Traffic Signs Manual Vol 1

THE REPUBLIC OF UGANDA

MINISTRY OF WORKS, HOUSING AND COMMUNICATIONS

ROAD DEVELOPMENT PROGRAM PHASE 2 PROJECT

CONSULTANCY SERVICES FOR THE PRODUCTION OF ENGINEERING MANUALS AND SPECIFICATIONS AS WELL

AS PROVISION OF INSTITUTIONAL SUPPORT

Contract RDP/GN/S008

Traffic Signs Manual

Volume 1

Client: Ministry of Works, Housing & Communications PO Box 10 ENTEBBE

July 2004

Lead Consultant: TRL Limited Crowthorne House Nine Mile Ride Wokingham Berkshire RG40 3GA United Kingdom

Government of Uganda

Ministry of Works, Housing and Communications

Traffic Signs Manual, Volume 1 July 2004

Table of Contents

Volume 1

A. FOREWORD ..............................................................................................................1

B. INTRODUCTION ........................................................................................................2 B.1 Purpose ......................................................................................................................2 B.2 Background ................................................................................................................2 B.3 Preliminaries ...............................................................................................................3

C. THE CONTENTS OF THE MANUAL ..........................................................................4 C.1 Overview .....................................................................................................................4 C.2 Reference Numbers ....................................................................................................5

D. TRAFFIC SIGNS ........................................................................................................6 D.1 General Purpose of Traffic Signs ................................................................................6 D.2 Classification of Traffic Signs ......................................................................................7 D.3 Traffic Sign Sizes ........................................................................................................8 D.4 Siting and Mounting of Traffic Signs ............................................................................8 D.5 Warning Signs .......................................................................................................... 13 D.6 Regulatory Signs ...................................................................................................... 18 D.7 Guidance Signs ........................................................................................................ 22 D.8 Information Signs ...................................................................................................... 26 D.9 Supplementary Plates ............................................................................................... 28 D.10 Sign Materials and Manufacture ............................................................................... 30 D.11 Maintenance of Traffic Signs ..................................................................................... 32

E. ROAD MARKINGS ................................................................................................... 34 E.1 Purpose and Classification of Road Markings ........................................................... 34 E.2 Longitudinal Markings ............................................................................................... 35 E.3 Transverse Markings ................................................................................................ 37 E.4 Other Markings ......................................................................................................... 37 E.5 Marking Materials ..................................................................................................... 39 E.6 Reflective Road Studs .............................................................................................. 40

F. TRAFFIC SIGNALS.................................................................................................. 41 F.1 Purpose and Classification of Traffic Signals ............................................................ 41 F.2 Traffic Signals ........................................................................................................... 42 F.3 Pedestrian Signals .................................................................................................... 45 F.4 Traffic Signals at Railway Crossings ......................................................................... 46

Volume 2 Appendices

Appendix 1 The Design of Text-based Traffic Signs

Appendix 2 Layout of Traffic Signs and Markings in Typical Locations

Appendix 3 Sign Pages



Traffic Signs Manual, Volume 1 July 2004

Tables

Table B.1 Traffic speed classes used in the Manual ................................................................... 3 Table B.2 Functional road categories .......................................................................................... 3 Table D.1 Basic traffic sign sizes ................................................................................................. 8 Table D.2 Visibility distance requirements................................................................................... 9 Table D.3 Siting and sizes of standard warning signs ................................................................. 13 Table D.4 Sizes of standard regulatory signs .............................................................................. 18 Table D.5 Siting of advance direction signs ................................................................................ 22 Table D.6 Letter sizes for guidance signs ................................................................................... 23 Table D.7 Lettering size on text-based supplementary plates .................................................... 28 Table E.1 Spacing of reflective road studs .................................................................................. 40 Table F.1 Interpretation of traffic signals at intersections ........................................................... 43 Table F.2 Interpretation of pedestrian signals ............................................................................. 45

Figures

Figure C.1 Overview of the contents of the Traffic Signs Manual ................................................ 4 Figure D.1 Overview of traffic signs .............................................................................................. 7 Figure D.2 Heights and clearances .............................................................................................. 10 Figure D.3 Alternative methods of mounting supplementary plates ............................................. 11 Figure D.4 Signs on a yellow backing board ................................................................................ 11 Figure D.5 Angle of the sign plate ................................................................................................ 12 Figure F.1 Standard design of signals .......................................................................................... 42 Figure F.2 Alternative designs of pedestrian signals ................................................................... 45 Figure F.3 Standard design of traffic signals at railway crossings ............................................... 46



Traffic Signs Manual, Volume 1 July 2004 Page 1

A. FOREWORD

Traffic signs are all the signs, traffic signals, road markings, and other devices used by the

road authority to regulate, warn or guide traffic. They are essential for the safe, smooth

movement of road traffic. It is important to have a standard set of signs and to use them in a

consistent manner, so that the travellers can become familiar with them.

The Traffic Ordinance of 1951 provides for the Director of Public Works to determine what

signs are to be used on the roads in Uganda, and to keep a pictorial representation of the signs

available for inspection by the public. No record remains of this. Over the years road

engineers have developed some standards, but, because they have never been formalised and

approved, they are not always followed and their legality is in doubt.

In 2003 the Ministry of Works, Housing and Communications appointed consultants to

collaborate with the Ministry‟s engineers and the traffic police in devising a new sign system

for Uganda. Out of this came new Traffic Signs Regulations and this Traffic Signs Manual.

The Traffic Signs Manual provides the technical guidance needed to ensure that the new signs

are designed and placed in a standard way. All road authorities must use the new signs, and

all road users must act on the instructions they give. With everyone‟s co-operation the new

signs can contribute significantly to smooth and safe travel in Uganda.

