 43

Table 8-1: Sheets to be Included in Standard Lighting Design Plans .................................. 62


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FOREWORD

.


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1 INTRODUCTION

1.1 Overview

In 2010, the Abu Dhabi Department of Transport commenced with the Unifying and

Standardizing of Road Engineering Practices Project. The objective of the project was to

enhance the management, planning, design, construction, maintenance, and operation of all

roads and related infrastructures in the Emirate and ensure a safe and uniform operational

and structural capacity throughout the road network.

To achieve this objective, a set of standards, specifications, guidelines and manuals were

developed in consultation with all relevant authorities in the Abu Dhabi Emirate including the

Department of Municipal Affairs (DMA) and Urban Planning Council (UPC). In the future, all

authorities or agencies involved in roads and road infrastructures in the Emirate shall

exercise their functions and responsibilities in accordance with these documents. The

purpose, scope, and applicability are clearly indicated in each document.

It is recognized that there are already published documents with similar objectives and

contents prepared by other authorities. Such related publications are mentioned in each new

document and are being superseded by the publication of the new document, except in

cases where previously published documents are recognized and referenced in the new

document.

1.2 Purpose and Scope

The primary purpose of this manual is to establish standards and guidelines for the planning,

design and installation of road lighting within the Abu Dhabi Emirate in order to provide

adequate and uniform lighting of roads and other travel-ways within the public right-of-way.

This manual will establish processes which guides the efficient and effective placement of

road lighting. The use of this manual will also help road lighting designers in streamlining the

design process.

1.3 Application of this DocumentThe manual provides appropriate illumination standards for different types of roadway

facilities (e.g., high speed, low speed), land use characteristics (e.g., urban, rural), footpaths,

cycle-ways, complex roadway geometry (e.g., interchanges), intersections, bridges, and

underpass/tunnel lighting.

The intended target users for this manual are transportation planners, designers,

construction contractors, and the agencies staff responsible for planning, design, operations

and maintenance of road lighting facilities.


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1.4 Content and Format

This manual is divided into twelve main chapters: Each chapter contains subsections that

provide more detailed information about the road lighting process as it pertains to the subject

of each chapter. Each chapter is described briefly below.

Chapter 1 provides an overview and the purpose of the document.

Chapter 2 discusses the purpose of road lighting and its benefits.

Chapter 3 describes the step-by-step design process.

Chapter 4 provides guidelines for the conditions in which road lighting should be considered

for different types of facilities based on certain parameters such as traffic volumes, adjacent

land use, accidents, etc.

Chapter 5 details the different types of lighting system configurations for different facilities

and their illumination requirements.

Chapter 6 establishes guidelines for the selection of types of equipment, including poles,

lanterns, conduits, conductors, foundations, chambers and service enclosures.

Chapter 7 describes power supply requirements that should adhere to local codes and

standards as established by Abu Dhabi Distribution Company (ADDC) and Al Ain

Distribution Company (AADC).

Chapter 8 discusses the process of developing road lighting design drawings and

documents to ensure all design formats are consistent.

Chapter 9 provides a checklist for the designer to ensure the design of the lighting system is

in accordance with DoT standards and guidelines.

Chapter 10 outlines the procedures for the installation of the road lighting system.

Chapter 11 provides guidelines for the inspection of the road lighting system.

Chapter 12 discusses different factors for proper maintenance of the road lighting system.


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2 PURPOSE OF ROADWAY LIGHTING

The primary purpose of roadway lighting is to produce quick, accurate, safe and comfortablevisibility at night or when visibility is low. These qualities of visibility may safeguard, facilitate,

and encourage vehicular and pedestrian traffic. Every designer should provide for those

inherent qualities required by the user. A very important consideration is that of making

streets and roadways useful during hours of darkness as well as during the daytime. Where

good visibility is provided through lighting, efficient night use can be made of the large

investments in roadways and motor vehicles. Thus, the proper use of roadway lighting as an

operative tool provides economic and social benefits to the public including:

Reduction in night crashes

Augmentation of police protection and enhanced sense of personal security

Facilitation of traffic flow

Promotion of business and the use of public facilities during the night hours

This manual includes information on the purpose and impacts of roadway lighting levels,

acceptable styles of lighting poles and fixtures, priority and associated aspects of roadway

lighting such as designing with reducing light pollution in mind.


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3 LIGHTING DESIGN PROCESS

Industry development and general experience on road lighting has resulted in a reasonablywell-developed technique for the design of lighting systems. Accepted methods exist for

achieving lighting conditions known as either level of illuminance or level of luminance.

These methods permit ready analysis of alternative lamps, luminaires, mounting height,

luminaire spacing, energy consumption, etc., to determine a preferred design. As more

efficient light sources and better luminaires are developed, they are incorporated into current

designs.

The design of a roadway lighting installation is a process of applying known or specified

photometric characteristics of selected lamp-luminaire combinations. Since illuminance

considers only incident light, photometric information about the luminaire and proximity and

orientation to the pavement surface is the only required information. To achieve the desiredluminance, pavement reflectance should be known. A trial-and-adjust process of assumed

luminaire locations is used in making calculations of either the average amount of

illuminance or the average luminance over the roadway. For each lamp-luminaire

combination, the manufacturers data will show photometric performance of luminaires.

These data can be used, along with pavement reflectance characteristics in the case of

luminance, to theoretically determine luminaire positions to produce the desired luminance

over the given pavement area. It is important to test luminaires to determine that luminaires

supplied match the photometric performance of luminaires used in the design process.

Calculations are performed by computer programs designed for lighting design purposes.

The values of the average amount of illuminance or luminance and variations in the average

level are the basis of design.

3.1 Lighting Design Steps

There are four steps to roadway lighting design: an initial study to become familiar with the

project and design requirements, selection of the general types of luminaire and poles to be

used, locating the poles, and performing appropriate computations to assure conformance to

design criteria. During each step, Estidama assessment should be conducted to ensure a

sustainable design.

Figure 1-1 presents a flow chart that shows the process to be followed by the design

engineer looking to have either an existing roadway lighting upgrade or new roadway

lighting.

3.1.1 Initial Study

Study the project including the roadways, freeways, the freeway interchanges, etc. and

identifying the following features:

Name of different segments of the project including street, ramps, bridges,

overpasses, tunnels, etc.