John M. Nasasira

Minister of Works, Housing and Communications




B. INTRODUCTION

B.1 PURPOSE This Traffic Signs Manual contains technical advice on the use and design of traffic signs in

Uganda. It covers all kinds of signs, including road markings and traffic signals. The Manual

has been written primarily for road engineers who are preparing signing schemes and

designing guidance signs. It may also be helpful to police officers and others who have to

devise traffic management schemes. The adoption of a uniform set of signs will be a big step

forward, but there must also be uniformity in their use and siting. The advice given in the

Manual covers all types of roads and traffic situations, and should be followed by everyone

involved in the signing of roads in Uganda. Nevertheless there will be many situations where

good engineering judgement is required. If further advice is needed, contact the Permanent

Secretary, Ministry of Works, Housing and Communications.

The Manual is made up of two volumes. Volume 1 (this document) describes the new sign

system, illustrates all the signs, and gives advice on sign manufacture and maintenance.

Volume 2 is a set of appendices covering the design of text-based signs, the layout of signs at

intersections and other typical locations, and detailed information on the design and siting of

every sign.

The Traffic and Road Safety (Traffic Signs) Regulations provide the legal basis for the signs

described in this Manual. Refer to the Regulations for the legal meaning of each sign.

The Uganda Police have practical experience of managing the traffic problems on our roads,

and they are also responsible for enforcing the instructions given by the regulatory signs.

Their advice and support will often be helpful in ensuring that new signs are as effective as

possible.

B.2 BACKGROUND The Manual presents a new standard collection of traffic signs, markings and signals for

Uganda. Account was taken of signing practices in the region, primarily Kenya and the SADC

countries, as well as the need for the signs to conform to the provisions of the United Nations

Convention on Road Signs and Signals (the Vienna Convention).

This Manual contains advice on the design and use of traffic signs in view of the present road

traffic situation in Uganda. The Manual will have to be amended and revised as the road

traffic system changes and develops and the knowledge and experience of signing in Uganda

increases. Examples of changes that will lead to a need to further development of the Manual

are:

Introduction of a road numbering system

Introduction of a road classification system

Introduction of freeways and grade separated interchanges.




B.3 PRELIMINARIES

B.3.1 Traffic Speed

Traffic speed is a key factor in determining sign size and siting. By “traffic speed” is meant

the 85th

percentile speed of motor vehicle traffic, i.e., the speed which only 15% of vehicles

exceed. Ideally this should be determined from a speeds survey, but, with practice, engineers

should be able to estimate it well enough from observing the traffic. Note that “traffic speed”

is not the same as the “design speed” of the road, or the “signed speed limit”.

In the Manual the sign sizes are based on the following traffic speed classes.

Traffic speed Typical roads

Up to and including 50 km/h Most urban roads and rural roads of local character

Over 50 km/h and up to and including 80 km/h Major urban roads and most rural roads

Over 80 km/h High-speed rural roads

Table B.1 Traffic speed classes used in the Manual

B.3.2 Functional Road Classification

The colour coding and design of guidance traffic signs are based on the road function.

For the purposes of traffic signing, the rural road network is classified into the following four

categories:

Road category Function

Category A - Primary roads Principal arterial system

Category B - Secondary roads Minor arterial system

Category C - Tertiary roads Collectors

Category D - Feeder roads Local road system

Table B.2 Functional road categories




C. THE CONTENTS OF THE MANUAL

C.1 OVERVIEW In the Traffic and Road Safety Act, section 2 Interpretation, it is stated that:

“traffic sign” means any object or device (whether fixed or portable) for conveying to traffic,

warnings, information, requirements, restrictions or prohibitions of any description specified

by the Minister by regulation and any line or mark on a road for so conveying such warnings,

information, requirements, restrictions or prohibitions;

Consequently ”traffic signs” legally include not only signs on posts, but also road markings,

traffic signals and other traffic control devices. However, this Manual is limited to signs on

posts (generally and in this Manual called “traffic signs”), road markings and traffic signals.

For each sign, marking and signal the manual describes:

when to use it

what its layout or design should be

what size it should be

where it should be placed

The Manual covers three main classes of traffic control devices, each of which consists of sub

classes according to the figure below.

Road Studs

Traffic Signs

Railway Crossings

Traffic Signals

Pedestrian crossingsTransverse Markings

Longitudinal Markings Intersections

Road Markings

Other Markings

Supplementary Plates

Warning Signs

Regulatory Signs

Guidance Signs

Information Signs

Figure C.1 Overview of the contents of the Traffic Signs Manual




C.2 REFERENCE NUMBERS Each sign is given a reference number. The reference number system has been chosen to

make it possible to give new signs reference numbers corresponding to the appropriate group

of signs. The reference number consists of a letter (or two) and a two digit number and, for

some signs, a third digit.

Example: W01.1

The letter indicates the main group:

W Warning signs

R Regulatory signs

G Guidance signs

I Information signs

S Supplementary plates

M Road markings

TS Traffic signals

The two digit numbers refer to the specific sign. Subgroups of signs have consecutive

numbers. For example:

W 01-15 are signs warning for the changes in the road layout

W 21-34 are signs warning for the roadway and roadside hazards

The third digit, if any, indicates a variation of the main sign. For warning signs, regulatory

signs and road markings 1 generally indicates “Left” and 2 indicates “Right”. For example:

W 01.1 is a warning sign for sharp curves to the left

W 01.2 is a warning sign for sharp curves to the right

M 42.1 is a lane arrow for a left turn lane

M 42.2 is a lane arrow for a right turn lane

For guidance signs 1 refers to the sign for primary roads and 2 refers to signs for secondary

and local roads. For example:

G 05.1 is a lane pre-selection sign on primary roads

G 05.2 is a lane pre-selection sign on secondary and local roads

For some signs, e.g. supplementary plates, the third digit has another meaning.




D. TRAFFIC SIGNS

D.1 GENERAL PURPOSE OF TRAFFIC SIGNS Clear and efficient signing is an essential part of the road system, and a road with poor sign-

ing or with badly maintained signs is not functioning well. Road users depend on signing for

information and guidance, and road authorities depend on signing for traffic control and

regulation, and for road safety.

The key requirements for each traffic sign are that it should:

meet a need

command attention

be legible

convey a simple, clear meaning at a glance

be placed so as to give road users time to respond

command respect.

Signs must only be used where there is a clear need for them. The incorrect or unnecessary

use of a sign annoys drivers, and when this happens frequently drivers lose respect for the

sign, and it becomes ineffective in situations where it is really needed. For the same reason,

avoid using signs which impose a restriction which will be very unpopular and difficult to

enforce. Drivers will stop taking signs seriously when they see others ignoring them without

being caught.

Using standard signs assists in their quick recognition, as does uniformity of shape, colour

and lettering for each type. To obtain the full benefits of standardisation, the signs must be

used in a consistent manner.

It is important that the message be presented in a simple way. The new signs make a great use

of pictorial symbols, as these are much more effective than words, and can be understood by

those who cannot read. Signs with words are used only where there is no alternative.

Signs must have sufficient impact to be noticed by drivers. This has been taken into account

in the design of the signs, but the size and siting of the sign are also relevant. For most signs

there are several permitted sizes, and it is largely the speed of the traffic at the site that deter-

mines which size is appropriate.

The symbols and legends on signs must be easy to read. This has influenced the design of the

symbols, lettering, letter spacing, colours, etc., but size is again of most importance, as drivers

who are travelling fast need to be able to recognise a sign from a long distance away. This

means that the symbols and lettering need to be large enough to enable drivers to recognise

them at the required distance.

Traffic signs must be visible at night. They must be reflectorised so that they show up clearly

in vehicle headlights.

Traffic signs should be constructed and erected so that they will last for many years without

any attention apart from regular cleaning.




D.2 CLASSIFICATION OF TRAFFIC SIGNS The main functions of traffic signs are to warn, regulate, guide and inform. There is a group

of signs for each of these functions, and the signs in each group have a special shape and

colour to help drivers recognise them quickly. Two very important signs, the “Stop” and

“Give Way” signs, have their own unique shapes.

Where there is a need to qualify or expand the message on the main sign the additional

information is contained on a supplementary plate. The five main groups of traffic signs are:

Warning Signs - warning drivers of dangers or difficulties on the road ahead

Regulatory Signs - telling drivers what they must do or must not do

Guidance Signs - helping drivers to find the way to their destination

Information Signs - helping drivers find services and places of interest

Supplementary Plates - giving supplementary information to the main sign

Each of these groups can be divided into sub groups according to the chart below.

Advance direction

signs

Travelling directions

Temporary warning

signsReserved routes

InformationGuidance

Guidance signs Information signs

Services facilities and

places of interest

Tourist attractions

Road and traffic

End of restriction

Vehicle categories

Direction signs

Regulation

Mandatory signs

Vehicle movements

and useConfirmatory signs

Place identification

signs

Distances and

directions

Priority and give way

Temporary guidance

signs

Supplementary plates

Text information

Warning

Vehicle categories

Vehicle dimensions

and weightHazard marker signs

Standard warning

signs

Warning signs Prohibitory signs

Figure D.1 Overview of traffic signs




D.3 TRAFFIC SIGN SIZES Most warning signs are triangular and most regulatory signs are circular. The sign sizes to be

used for different speed classes are shown in the table below.

Traffic speed Size of triangular signs Size of circular signs

Side length (mm) Diameter (mm)

≤ 50 km/h 720 600

>50 km/h and ≤ 80 km/h 900 750

> 80 km/h 1100 900

Table D.1 Basic traffic sign sizes

D.4 SITING AND MOUNTING OF TRAFFIC SIGNS

D.4.1 Introduction

The way signs are arranged and positioned is very important for their effectiveness. There are

four things to consider:

whether the sign will be mounted with other signs, or with a backing board

its position in relation to the edge of the carriageway

the height of the sign plate and its angle to the road

where it is to be sited in relation to the intersection, hazard, etc., to which it refers.

General advice on sign mounting and positioning is given below. Where there are special

requirements for a specific sign, these are referred to on the sign page in Appendix 3 (Volume

2). The recommendations should be used as a guide, because the precise positioning can only

be determined on site. There are often limitations on where signs can be placed, especially in

urban areas. Always check that:

the signs are clearly visible from the appropriate distance

there is no confusion about which road the sign refers to

the signs do not obstruct the view of drivers

the signs are not placed where they could be struck by vehicles.

If necessary, alter the siting or mounting to overcome the problem.




D.4.2 Siting

Signs should generally be sited on the left-hand side of the road. However, at sharp left-hand

bends it may be better to put the sign on the right-hand side of the road where it will be more

noticeable. On dual carriageway roads warning and regulatory signs are normally installed in

pairs – one on the left-hand side and another on the median. Speed limit signs are always put

on both sides of the road, for maximum impact.

Most warning signs, and some guidance signs, have to be sited in advance of the hazard or

intersection to which they relate. The distance depends on the traffic speed at the site.

Guidance on siting distances is given in the section of the Manual on each sign group. It is

important to be consistent, so that drivers will become familiar with the rate at which they

have to slow down. When signs have to be sited far away from their standard position, a

supplementary plate may be used to give the distance to the intersection or hazard. It is better

to increase the distance between a sign and the intersection or hazard to which it relates, rather

than decrease it.

Regulatory signs are normally sited at or near the point where the instruction applies. Care

must be taken to ensure that there is no confusion about which road they refer to.

Signs are designed to be read from a specific distance, so the sign must be sited where it can

be seen from this distance. The visibility distances are set out in the table below.

Traffic speed

(km/h)

Visibility distance to the sign

(m)

Up to and including 50 km/h 50

Over 50 km/h and up to and including 80 km/h 150

Over 80 km/h 200

Table D.2 Visibility distance requirements

Where two traffic signs are needed, such as on the approach to a sharp bend leading onto a

narrow bridge, the sign for the nearest hazard should be seen first. The second sign should be

placed at least 0.6v beyond the first sign (where v is the traffic speed in km/h) to prevent it

being obscured by the first sign. The minimum separation should be 30 metres. Where this is

difficult to achieve consider mounting the two signs on the same pole.