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Identify diverging lanes, converging lanes, abrupt curves, accelerating, and

decelerating traffic lanes. These locations will need careful attention.

Identify segments of the project where the road is categorized as major, collector,and local streets including pedestrian activity and crossing.

Identify structures, walls, fences, ditches, water ponds, lakes, or rivers.

Identify pedestrian walkways, sidewalks, and bikeways.

Identify any hospitals, residential areas, airports, observatories, industrial,

commercial zones, or any other critical locations close by.

Identify public right of way.

Identify the elevations of the different roads, ramps, overpass, etc. on the project.

This is especially important when the use high mast fixtures for lighting roads at

different elevations or the use of offset lighting are intended.

Determine the width of the different pavements, shoulders, medians, barriers, etc. Visit the project site to get a feeling for the area. Is the project an extension of an

existing area with existing patterns and/or existing types of fixtures that need to be

matched?

Identify the clear zones where the poles will be located. Try to locate the poles

behind guardrails, girders, and ditches. Consider fixtures that allows for large

setbacks.

Identify any trees nearby, their types and their sizes for potential growth. Consider

moving some of the poles to avoid obscuring the lights, or cutting the trees.

Establish the lighting criterion for each segment of the projects. Different road

classifications have different criterion.

3.1.2 Selecting Poles

The primary selection of the poles will depend on several factors, such as width of the

road, and the location of the project:

Consider shorter poles for narrower roads, taller poles for wider roads use short

poles close to residential areas.

Select poles designed for roadway applications.

For safety, and unless poles are behind walls, guard rails, or ditches, consider

selecting poles of break-away design, even if the poles will be located well off theroad.

Select the poles to withstand the wind force in the project area.

Pole foundation and/or mounting design must be considered carefully and

coordinated in the overall design of the roadway, bridges, etc.

Consider selecting aesthetically appealing poles suitable for the project,

especially in downtown and historical areas.

3.1.3 Locating the Poles

In selecting the pole locations, avoid the clear zone of the roadway and behind

manmade or natural deflectors. Install the poles behind the shoulder of the road. Stayaway from signs and traffic signal lights. Additionally, consider the hazard of servicing


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poles. If the poles are located in the median, verify that the median is large enough to

install the poles, and the shoulders are large enough to accommodate maintenance.

3.1.4 Verifying the Lighting Design Criteria

Most designers now use commercially available software to model the lighting design, to

locate the fixtures and perform lighting calculations. There are usually three criteria

considered in roadway lighting: luminance, illuminance, and small target visibility.

Luminance, in Candela/metre2 (Cd/sq m) is a measure of how bright the roadway

is, taking into consideration the amount of light reflected from the pavement.

Illuminance, in footcandle/Lux (fc/Lux), is a measure of the amount of light

incident on the roadway.

Small target visibility is affected by factors such as the luminance of the target,

the luminance of the immediate background, the adaptation level of the adjacent

surroundings, and the disability glare. Small target visibility is a weighted

average.

These criteria are typically computed for a discrete area (zone) of interest. Of more

interest that specific values are the minimum, maximum, and average values within the

zone and the ratios of average-to-minimum and maximum-to-minimum. The calculated

value should be within the recommended design criterion.


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Figure 1-1: Lighting Design Flow Chart


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4 LIGHTING GUIDELINES

4.1 ObjectivesThe primary purpose of lighting guidelines is to assist administrators and designers in

evaluating locations for lighting needs and selecting locations for installing lighting. These

guidelines give conditions that should be satisfied to justify the installation of lighting.

Meeting these lighting guidelines does not obligate the relevant authorities to provide lighting

or participate in its cost. Conversely, local information in addition to that reflected by the

guidelines, such as roadway geometry, ambient lighting, sight distance, signing, crash rates,

or frequent occurrences of weather changes, may influence the decision to install lighting.

4.2 Lighting Guidelines for Freeways

Lighting guidelines for freeway lighting are described in three separate categories:

Continuous Freeway Lighting

Complete Interchange Lighting

Partial Interchange Lighting

The cases discuss warranting conditions based on average daily traffic (ADT) volumes,

roadway geometry, and night-to-day crash rates.

This section summarizes available conditions for the selection of those sections of freeways

on which fixed source lighting may be necessary. These guidelines may be applied toroadways other than freeways, as practicable. Additionally, the new roads that do not meet

the guidelines in the first few years of operation but if there are indications that any of the

guidelines will be fulfilled within five years after the opening of the project to traffic, roadway

lighting shall be provided on new roads.

4.2.1 Continuous Freeway Lighting

A continuous lighting system provides relatively uniform lighting on all main lanes and direct

connections, and complete interchange lighting of all interchanges within the section.

Frontage roads are not normally continuously lit. The lighting units may be conventional

luminaires or high mast assemblies or both.

Continuous lighting may be necessary under one of the conditions described in the following

table.


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Table 4-1: Lighting Guidelines for Continuous Freeway Lighting (CFL) ExistingRoads without Lighting or New Planned Roads

Case Guidelines

CFL-1Sections in and near cities where the existing ADT (for existing roads) orprojected five-year ADT (for new roads) is 30,000 or greater.

CFL-2Section where three or more successive interchanges are located with anaverage spacing of 2 km or less, and adjacent areas outside the right-of-way are substantially urban in character.

CFL-3

Sections of 3 kilometres or more passing through a substantiallydeveloped suburban or urban area in which one or more of the followingconditions exist:

a. Local traffic operates on a complete street grid having some form ofstreet lighting, parts of which are visible from the freeway.

b. The freeway passes through a series of developments (e.g.residential, commercial, industrial, civic areas, colleges, parks,terminals, etc.) which includes facilities (e.g., roads, streets, parkingareas, yards, etc.) that are lit.

c. Separate cross streets, both with and without connecting ramps,occur with an average spacing of 1 kilometre or less, some of whichare lit as part of the local street system.

d. The freeway cross section elements (e.g. median, shoulders) aresubstantially reduced in width below desirable sections used inrelatively open country.

CFL-4

Sections where the ratio of night to day crash rate is at least two times theEmirate average for all unlit similar sections for existing roads, and a studyindicates that lighting may be expected to result in a significant reductionin the night crash rate. This case is not applicable for new roads.