D.4.3 Mounting

D.4.3.1 Mounting Height

Signs should normally be mounted so that the lower edge of the primary sign plate is 1.8

metres above the highest point of the carriageway. Mounting the sign at this height helps to

discourage vandalism and theft. Where the sign is mounted over or alongside a footway (or

footpath) the lowest edge should be 2.1 metres above footway level. Some signs are used at

non-standard mounting heights and where this is the case it will be specified on the sign page

in Appendix 3 (Volume 2). Signs should never be mounted less than 1 metre above

carriageway level, as below this level they will get too dirty from rain splash and vehicle

spray.




Mounting height for overhead signs and signals on gantries and mast arms should be 5.2

metres, measured from the bottom edge of the sign to the carriageway. This allows for the

possibility that the carriageway level might rise when the road is resurfaced. Road authorities

should ensure that there is always 5.0 metres clearance between overhead structures and the

carriageway.

Minimum (mm) Desirable (mm) Maximum (mm)

A 600 1000 2500

B 1000 1500 2500

C 300 600

D 1000 1800 2500

E 2100 2100 2500

F 5000 5200

G 750

H 5000

Figure D.2 Heights and clearances

D.4.3.2 Clearance from the Edge of the Road

Signs must be set back from the road to reduce the risk of them being hit by passing vehicles.

On unkerbed roads the nearest edge of a sign should be at least 600mm clear of the road

shoulder and should not be less than 1 metre from the edge of the traffic lane, see Figure D.2.

On kerbed roads the edge of the sign should be not less than 300mm from the kerb face. Signs

on traffic islands are especially vulnerable to being hit, and a small-size sign may have to be

used to achieve the necessary clearance. Avoid siting signs at places where vehicles park on

the shoulder.

B

DG

A

D

H

E

C

D

C

C A

F

Footway

Kerb

Kerb

No shoulder Shoulder




D.4.3.3 Multiple Signs

Two signs can be mounted on the same sign pole. When two warning signs are mounted

together the sign at the top should refer to the nearest of the two hazards. When two rectan-

gular signs are being mounted on the same poles it looks neater if the two signs are made the

same width.

D.4.3.4 Supplementary Plates

These plates are mounted beneath the primary sign to which they refer and there is normally a

gap of 75mm between them. Supplementary plates are more easily vandalised than larger

signs. One solution, though more costly, is to combine the supplementary plate with the

primary sign on the same sign plate or backing board.

Figure D.3 Alternative methods of mounting supplementary plates

D.4.3.5 Backing Boards

Signs can sometimes be difficult to see against the background. Where this is a problem the

sign can be mounted on grey or yellow backing boards. Yellow backing boards can be very

effective, especially if the yellow is fluorescent, but they should only be used for important

signs in difficult-to-see situations. If yellow backing boards are very widely used people will

stop noticing them. An alternative way of making a sign more noticeable is to increase its

size.

0.05H

H

0.05H

0.1 Dia.

Diameter

0.1 Dia.

0.05H 0.1 Dia.

Figure D.4 Signs on a yellow backing board

Traffic signal heads should be fitted with black backing boards to make them more visible.




D.4.3.6 Angle of the Sign Plate

Sign plates are normally mounted so that they face the driver. The plate should be angled

slightly away from the road to avoid mirror reflection when illuminated by vehicle headlights.

To obtain a 95° the sign should be angled 90mm per metre sign width. Signs on curves should

be at right angles to the driver‟s line of sight, measured from when the driver is about 100

metres from the sign.

Figure D.5 Angle of the sign plate

Signs should normally be installed vertically, but on steep hills signs can be tilted forward (or

back) from the vertical to improve the viewing angle. Overhead signs are usually tilted back

about 30 to reduce glare from the vehicle headlights.

95o




D.5 WARNING SIGNS

D.5.1 Purpose and Use

Warning signs are used to alert drivers to danger or potential danger ahead. They indicate a

need for extra caution by road users and may require a reduction in speed or other manoeuvre.

This section contains an overview of all warning signs. Advice on when to use each sign is

given in Appendix 3 (Volume 2).

Adequate warning signs can greatly assist road safety. To be most effective however, they

should be used sparingly. Their frequent use to warn of conditions which are otherwise

readily apparent tends to detract from their effectiveness.

Do not use warning signs in situations where the problem is obvious, or is so minor that no

extra care is necessary. If they are over-used, drivers will lose respect for them. This is

particularly true when specifying signs for urban roads. Side road intersections for example

are not usually a danger when traffic speeds are low.

Most warning signs are triangular in shape with a red border encompassing a black symbol on

a white background. The black symbol represents the hazard. Sometimes additional informa-

tion is put on a supplementary plate below the main sign.

D.5.2 Siting and Sizes

Drivers must be able to see the sign in time to read the message. The distance varies with the

traffic speed – refer to Table D.2. Warning signs are placed at the left-hand side of the road.

It takes time for a driver to act on the message given by a sign and slow the vehicle down to a

safe speed. Therefore signs must be sited sufficiently far ahead of the hazard to allow for this.

Signs must also be large enough to be read clearly by drivers travelling at above average

speeds. Table D.3 gives the siting distances and sizes of standard warning signs for different

traffic speeds. If it is necessary to site the sign away from the standard position, the distance

to the hazard should be indicated on a supplementary plate.

Traffic speed

Normal distance of sign from hazard

(m)

Sign size

Side length

(mm)

Up to and including 50 km/h 50 720

Over 50 km/h and up to and including 80 km/h 100 900

Over 80 km/h 150 1100

Table D.3 Siting and sizes of standard warning signs

Some warning signs, hazard marker signs and temporary warning signs are sized and sited

differently. The necessary information is given in Appendix 3 (Volume 2).