4.2.2 Complete Interchange Lighting

Complete interchange lighting is defined as a lighting system that provides relative uniform

lighting within the limits of the interchange, including:

Main lanes

Direct connections

Ramp terminals

Frontage road or crossroad intersections.

Complete interchange lighting may be warranted under one of the conditions described in

the following table.


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Table 4-2: Lighting Guidelines for Complete Interchange Lighting (CIL) ExistingRoads without Lighting or New Planned Roads

Case Guidelines

CIL-1

Where the total existing ADT (for existing roads) or projected five-yearADT (for new roads) ramp traffic entering and leaving the freeway withinthe interchange area exceeds 10,000 for urban conditions, 8,000 forsuburban conditions, or 5,000 for rural conditions.

CIL-2Where the existing ADT (on existing crossroad) or projected five-year ADT(on new crossroad) exceeds 10,000 for urban conditions, 8,000 forsuburban conditions, or 5,000 for rural conditions.

CIL-3

Where existing substantial commercial or industrial development that is lit

during hours of darkness is located in the immediate vicinity of theinterchange, or where the crossroad approach legs are lit for 1 kilometreor more on each side of the interchange.

CIL-4

Where the ratio of night to day crash rate within the interchange area is atleast 1.5 times the Emirate average for all unlit similar sections for existingroads, and a study indicates that lighting may be expected to result in asignificant reduction in the night crash rate (this case is not applicable fornew roads).

4.2.3 Partial Interchange Lighting

Partial interchange lighting is defined as a lighting system that provides illumination only at

decision making areas of roadways including:

Acceleration and deceleration lanes

Ramp terminals

Crossroads at frontage road or ramp intersections

Other areas of night-time hazard

Table 4-3: Lighting Guidelines for Partial Interchange Lighting (PIL) Existing Roads

without Lighting or New Planned Roads

Case Guidelines

PIL-1

Where the total existing ADT (for existing roads) or projected 5-year ADT(for new roads) ramp traffic entering and leaving the freeway within theinterchange area exceeds 5,000 for urban conditions, 3,000 for suburbanconditions, or 1,000 for rural conditions.

PIL-2Where the ADT on the freeway through traffic lanes exceeds 25,000 forurban conditions, 20,000 for suburban conditions, or 10,000 for ruralconditions.

PIL-3Where the ratio of night to day crash rate within the interchange area forexisting roads is at least 1.25 times the Emirate average for all unlit similarsections, and a study indicates that lighting may be expected to result in a


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significant reduction in the night crash rate (This case is not applicable fornew roads).

4.2.4 Special Considerations

Where there is continuous freeway lighting, there should also be complete interchange

lighting. When continuous freeway lighting is warranted, but not initially installed, partial

interchange lighting is considered justified under the continuous freeway lighting guidelines

CFL-1 or CFL-2. This would preclude the requirements of satisfying the partial interchange

lighting guidelines PIL-1 or PIL-2.

Where complete interchange lighting is warranted, but not initially fully installed, a partial

lighting system that exceeds the normal partial installation in number of lighting units isconsidered justified.

Lighting of crossroad ramp terminals is necessary regardless of traffic volumes, where the

design requires the use of raised channelizing or divisional islands, or where there is poor

sight distance.

It may be desirable to provide fixed source lighting on long bridges in urban and suburban

areas even though the approaches are not lit. On bridges without full shoulder, lighting

enhances both safety and utility of the bridges. Where bridges are provided with sidewalks

for pedestrian movements, lighting is necessary for pedestrian safety and policing.

4.3 Lighting Guidelines for Streets and Roadways

Other Than Freeways

Urban and rural conditions, traffic volumes (both vehicular and pedestrian), intersections,

turning movements, signalization, channelization, and varying geometrics are factors that

should be considered when determining the lighting needs of streets and roadways other

than freeways. Consider the following when assessing the lighting needs:

Urban Roadways and Intersections Lighting shall be provided along all roadways and

intersections that are located in urban areas.

Rural Intersections Lighting shall be provided at rural intersections that meet any one of

the following conditions:

There are three or more crashes occurring during conditions other than daylight.

The intersection is signalized and there have been, in the past year, five or morereported night-time crashes and there is a day-to-night crash ratio of less than 2.0.

Substantial night-time pedestrian volume exists.

Less than desirable alignment exists on any of the intersection approaches.

The intersection is an unusual type requiring complex turning manoeuvres.


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Commercial development exists in the vicinity which causes high night-time trafficpeaks.

Distracting illumination exists from adjacent land development. Recurrent for or industrial smog exists in the area.

Rural Areas - Lighting of spot locations in rural areas should be provided whenever the

driver is required to pass through a section of road with complex geometry or raised

channelization.

High Conflict Locations - Lighting should be provided along roadway sections with high

vehicle-to-vehicle interactions (e.g., sections with numerous driveways, significant

commercial or residential development, high percentage of trucks). Lighting generally

improves traffic safety and efficiency at such locations.

Night-to-Day Crash Ratio - Lighting should be provided at locations or sections of roadways

where the night-to-day ratio of crash rates is higher than the Emirate average for similar

locations, and a study indicates that lighting may be expected to significantly reduce the

night crash rate. The number of night-time crashes also should be evaluated.

4.4 Lighting Guidelines for Other Facilities

Bridges - Bridges are generally considered to be part of the roadway and, as such, do not

require any special lighting. Therefore, roadway lighting on bridges shall be warranted as

part of the regular roadway lighting.

Roadway lighting may also be considered on bridges and their approach ramps for aesthetic

purposes or where one or both of the following situations exist:

Sag or crest vertical curves exist where the roadway cannot be illuminated by vehicle

headlights for a safe stopping sight distance (SSSD).

Shoulder widths are less than 3 metres.

Tunnels - Tunnels should have sufficient illumination during all hours so that vehicles

inside the tunnel may be seen by approaching motorists. All interior walls and ceilings of

tunnels to be lit should be painted or tiled in a light colour.

Both night-time and day-time illumination shall be provided for long tunnels having a portal-

to-portal length greater than the minimum stopping sight distance.

Day-time illumination may be provided for short tunnels (portal-to-portal length less than the

minimum stopping sight distance) if the horizontal-to-vertical ratio is greater than 10:1.

Night-time illumination may be provided for short tunnels if the adjacent roadway is

warranted for lighting.

Pedestrian and Bicycle Facilities Lighting shall be provided for all pedestrian underpasses

and pedestrian tunnel facilities.