D.5.3 Schedule of Warning Signs

The schedule contains the name, reference number and a small picture of each sign. The

detailed design and use of each sign is described in Appendix 3 (Volume 2).

D.5.3.1 Standard Warning Signs

Road Layout

W01 Sharp curve W02 Hairpin curve

Temporary

Temporary

W03 Combined curves W04 Crossroad

Temporary

Temporary

W05 Side road W06 T-intersection

Temporary

Temporary

W07 Y-intersection W08 Staggered intersection

Temporary

Temporary

W09 Roundabout W10 Traffic signal

Temporary

Temporary

W11 Road narrows on both sides W12 Road narrows one side

Temporary

Temporary

W13 Dual carriageway ends W14 Dual carriageway ahead

Temporary

Temporary

W15 Two-way traffic

Temporary




Roadway and roadside hazards

W21 Other danger W22 Height restriction

Temporary

Temporary

W23 Uneven road W24 Hump

Temporary

Temporary

W25 Drift W26 Narrow bridge

Temporary

Temporary

W27 Loose gravel W28 Slippery road

Temporary

Temporary

W29 Falling rocks W30 Steep descent

Temporary

Temporary

W31 Steep ascent W32 Quay or river bank

Temporary

Temporary

W33 Low flying aircraft W34 Crosswinds

Temporary

Temporary

Other vehicles, road users and animals

W41 Railway crossing with gate or barrier W42 Railway crossing without gate or barrier

Temporary

Temporary

W43 Pedestrian crossing W44 Pedestrians in the road

Temporary

Temporary




W45 Children in the road W46 Cyclists in the road

Temporary

Temporary

W47 Agricultural vehicles W48 Domestic animals

Temporary

Temporary

W49 Wild animals

Temporary

D.5.3.2 Hazard Marker Signs

W61 Long chevron W62 Short chevron

No temporary version


W63 T-intersection chevron W64 Roadside hazard plate



W65 Roadway hazard plate W66 Delineators



W67 Railway crossing, one line W68 Railway crossing, more than one line



W69 Distance indicators





D.5.3.3 Temporary Warning Signs

W81 Roadworks W82 Lane closed

Temporary sign only

Temporary sign only

W83 Cross-over to opposing roadway W84 Barricade (no entry)

Temporary sign only

Temporary sign only

W85 Traffic control ahead

Temporary sign only




D.6 REGULATORY SIGNS


Regulatory signs are the means of putting into practical effect the regulation or control of

traffic. For example, they may impose restrictions on speed or on the turning of traffic at an

intersection.

Regulatory signs are either prohibitory or mandatory.

The prohibitory signs give instructions to drivers about what they must not do. Speed limit

signs and signs for parking restrictions are some examples. Most prohibitory signs are circular

with a red border and have a black symbol on a white background.

The mandatory signs give instructions to drivers about what they must do. Most mandatory

signs are circular with a white symbol and border on a blue background.

Regulatory signs must only be used where it is considered essential that traffic be controlled

for safety reasons or for efficient use of the road system. Drivers will take more notice of

them if they can see why they are needed.


Regulatory signs are normally sited at or near the point where the instruction applies. It is

important to make sure that there is no confusion about which road they refer to. Drivers must

be able to see the sign in time to read the message and act on it. The distance varies with the

traffic speed – refer to Table D.2. Regulatory signs are placed at the left-hand side of the road,

but a second sign on the right-hand side may be used where extra emphasis is needed - for

example on dual carriageways. Table D.4 gives the sizes for standard regulatory signs at

different traffic speeds.

Traffic speed Diameter of sign

(mm)

Low speed areas where space is limited 400



Over 80 km/h 900

Table D.4 Sizes of standard regulatory signs

Some priority signs are sized differently. The necessary information is given in Appendix 3

(Volume 2).

D.6.3 Schedule of Regulatory Signs






D.6.3.1 Prohibitory Signs

Restricted vehicle categories

R01 No entry for any vehicle R02 No entry for motor vehicles


Temporary

R03 No entry for motor vehicles except motorcycles

R04 No entry for trucks

Temporary

Temporary

R05 No entry for buses and coaches R06 No entry for motorcycles

Temporary

Temporary

R07 No entry for tractors or slow-moving vehicles

R08 No entry for cycles

Temporary

Temporary

R09 No entry for pedestrians R10 No entry for animal-drawn vehicles

Temporary

Temporary

Restricted vehicle dimensions and weight

R21 Length limit R22 Height limit

Temporary

Temporary

R23 Width limit R24 Gross weight limit

Temporary

Temporary

R25 Axle weight limit

Temporary




Restricted vehicle movements and use

R41 No Left/Right Turn R42 No U Turn

Temporary

Temporary

R43 No overtaking R44 No overtaking by goods vehicles

Temporary

Temporary

R45 No use of horn R46 Compulsory stop

Temporary

Temporary

R47 No Parking R48 No Stopping



R49 Speed limit

Temporary

End of restrictions

R51 End of restriction R52 End of speed limit

Temporary

Temporary

D.6.3.2 Mandatory Signs

Priority and give way

R61 Stop R62 Give Way



R63 Temporary traffic control - STOP R64 Temporary traffic control - GO

Temporary sign only

Temporary sign only




R65 Give way to oncoming vehicles


Travelling directions

R71 Ahead Only R72 Turn Left / Right



R73 Turn Left / Right Ahead R74 Ahead or Turn Left / Right



R75 Pass Left / Right Side Only R76 Pass Either Side



R77 Roundabout


Reserved routes

R81 Route for Buses Only R82 Route for Cycles Only



R83 Route for Pedestrians only





D.7 GUIDANCE SIGNS


Guidance signs give road users information on how to find their way to their destination.

They also help to reduce delay and keep traffic flowing smoothly and safely through

intersections. It is important that the signing is consistent along the route. Once a destination

appears on a guidance sign it must appear on all subsequent guidance signs until that place is

reached.