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Lighting shall be provided at all bus-stops and crosswalks.

Pedestrian walkway should be illuminated if it is a connection between two roadway facilities

(e.g. between parking areas and rest room buildings at rest areas; between drop-off/pick-up

points and bus loading areas.

Lighting should be provided on walkways and bicycle trails if security problems have been

reported or are anticipated.

Sign Lighting - Most roadway signs are manufactured with reflective sheeting so that, when

illuminated by vehicular headlights, the sign message is reflected back to the driver. Signs

also may be internally or externally illuminated by a direct light source. Note that

conventional roadway luminaires generally do not meet the requirements for external sign

illumination where justified.

In general, provide sign illumination where background lighting obscures the legend of the

sign, the sign is not adequately visible, or there is nearby roadway lighting.

In urban areas, the external illumination of overhead panel signs generally is necessary.

Provide external lighting for all overhead panel signs along lit roadway facilities. Truss-

mounted signs shall be externally illuminated. Cantilever-mounted panel signs on non-lit

facilities shall be illuminated unless directed otherwise. Consider providing external lighting

for overhead panel signs at interchanges or intersections where there exists a high volume

of traffic. If complete interchange lighting exists, provide external lighting for all overhead

panel signs at the interchange.


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5 TYPES OF LIGHTING SYSTEM

CONFIGURATION5.1 Lighting of Traffic Routes

5.1.1 General

The main function of roadway lighting is to improve driver visibility. A well illuminated

roadway increases safety by allowing drivers to identify potential hazards or conflicts. Well

designed lighting allows the driver to quickly recognize roadway features such as alignment,

delineation, intersections, ramps, traffic signs, traffic signals, and pedestrian crossings. The

improved driving environment in turn improves traffic operations, capacity and safety.

5.1.2 Design Considerations

5.1.2.1 Freeways and Expr essw ays

Because freeways and expressways are wide and have higher traffic speeds, general street

lighting requirements are inadequate for freeway and expressway lighting. High lumen lamps

in conjunction with high mast poles shall be used to illuminate large roadway areas and

reduce glare.

5.1.2.2 Interchanges

High mast lighting is ideal for illuminating interchanges and other large areas because theillumination pattern is not confined to the basic driving lanes. High mast lighting illuminates

the entire interchange, creating the same overall view of the area as that perceived in

daylight. High mast poles can be installed in suitably wide medians on multiple-lane

roadways. This type of lighting enhances traffic safety through high visibility, the need for

fewer poles, and greater flexibility in their location.

5.1.2.3 Ar terials and Frontage Roads

Arterials serve moderately high volumes of traffic at lower speeds than freeways and

expressways. Although their primary function is to move and maintain uninterrupted traffic

flow, they frequently have busy at-grade intersections requiring traffic control devices. These

at-grade intersections require greater visibility for traffic signals, signs and the resulting

crossing and turning conflicts.

Also, increased commercial development along arterials means increased pedestrian

movements and possibly the need to accommodate public transportation (taxicabs and

buses). Adequate lighting for pedestrian movements and public transportations frequent

stopping, loading, and unloading of passengers is vital to safety along arterials. Arterial

lighting must also blend with commercial development lighting to avoid combinations which

detract from the overall lighting or result in poor visibility.


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5.1.2.4 Secto r Road s

A sector roads primary function is to provide direct access to adjacent properties. Although

traffic speed is low, traffic volume can be heavy and frequently interrupted especially in

residential and commercially developed areas. Because of increased access to commercial

and private property, sector roads, compared to arterials, must accommodate an even

heavier volume of pedestrian movement. Lighting considerations are much the same as for

arterials.

5.1.2.5 Intersectio n and Pedestrian Cros sin gs

Lighting intersection and pedestrian crossings is of particular concern and must be adequate

for traffic and pedestrian security, as well as meeting environmental objectives. If necessary

for traffic safety, pedestrian security, or aesthetics, the lighting colour should be varied to

define the various elements more clearly. Generally, the illumination level at an intersection

of two at-grade roadways is the sum of the illumination of the two roadways.

5.1.3 Lighting Standards

Table 5-1 summarizes the illumination requirements for various roadways.

Table 5-1: Lumination / Illumination Requirements for Traffic Routes

Roadway

MinimumAverage

Luminance (L)= CD/m2,

Illumination (E)= LUX

Uniformity Ratio(minimum to

average)

LightPole

Height(m)

Freeway &

Expressway

1.5 CD/m2 0.4 Discharge or

LED

30.5

20***

Interchanges 1.5 CD/m2 0.4 Discharge 30.5 **

Major Arterial(Boulevard)

1.3 CD/m2 0.4 LED orEquivalent****

Max 14***

Secondary Arterial(Avenue)


Max 12***

Sector Roads /Ramps

(Street)


Max 10***

Access Lanes 0.5 CD/m2 0.4 LED orEquivalent****

Max 10***

Crosswalks 30 LUX 0.4 LED orEquivalent****

To matchRoad***

Ramp Terminal and

Traffic Conflict Areas

2.0 CD/m2 0.4 To Match Road To Match

Road***


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Roadway

MinimumAverage

Luminance (L)= CD/m2,

Illumination (E)= LUX

Uniformity Ratio

(minimum toaverage)

LightPole

Height(m)

Parking Areas 5-15 LUX

(low to highrisk)

0.4 LED orEquivalent****

Max 10***

Under Bridges To Match Road 0.4 LED orEquivalent****

Source: Lighting Specification, Parks, Public Realm & Architectural Lighting, Emirate of Abu Dhabi, November 1,

2011.

Notes: *On high volume roads, lighting will be upgraded to suit conditions.

**Areas of traffic conflict would have high levels of illumination equal to the sum of values recommended

for each of the intersecting roads.

***Optimum pole heights and spacing arrangement to be selected for the project so that it is designed

for the maximum possible overall luminous and energy efficiency with the fixtures proposed.

****Any equivalent technology to LED proving similar or better illumination performance, energy

efficiency and long-term (minimum 15-year) full life cycle cost analysis comparison undertaken to PAS

55 or similar and which fully meets the requirements of this specification.

Illumination/Lumination levels stated in Table 5-1 represent the lowest average maintained

levels considered appropriate for each kind of roadway or walkway in the various areas.