Guidance signs belong to one of three major groups:

Advance Direction Signs give route information ahead of intersections. There are three

alternative layouts for advance direction signs:

Map-type – that shows a map of the intersection

Stack-type - that lists the destinations alongside direction arrows

Lane pre-selection sign - that indicate the lane to use to get to each destination.

Map-type signs are generally larger than stack-type, and thus more expensive, but they give

drivers a better understanding of how the intersection is laid out. They should always be used

where there is a roundabout or where the intersection layout is in any way complex. Stack-

type signs should only be used at simple intersections, and should not indicate more than three

directions.

Small-sized warning signs and regulatory signs, e.g. height and weight restrictions, may be

incorporated into advance direction signs and direction signs if the information will be

essential in deciding which route to take.

Direction Signs give route information at intersections

Confirmatory Signs confirm the destinations on the route ahead

Place Identification Signs give place names.

D.7.2 Siting

Drivers must be able to see the sign in time to read the message. The distance varies with the

traffic speed – refer to Table D.2.

Advance Direction signs should be sited as shown in Table D.5.

Traffic speed

Distance of sign from intersection

(m)



Over 80 km/h 150

Table D.5 Siting of advance direction signs

Direction signs are placed at the intersection and point along the route shown on the sign.

Confirmatory signs are usually sited 100-150 metres beyond the intersection. Between

intersections, signs should be sited at intervals of no more than 20 kilometres.




Place Identification signs are sited at the place named on the sign. At trading centres and

towns they are sited at the edge of the built-up area.

D.7.3 Sizes and Design Principles

There are no standard sizes for guidance signs. The size of the sign is determined by the

amount of information needed and the size of the lettering to be used on the sign.

The lettering sizes are set out in the table below. Once the lettering size has been chosen, the

design should proceed according to the layout rules set out in Appendix 1 (Volume 2).

Traffic speed x-height

1)

(mm)

Capital letter height

(mm)



Over 80 km/h 200 280

1) x-height = the height of the letter “x” in lower case

Table D.6 Letter sizes for guidance signs

No more than four destinations are permitted on one sign. No more than two destinations are

permitted for any one direction, except on Confirmatory signs. Where two or more

destinations are shown for one direction the nearest destination will be at the top.

Guidance signs may include important destinations that can be reached indirectly by

following one of the roads that is being signed.

Guidance signs are colour coded to help drivers differentiate between primary roads and other

roads. Signs referring to primary roads have white lettering on a green background, and all

others will have black lettering on a white background. Where a sign refers to both primary

roads and other roads it will have white lettering on a green background throughout.

D.7.4 Schedule of Guidance Signs


detailed design of text-based signs like these is covered in Appendix 1 (Volume 2). Appendix

2 shows the layout of Guidance Signs at typical intersections. Appendix 3 gives detailed

advice on the design and use of each sign.




Advance direction signs

G01.1 Map-type advance direction sign -roundabout - Primary roads.

G01.2 Map-type advance direction sign -roundabout – Other roads.



G02.1 Map-type advance direction sign -crossroad - Primary roads.

G02.2 Map-type advance direction sign -crossroad – Other roads.



G03.1 Map-type advance direction sign –T-intersection - Primary roads.

G03.2 Map-type advance direction sign –T-intersection – Other roads.



G04.1 Stack-type advance direction sign - Primary roads.

G04.2 Stack-type advance direction sign - Other roads.



G05.1 Lane pre-selection sign - Primary roads.

G05.2 Lane pre-selection sign - Other roads.



Direction signs

G11.1 Direction sign - Primary roads G11.2 Direction sign - Other roads






Confirmatory signs

G21.1 Confirmatory sign - Primary roads G21.2 Confirmatory sign - Other roads



Place identification signs

G22.1 Place identification sign, entry G22.2 Place identification sign, exit



Temporary guidance signs

G31 Diversion ahead G32 Diverted traffic

Temporary sign only

Temporary sign only




D.8 INFORMATION SIGNS


Information signs serve one of several purposes:

To mark special facilities or restrictions

To give information about services and facilities ahead, such as parking places, lay-

bys, picnic areas, telephones, etc.

Information signs for service facilities may have an additional panel showing direction (by

means of an arrow) or distance. Such panels shall have a blue background, white border and

white arrow or text.


The siting and sizes are described individually for each sign in Appendix 3 (Volume 2).

D.8.3 Schedule of Information Signs



Road and traffic

I01 Pedestrian crossing I02 Hump



I03 No through road I04 Parking



I05 Bus stop I06 Priority over oncoming vehicles



I07 One Way Road I08 Police control



I09 Start of extra lane I10 End of extra lane






Service facilities and places of interest

I21 Hospital I22 First aid



I23 Telephone I24 Information



I25 Filling station I26 Workshop

2 km



I27 Refreshments I28 Restaurant



I29 Hotel I30 Rest area



I31 Camp site I32 Airport



Tourist attractions

I51 Tourist attraction Example Tourist attraction – Woodland






D.9 SUPPLEMENTARY PLATES

D.9.1 Purpose and Use of Supplementary Plates

Supplementary plates give additional information or clarify the message given by the main

signs. They are mostly used with regulatory or warning signs, and never used on their own.

Supplementary plates are normally mounted below the primary sign leaving a gap of 75mm

between them. However, they can also be combined on a grey backing board (see Figure

D.3).

There are three main groups of supplementary plates:

The first group shows distances and directions to e.g. a hazard or a regulation

The second group shows which vehicle category the message on the main sign applies to

The third group gives additional text information to the message on the main sign.

D.9.2 Sizes and Design Principles

D.9.2.1 Text-based Supplementary Plates

Text-based supplementary plates are designed according to the same principles as guidance

signs. The text shall be in lower case with initial capitals. The normal lettering sizes are set

out in the table below.