Illumination/Lumination criteria and calculations are based on the Illuminating Engineering

Society of North America (IESNA) standards modified to meet the higher uniformity and

illumination/lumination levels required by the Municipalities of Abu Dhabi.

The roadways not identified in this manual will use a light source as directed by the relevant

authority in charge of the road or Municipality. Side roads and ramps shall have the same

light sources as the adjacent main roads.

The lanterns shall be mechanically strong and easy to maintain. They shall be of adequate

design to operate at mounting heights of 30.5 meters and able to withstand sustained wind

speeds of 160 kph with 208 kph gusts.

Lanterns shall have optical systems sealed against moisture, dirt and insects, and be

mechanically strong and easy to maintain.

Glare control for the mounting height specified, and cut-off characteristics shall be designed

based on I.E.S. standards.

High mast lighting (30.5- metre poles) shall be used on rural and urban freeways and

expressways with side medians where one row of 14 -metre poles is not suitable. The 30.5 -


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metre poles shall also be used at all interchanges. Wherever possible, high mast lighting

shall be used for ramps.

High mast lighting will be used on main roads only when light height will not substantially

interfere with nearby buildings and Estidama PCRS LC R6 requirements.

LED lighting with a maximum 20- metre pole height shall be used anywhere except where

high mast lighting is used.

5.2 Lighting of Bridges and Elevated Roads

5.2.1 General

This section gives recommendations for the technical and aesthetic considerations of

designing lighting for bridges and elevated roads.


The roadway on a bridge is normally treated the same as other parts of the roadway. An

exception is a very long bridge, which may be lit even though the roadway is not lit at other

locations. The lighting designer should consider placing roadway lighting in advance of the

bridge to allow the drivers eyes to transition into the brighter roadway on the bridge.

Bridges lacking in significant surrounding landscape features or background, or those arched

to create central crests, can create conditions of glare with reduced luminous foreground or

confusing forward scene, each of which reduce the forward view of the driver. Driversapproaching the crest of a bridge can experience glare from lights on and beyond the crest

and have a reduced length of visible lit road before them. Beyond the crest, their forward

view can be confused by the presence of road, vehicle and building lights occurring in the

near and/or distant fields of view. Further technical problems can arise from features

spanned by or in the vicinity of the bridge.

Difficulties are sometimes encountered in obtaining fixings for lighting columns on existing

bridges, and the desired positions might be partially or completely obstructed by services or

features, or the structure might not be strong enough. However, the mechanical loads

imposed on the bridge by road lighting equipment are usually small, even when heavy wind

loads are taken into consideration. On new bridges, the positions for lighting columns and

the location of power supply cables should be decided at a sufficiently early stage in the

design to ensure the provision of suitable space, fixings, and protection for them.

Elevated roads differ from bridges in that they are usually longer, they are often sinuous, and

they often have parallel roads alongside them at lower levels. They also often have slip

roads that join the two levels; they usually carry very heavy traffic and have little room for

maintenance. Elevated roads differ so much from each other that each requires individual

consideration. Maintenance can be very difficult since the closing of lanes for maintenance

vehicle might not be acceptable, and this can be a ruling factor in the lighting design.


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5.2.3 Lighting Standard

The design of lighting for a bridge should consider the character and structure of the bridge

and the surrounding environment. Where bridges carry the road system without significant

change of gradient or direction, it is likely that the lighting system on the bridge approaches

can be continued across the bridge.

5.2.3.1 Elevated Road on Embankment with Paral lel Ground-Level

Roads

When an elevated road is on an embankment with a slope, the bank results in the lower road

will have a vertical and horizontal separation from the upper road. The following lighting

arrangements shall be considered:

1. Masts mounted between the roads: If the overall width of the combined area is

suitable, both roads may be lit by luminaires mounted on masts that are high

compared with the difference in level between the roads. This arrangement has the

advantage of reducing the number of lighting points and glare and simplifying

maintenance.

2. Masts mounted on the outside of the lower road: Where there are steep

embankments or retaining walls, the masts may be mounted on the outside of the

lower road. This has the same advantages as above, but can result in inferior light

utilization.

3. Luminaires mounted on the upper road lighting columns: The luminaires used to

illuminate the upper road can sometimes suffice to light both roads. If this is not thecase, separate luminaires should be mounted on the upper lighting columns at an

appropriate height to illuminate the lower road.

5.2.3.2 Elevated Road on a Viaduc t With Parallel Ground-Level

Roads:

1. Parallel ground-level roads close to and/or partly beneath the viaduct: If the upper

road is lit by luminaires at its sides, their light might reach only part of the lower

carriage way and they can cause an undesirable continuous shadow. Lights mounted

on the underside of the viaduct can offset this problem, although the mounting heightfor such lights is often restricted, and care should be taken to minimize problems with

shadows cast by beams or pillars.

2. Parallel ground-level roads close to or crossing the elevated road: Consideration

should be given to lighting both the upper and lower roads from luminaires mounted

on the outer sides of the lower roads. To achieve this, the mounting height should be

such that the lighting requirements for the upper road are met, without shadows

being cast by the viaduct on the inner sides of the lower road such that the lighting

requirements for the lower road are not met. This solution avoids all lighting

maintenance activity on the elevated road. It might be necessary to provide a special

light distribution designed to control light beyond the limits of the road. If the lighting

requirements for the elevated road cannot be met by the outer luminaires on the

lower road, then luminaires should also be mounted on the elevated road.


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5.2.4 Arrangement of Luminaires

Difficulties are sometimes encountered in obtaining fixings for lighting columns on existing

bridges, and the desired positions might be partially or completely obstructed by services or

features, or the structure might not be strong enough. However, the mechanical loads

imposed on the bridge by road lighting equipment are usually small, even when heavy wind

loads are taken into consideration.

The desirable locations for the lighting units on a bridge should be at abutments and at pier

locations, or at a distance from an abutment or pier not to exceed 25 percent of the length of

the span. This placement of the lighting units reduces the effects of vibration. The light poles

should utilize davit type mast arms and shorter mast arm lengths so that there are no joints

to be weakened by vibration.

Increasing the light pole spacing, or using a staggered pole arrangement to reduce the

roadway illumination to one-third creates the transition zone the average level on the bridge.

This reduced lighting level can be accomplished using the same type and wattage luminaire

installed on the bridge. The length of the transition zone is based on the wet pavement safe

stopping distance.

Lighting poles on bridges should be located within the protection of railings or parapets.

Poles located on the inside of curves of super-elevated bridges may be vulnerable to

collision by trucks overhanging the inside curb line. Luminaires may be located either on top

of or behind bridge railing. Light standards mounted on top of retaining walls will require

special consideration in the retaining wall design.

The bridge designer shall review the structural impact of the proposed pole locations. The

lighting designer shall review and determine compatibility of the new pole locations if any

with the lighting criteria. This iterative process applies to any bridge structure requiring

lighting. The installation of navigation and air obstruction lights are an integral part of the

bridge design. The lighting designer should coordinate electrical service points for the

roadway lighting and navigational/air obstruction lighting.

Lighting columns should, where possible, be mounted over piers and abutments, to render

their height more aesthetically acceptable. With long spans it is sometimes necessary to

have additional lighting columns between piers, but all luminaires should be at the samemounting height. An opposite arrangement may be used to complement the bridge structure,

and can make possible a lower mounting height. A central arrangement appears as a

regularly spaced array of lighting columns from any viewpoint and needs fewer lighting

columns than an opposite arrangement. On a very short bridge, it might be possible not to

have lighting columns on the bridge itself, even if this means a greater mounting height for

the luminaires at either end.


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5.3 Lighting of Subsidiary Roads and Associated

Areas, Public Realms, and Cycle-Ways

5.3.1 General

The main purpose of lighting for subsidiary roads and areas associated with those roads is

to enable pedestrians and cyclists to orientate themselves, to detect vehicular and other

hazards, and to discourage crime against people and property. The lighting on such roads

can provide some guidance for drivers, but is unlikely to be sufficient for revealing objects on

the road without the use of headlights.

The main purpose of lighting public realms and cycle tracks not directly associated with

roads is to show the direction that the route takes, to enable cyclists and pedestrians to

orientate themselves, to detect the presence of other cyclists and pedestrians and otherhazards, and to discourage crime against people and property.


A variety of luminaires are used for lighting public realms and cycle-ways such as post top,

architectural, area and roadway, bollards and wall mounted. The types that are best suited

for a specific application can be determined by comparing luminaire and lamp combinations

to basic considerations, such as:

1. Location of public realms and cycle-ways in terms of distance from roadway

vehicular traffic and the roadway lighting system, and consideration of adjacent areas(i.e., residences and commercial parks)

2. Mounting height restrictions

3. Location requirements of poles and luminaires

4. Illumination requirements (horizontal and vertical)

5. Quality of uniformity requirements

6. Brightness and glare restrictions (per Estidama regarding Communities section LC-

R6: light pollution reduction)

7. Energy requirements (lamps, ballasts, timers, controls, or photocells to control

duration of luminaire operation)

8. Zoning ordinance restrictions9. Effects of light trespass, astronomical light pollution, and spill light

10. Terrain complications

11. Foliage interference

All lighting equipment should complement rather than detract from the appearance of the

area. The general lighting should define the area rather than the traffic route. In urban

centres and public amenity areas, the needs are twofold. The first criterion is the ability to

illuminate the area and objects concerned in the most effective manner possible. The

second is the appearance of the lighting equipment. It should be aesthetically pleasing in

itself as well as being in harmony with its surroundings. At all times and especially at night it

should add to the attraction of the urban scene rather than detract from it.


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Colour rendering is important in most aspects of urban centre lighting. In areas of mixed

vehicular and pedestrian traffic the ability to distinguish objects is considerably improved by

the differentiation of colours. This is a benefit both to the public and to the police. The

different colour appearances of light sources can be exploited by the lighting engineer to

bring planned variety to the night-time urban scene. While long life and high efficacy are

important economic factors, other characteristics of the lamp are equally important.

Luminaires and their supports should be regarded as a unit and should be chosen to

harmonize with the area in which they are to be used. Where older style luminaires are

adopted for re-use, due regard should be given to their optical performance and appearance.

If ancillary control gear boxes are necessary, these shall be made as inconspicuous as

possible.

5.3.3 Conditions of Subsidiary Roads and Associated Areas,Public Realms, and Cycle-Ways

The relative balance of the lighting needs for urban centres and public amenity area

depends on the type of traffic among other factors.

1. Primarily vehicular: The appropriate lighting for primarily vehicular areas shall be

defined in terms of average roadway luminance and uniformity. The lighting of public

realms, other pedestrian areas and cycle tracks adjacent to the roadway may need to

be considered separately from that of the roadway.

2. Mixed vehicular and pedestrian: The appropriate lighting class for mixed vehicular

and pedestrian areas shall be defined in terms of horizontal illuminance anduniformity. In some situations it can be appropriate to apply the same lighting levels

to the whole vehicle and pedestrian area, treating it as one relevant area for design

and calculation. In other situations, particularly where separate vehicle and

pedestrian areas are well defined, it can be appropriate to treat the different areas as

separate relevant areas for design and calculation of lighting. Luminaire intensities

should be carefully controlled in order to prevent glare.

3. Pedestrians and cyclists only: In pedestrian areas the lighting should promote

easy movement of pedestrians, attempt to create a feeling of general security and

well-being and attempt to encourage people to visit and make use of the facilities.

Recognition of the behaviour and intentions of other pedestrians is important, and forthis purpose good colour rendering and adequate facial illuminance shall be

provided.

4. Security and safety: The general lighting needs of traffic referred to in most cases

serve the needs of security and safety. Additionally, it is beneficial to utilize any

public lighting installation throughout the hours of darkness rather than simply during

times of major traffic movement. However, higher lighting levels should be chosen at

periods of major traffic movements, and a lower should be considered at other times.

This can be achieved by the variable lighting by switching lamps in multi-lamp

luminaires or by dimming. To provide a sense of security, sufficient vertical

illuminance shall be provided at face level so that it is possible to recognize whether


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a person is likely to be friendly, indifferent or aggressive, in time to make an

appropriate response.

5. Visual appreciation: The use of imaginative lighting can give added interest to

areas that people might wish to see, and can also do much to subdue the less

visually attractive features within an urban environment by highlighting the more

attractive and worthwhile features.

5.3.4 Lighting Standard

5.3.4.1 Ligh t ing of Public Parks and Public Realms Areas

The illuminance requirements for open public realm spaces such as public squares and

parks, are summarized in the tables below for overall and specific public realm areas.