Traffic speed x-height (mm)

1)

Capital letter height (mm)



Over 80 km/h 90 126

1) x-height = the height of the letter “x” in lower case

Table D.7 Lettering size on text-based supplementary plates

The letter heights prescribed in Table D7 are for signs that need to be read from a moving

vehicle. Smaller sizes may be used on signs that are read from a stationary position (such as

those giving details of parking restrictions) but the x-height should not be less than 20mm.

The size of the supplementary plate may be adjusted to improve the appearance of the sign

assembly. Avoid having supplementary plates which are wider than the main sign.




D.9.3 Schedule of Supplementary Plates



Distances and direction

S01 Distance to hazard or regulation S02 Extension of hazard or regulation

Temporary

Temporary

S03 Direction in which message applies

Temporary

Vehicle categories

S11 Vehicle category for which message applies – bus

S12 Vehicle category for which message applies – truck

Temporary

Temporary

S13 Vehicle category for which message applies – car

S14 Vehicle category for which message applies – motorcycle

Temporary

Temporary

Text information

S21.1 Variable text message – one line S21.2 Variable text message – two lines

Temporary

Temporary

S21.3 Variable text message – three lines

Temporary




D.10 SIGN MATERIALS AND MANUFACTURE

D.10.1 Sign Standards

Section 5400 of the Ministry of Works, Housing and Communication‟s General

Specifications for Road and Bridge Works (under preparation) sets out detailed standards for

the manufacture and installation of traffic signs alongside and over the carriageway. Strict

adherence to these standards will ensure that the signs are of good quality and will have an

acceptable working life. This section of the Traffic Signs Manual contains general advice on

sign materials and manufacture, but in all cases the General Specifications take precedence.

The components of a traffic sign are:

sign face

sign plate

sign support frame

sign post

D.10.2 Sign Face Materials

It is recommended that all traffic signs, permanent and temporary, be fully reflectorised by

making the sign face from retroreflective sheeting. This is a special type of reflective material

that reflects light back to the light source, which in this case is the vehicle headlight. For

simplicity the sheeting will be referred to hereafter as reflective sheeting. All parts of the sign

face except those coloured black must be made of reflective sheeting, so that the sign looks

the same in both day and night.

There are various grades of reflective sheeting available, each providing different levels of

retroreflectivity when viewed under standard conditions. There are big differences in price.

The General Specifications require that High Intensity Grade be used, and this is defined by

reference to standards used in the United States. The contractor must submit sign specifica-

tions, test certificates, and warranties, as required in the General Specifications. The warranty

must say that, if the retroreflective performance of the sign falls below a specified minimum

during the warranty period, the sheeting manufacturer will replace the sign or restore it to its

original performance. This is the best way of ensuring that the signs will be of proper quality.

Coloured areas should preferably be made from sheeting of the appropriate colour or by

applying coloured overlay film onto white sheeting. The use of inks or paints is not

recommended, as this gives inferior performance. Symbols or letters coloured black shall

preferably be made from black non-reflective overlay film. Film and sheeting shall come from

the same manufacturer and be applied in accordance with their instructions.

It is important to use standard colours on traffic signs, though the small variations that occur

between sheeting from different manufacturers are permissible. The colours of the sheeting

shall conform to the colour specification limits (chromaticity co-ordinates) set out in ASTM

D4956.

D.10.3 Sign Plate

Aluminium alloy sheet is the preferred material, because of its resistance to corrosion.

However, it is expensive. Cheaper alternatives are galvanised steel, plastic-coated steel, or




steel treated with primer. The cleaning and preparation of steel plates needs to be of a very

high standard, but even then there will always be a risk that the plate will corrode around the

bolt holes or places where the coating has been damaged. With all materials, proper cleaning

and degreasing is essential to ensure good adhesion of the sheeting. The back of the sign plate

shall be painted grey, and the sign manufacturer‟s name and the date of manufacture shall be

permanently marked on it.

D.10.4 Sign Support Frame and Fastenings

All sign plates, with the exception of very small ones, need to be stiffened so as to prevent

them from being deformed by wind pressure, minor collisions, or attack by vandals. This is

normally done by riveting the sign plate to a back support frame made of angle iron or

aluminium sections. It is essential that all frames, brackets, clips, rivets, nuts, bolts and

washers be corrosion-proofed if not made of aluminium or stainless steel. The frames and

brackets shall then be painted grey. The method of fixing to the post shall be as shown on the

scheme drawings or be as approved by the engineer in charge of the scheme.

D.10.5 Sign Post

Sign posts will normally be made of galvanised steel tube set in concrete foundations.

D.10.6 Checklist of Sign Supply Requirements

It is recommended that contractors be asked to provide the following information and items

before manufacturing and supplying signs:

name of sign manufacturer and sheeting manufacturer

retroreflective performance of the sheeting, as determined by a reputable laboratory

letter of warranty, endorsed by the sheeting manufacturer, specifying the minimum

retroreflective performance at the end of the warranty period (the warranty should be

specific to the contract)

a sample of the reflective sheeting for each colour and grade to be used

a sample sign

details of the sign plate stiffening and fastenings (unless included in the drawings)

a written declaration that the signs to be supplied will meet all the requirements of the

specifications.




D.11 MAINTENANCE OF TRAFFIC SIGNS

D.11.1 General

A high standard of maintenance of signs, signals and road markings is essential if they are to

fulfil their purpose. It is a waste of money to provide signs and then to allow them to lose

their effectiveness by subsequent deterioration. Signs that use High Intensity Grade sheeting

and are well-made should perform acceptably for at least 7 years.

All signs and markings should be inspected at regular intervals both by day and night. They

should be renewed as necessary. Signs become less effective not only when characters or

colouring deteriorate, but also when dirty or damaged, or displaced as a result of accidents or

vandalism. Damaged or dirty signs lessen road users‟ respect for the signs. Regular cleaning

of all signs is essential.