To provide well-lit surroundings for pedestrian ways and cycle-ways through parks, it is

recommended that the area bordering these ways, for a width of two-to-five meters on each

side be lit at levels of at least one-third of that specified for the public realms or cycle-way.

This is also applicable to similar marginal areas such as below grade entrances to building

basements, in areas of dense shrubbery, in gaps between building fronts, and other

locations where night crime is a concern.

Table 5-2: Illumination Requirements for Overall Public Parks and Public Realm Areas

OverallArea Type

Max OverallAverage Area

Illumination (Em)= Lux

UniformityRatio

Light SourceMax Pole/Mounting

Height

Parks 5 N/ALED orEquivalent*

4m/5m**

PublicRealms

7 N/ALED orEquivalent*

4m/5m**


2011.


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Table 5-3: Illumination Requirements for Specific Public Realm Areas

Specific Area, Use,Task or Feature

AverageIllumination(Em) = Lux

UniformityRatio

(min tomax)

LightSource

Notes

Main Pathways 10 0.25LED orEquivalent*

-

Secondary Pathways 5 0.25LED orEquivalent*

-

Public Squares,Piazzas, and OpenPublic Spaces

15 0.3LED orEquivalent*

Level and designdependent on locationand use

Playgrounds 30 0.3LED orEquivalent*

Localized asnecessary and higherilluminance forspecific equipmentrisk. Avoid excessiveglare

Steps & Hazards 50 0.6LED orEquivalent*

-

Access Points, Exits 50 0.3LED orEquivalent*

Localized treatment

Trees/Bushes 10 -LED orEquivalent* On surfaces

Footbridges 40 0.3LED orEquivalent*

-

Delivery, Rubbish &Refuse area


-

Cycle Racks 10 0.4LED orEquivalent*

-

Signs 100 (vertical) -LED orEquivalent*

Vertical / On sign

Outside AudienceAreas 20 0.4 LED orEquivalent* 1 LUX duringperformance

Performance/StageAreas


-

Water (still) - -LED orEquivalent*

Position lamps toproduce goodreflectance in water

Water (running) - -LED orEquivalent*

Position lamps behindor below and aim tostrike water at obliqueangles or within jets

Focal Points (large) 100 - LED orEquivalent*

-


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Specific Area, Use,Task or Feature

Average

Illumination

(Em) = Lux

UniformityRatio

(min tomax)

LightSource

Notes

Focal Points

(small)200 -

LED orEquivalent*

-

Illuminating a Flagover a DarkBackground

150 -LED orEquivalent*

-

Illuminating a Flagover a BrightBackground


-

Clocks: DarkSurroundings, LightingSurface

100 - LED orEquivalent*

-

Clocks: LightSurroundings, DarkSurface


-


2011.

Notes: Pole/mounting heights and spacing arrangements shall be selected for the project so they are designed

for the maximum possible overall effect and efficiency with all the fixtures proposed and to suit the overall

landscaping, finishes and aesthetic of the project.

* Any equivalent technology to LED proving similar or better illumination performance, energy efficiency and long-

term (minimum 15-year) full life cycle cost analysis comparison undertaken to PAS 55 or similar and which fully

meets the requirements of this specification.

The contribution from lighting produced by nearby store fronts, signs, and private sources

should not be included when determining whether a public realms or cycle-way has sufficient

lighting. These lit elements add significantly to the feeling of safety and security and the

perception of brightness. Consequently, they should be encouraged. However, rows of large

trees whose foliage might interfere with the transmission of light to the public realms or

cycle-ways should be considered in establishing design criteria for each location. Trees that

are in conflict with the lighting design can be pruned and thinned under the guidance of a

licensed, professional arborist, so as to allow for the passage of light through the branches

while maintaining the health, natural habitat, and form of the trees. For areas that are to be

newly planted, the locations and species of the trees must be coordinated with the lighting

design to prevent future conflicts.


Although lighting systems are used primarily at night, they are present and visible during

daylight hours and, therefore, appearance is an important consideration. The designer

should maintain the quality of a lighting system through consideration of the following

characteristics:


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1. The lighting system should be resistant to vandalism and easy and inexpensive to

maintain or repair.

2. The luminaires should be resistant to inclement weather conditions, discolouration,

and corrosion. They should be easily accessible for re-lamping and maintenance.

3. The luminaires should be located so they are not easily damaged by maintenance

and service vehicles.

The designer should be equally concerned that stray light does not intrude into adjacent

residential areas. Any significant stray or spill light is often unwelcome and sometimes

prohibited by local ordinances.

5.4 Lighting of Conflict Areas

5.4.1 GeneralConflict areas occur whenever vehicle streams intersect each other or run into areas

frequented by pedestrians, cyclists, or other road users, or when there is a change in road

geometry, such as a reduced number of lanes or a reduced lane or lane width. Their

existence results in an increased potential for collisions between vehicles; between vehicles

and pedestrians, cyclists, or other road users; or between vehicles and fixed objects. Parking

areas and toll-stations are also regarded as conflict areas.

The lighting should reveal the existence of the conflict area, the position of the curbs and

road markings, the direction of the roads, the presence of pedestrians, other road users, and

obstructions, and the movement of vehicles in the vicinity of the conflict area. Where nolighting is otherwise provided on a road leading to or leaving the conflict area, the selected

lighting class should be installed for a stretch long enough to provide about five seconds of

driving distance at the expected traffic speed.


In any conflict area, glare should be at least as well controlled as on the approach roads, as

the conflict area situation increases the visual demands on the driver.

5.4.2.1 Junctions

The decision regarding positioning of lighting poles and luminaires should be made after

consideration of the lines of traffic flow, the sight lines for merging flow, and the areas of

possible collisions. The lighting at a junction should be related to the need of drivers

approaching the junction to see vehicles approaching from other directions.

5.4.2.2 Roundabouts

The arrangement and character of the lighting may be distinctive, and thus assist the

warning signs in providing reliable warning of the roundabout. The lighting should reveal the

form, direction and edges of the travel lane all the way around the roundabout, with special

emphasis on the central and other traffic islands. Mini-roundabouts, particularly those of the

ghost island type, or those that have been located relatively remote from approach road give


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way lines, can be difficult to see. Luminaires should, where possible, be sited to reveal the

island.

5.4.3 Conflict Area Conditions

5.4.3.1 Junctions

The lighting at a junction should reveal the positions of curbs and road markings, the

directions of roads, the presence of any pedestrians or obstructions, and the movement of

any vehicles in the vicinity of the junction.

5.4.3.2 Roundabout

The lighting provided at a roundabout should enable the driver to see clearly any traffic to

the right at the preceding entry or entries and traffic already on the gyratory system of theroundabout. The lighting shall also enable the driver to have adequate forward vision, when

on the roundabout, to see traffic entering from the left and to decide whether it is safe to

proceed.

A roundabout presents a diversion to the direct flow of traffic and should be revealed as

such. Lighting shall assist in making drivers aware of the roundabout ahead and enable

them to recognize it in ample time.

5.4.3.3 Traffic Island

To minimize delays and reduce the risk of accidents, the layout of junctions can includetraffic islands or their equivalent in roadway markings. These islands are often associated

with diverging traffic lane markings with suitable directional arrows or other instructions. To

ensure efficient working, markings, as well as other features of the junction, shall be clearly

visible to approaching driver.

5.4.3.4 Pedestrian Cros sings

Pedestrian crossings are intended to include both zebra crossings and signal-controlled

crossings.

5.4.4 Conflict Areas Lighting StandardSee Table 5-1 for the minimum luminance requirements for conflict areas.


The clearance between the lighting pole and the travel lane shall be no less than the

minimum distance recommended in the Right of Way Utility Distribution Manual A11 (DOT-

MR-D10). The position of the luminaires around the periphery of a roundabout is not as

critical in relation to the line of the curb as it is on straight roads, so the luminaires

themselves may be set back provided the requirements of the selected lighting class are met

within the defined conflict area.


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Mounting height shall generally be uniform throughout a conflict area. It should not normally

be less than that on any approach road, but may be increased if the number of lighting

columns is thereby reduced.

5.5 Lighting Area around Aerodromes, Railways,

Harbours, and Navigable Inland Waterways

5.5.1 General

This section gives additional guidance on road lighting within areas around aerodromes,

railways, harbours and navigable waterways. Such lighting can affect the safe use of these

areas.

When the potential impact of a new road lighting installation is assessed at the design stage,consideration should be given to the modes of transport that could be affected.

Consultation should be carried out with all appropriate authorities regarding any special

provision that are necessary for a new road lighting installation. Provision should be mutually

acceptable and fully documented for incorporation at the design stage.

Any lighting that interferes with clear vision and the ability to recognize signals of transport

operators should be eliminated. Interference can be caused by:

Disability glare from luminaires or installations.

Variations in contrast and reflected lighting. Lighting of the same colour and pattern as signal lights.


5.5.2.1 Aerodrome

Light can endanger aircraft at any following instances:

The intensity causes glare in the direction of an approaching aircraft.

The colour (e.g., advertising signs) causes it to be mistaken for an aeronautical light.

Viewed from the air, lights make a pattern (e.g., a row of street lights) similar to anapproach or runway lighting pattern.

The overall amount of illumination near the approach to a runway detracts from the

effectiveness of the visual aids provided by the aerodrome for use by aircraft,

particularly in poor visibility conditions.

Road lighting can present a hazard due to the effect of lighting upon the pilots visual picture

or due to the creation of physical obstacles within the airspace manoeuvring area around the

aerodrome. A road lighting scheme could prejudice the safe movement of aircraft on either

or both grounds. Each issue should be addressed separately and appropriate measures

should be taken to minimize any hazards identified.


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The areas where structures such as lighting poles and masts used for road lighting schemes

can affect safe use of an aerodrome are called obstacle limitation surfaces (OLS). The OLS

forms a complex set of three-dimensional surfaces that extend upwards and outwards from

the runways(s) of the associated aerodrome. The OLS completely encircle the aerodrome,

but those surfaces protecting the landing or take-off flight paths can be more limiting than the

rest. Generally, the extent of the OLS varies between 10 kilometres and 15 kilometres,

according to the length of the runways(s).

At any aerodrome the approach, takeoff climb, and transitional surfaces are most

sensitive and should not be infringed. Safeguarding maps define safeguarded areas around

aerodromes, and these maps should be obtained from the aerodrome operator. The local

planning authority and/or the aerodrome operator should be consulted on any road lighting

proposed within this area.

Road lighting can present a hazard due to the effect of lighting upon the pilots visual picture

within the flight paths around an aerodrome. For instance, where a road lies in the vicinity of

an aerodrome that has approach lighting and the road has a similar alignment to the runway,

the road light can present a pattern to the pilot that is similar to the runway lighting. It is

therefore essential to eliminate interferences with the pilots visual picture and road lighting

in the vicinity of aerodromes should be designed to achieve this.

5.5.2.2 Railways

If a road lighting scheme is planned within an area that could affect the safe use of a railway,

the railway track authority should be consulted.

It is essential that any lighting scheme does not affect track visibility for railway operatives.

Colours in a lighting scheme should not conflict or cause confusion with colours used for

signal lights.

5.5.2.3 Harbours

If a road lighting scheme is planned that could affect safe use of a harbour, the local Harbour

Master should be consulted.

Lighting schemes near to and inside a harbour boundary should not interfere with

observation of navigation marks, buoys or ship navigation lights. Lighting should not affect

night vision of mariners in the vicinity of a harbour. Particular consideration should be given

to installation and maintenance of high-mast lighting for dock roads, terminals and other

facilities.

5.5.2.4 Navigab le Inland Waterway s

If a road lighting scheme is planned adjacent to navigable inland waterways, appropriate

local navigation authorities should be consulted.

Lighting schemes adjacent to navigable inland waterways should not interfere with

observation of navigation lights, marks, buoys or signs. Lighting should not affect night vision


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of crews on unit waterways. The distance, angle and intensity of lighting adjacent to inland

waterways should take into account safe navigation of vessels.


Luminaires should be carefully selected and sited to prevent confusion of visual information.

If screening of a light source is necessary, this should be achieved by choice of luminaire. If

external baffles/screens are necessary, they should be designed to be compatible with the

luminaire in terms of fixings and performance.

5.6 Lighting of Tunnel

5.6.1 General

A tunnel is defined as a structure over a roadway, which restricts the normal daytime

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