It is not possible to recommend suitable renewal intervals for markings as these will depend

very much on the type of line, the material comprising the marking and on the road traffic

conditions. Nevertheless a carriageway marking maintenance programme should be adopted

to keep the road markings under constant review to ensure that the markings are maintained to

a high state of effectiveness at all times, particularly on heavily trafficked roads.

Markings should be renewed or re-laid when they have been removed or damaged by road-

works. New surfaces should preferably be allowed to settle and harden up for a few weeks

before applying markings. Arrangements should be made to protect road studs during surface

dressing operations.

D.11.2 Maintenance Regime

D.11.2.1 Record Keeping and Inspection

The key to good maintenance is proper record-keeping and regular inspection. An inventory

of markings, signs, and other road furniture is helpful. In addition to a description of the item

and its location, it can usefully include installation and inspection dates, and repair details.

The inventory number should be painted on the back of the sign plate.

Inspections should be made at least twice a year, preferably after routine cleaning has been

done. The things to look for are:

signs that are missing or in the wrong location

signs that are pointing the wrong way or are tilting

signs that are hidden by trees or bushes

posts that are loose in their foundations

sign plates that are loose

corrosion of sign plates and posts

accident or other damage

flaking or faded sign faces and painted surfaces

poorly reflecting sign faces (best checked at night)

worn or faded road markings.

Keep good records of the faults that are found and the action taken.




D.11.2.2 Cleaning

Signs should be cleaned at least twice a year, and priority should be given to low-mounted

signs. Cut back any long grass, bushes or tree branches which hide the sign face. Use water

and a mild detergent to wash the sign and take care not to scratch the surface. Rinse the sign

in clean water to remove all traces of detergent. Road tar can be cleaned off with petrol or

white spirit, but be careful not to dissolve the paint, and rinse well afterwards.

D.11.2.3 Repairs

Minor repairs and repainting can be done on-site. Repainting should only be done in dry

weather and after proper preparation of the surface. Do not apply paint to reflective sheeting,

because this will make it non-reflective. Similarly, do not use ordinary road paint on reflec-

torised road markings.

D.11.2.4 Storage and Transport of Signs

Signs are expensive. Always store them where they cannot be damaged. Stack them

vertically, if possible, and put sheets of cardboard or thick paper between them to prevent the

sign faces from getting scratched. Take care when loading signs on and off trucks, and do not

allow them to bounce around while being transported.




E. ROAD MARKINGS

E.1 PURPOSE AND CLASSIFICATION OF ROAD MARKINGS The purpose of road markings is to control, warn, or guide road users. They may be used to

supplement other traffic signs or they may be used alone. Their major advantage is that they

can give a continuing message to the driver. Thus they can be used to guide drivers in the

correct positioning of their vehicles so that the traffic flows smoothly and safely. Some help

clarify or emphasise the meaning of other signs. Improved road marking is often the most

cost-effective solution to traffic and accident problems.

The markings have the limitation that they get covered up by dirt, and they wear away quite

quickly on heavily-trafficked roads. Nevertheless, they serve a very important function in

conveying to drivers information and requirements which might not otherwise be possible by

post-mounted signs.

Where traffic congestion occurs, extensive use of road markings is essential to ensure that full

use is made of the available road space. In particular, widespread use of lane markings is

desirable; by enhancing lane discipline they add to the safety of traffic, besides improving

traffic flows. And at intersections road markings can be very useful in showing drivers where

to stop and look.

It is strongly recommended that road markings be considered in detail at the design stage of

new or improved intersections.

Road markings are classified as follows:

Longitudinal markings – dividing lines, lane lines and edge lines

Transverse markings – stop line, give way line and pedestrian crossings

Other markings – arrows, restricted areas, text and symbols




E.2 LONGITUDINAL MARKINGS Dividing (centre) lines

M01 Continuous dividing line

100 mm wide yellow line

M02 Double continuous dividing line

Two 100 mm wide yellow lines with 130 mm separation

M03 Broken dividing line

100 mm wide yellow line. Urban areas: 3 m mark with 6 m gap. Rural areas: 4 m mark with 8 m gap

M04 Combination of continuous and broken dividing line

M01 and M03 with 130 mm separation

M05 Zig-Zag dividing line

100 mm wide yellow line. Urban areas: 2 m mark with 150 mm gap

Lane lines

M11 Continuous lane line

100 mm wide white line

M12 Broken lane line

100 mm wide white line. Urban areas: 3 m mark with 6 m gap. Rural areas: 4 m mark with 8 m gap




Edge lines

M21 Standard edge line

100 mm wide white line

M22 Continuity line

100 mm / 200 mm wide white line. Urban areas and rural areas: 1 m mark with 1 m gap

M23 No parking line

100 mm wide yellow line




E.3 TRANSVERSE MARKINGS M31 Stop line M32 Give way line

M33 Uncontrolled pedestrian crossing M34 Signal-controlled pedestrian crossing

M35 Hump

E.4 OTHER MARKINGS Arrows

M41 Lane arrow – ahead only

M42.1 Lane arrow – left turn only M42.2 Lane arrow – right turn only

M43.1 Lane arrow – ahead or left turn M43.2 Lane arrow – ahead or right turn

M44.1 Diverge arrow – ahead of left turn lane M44.2 Diverge arrow – ahead of right turn lane

M45.1 Deflecting arrow - left M45.2 Deflecting arrow - right




Restricted areas

M51 Chevron marking – merging M52 Chevron marking – diverging

Directionof travel

Directionof travel

M53 Traffic island marking – between opposing directions

Text and symbols

M61 Give way marking M62 Text marking - STOP

M63 Speed limit marking

Parking

M71 Parking bay




E.5 MARKING MATERIALS

E.5.1 Road Marking Standards

Section 5500 of the General Specifications for Road and Bridge Works (under preparation)

sets out detailed standards for the manufacture and application of road markings. Strict

adherence to these standards will help ensure that the marking performs well for an acceptable

period. This section of the Traffic Signs Manual contains general advice on road marking

materials and application, but in all cases the General Specifications take precedence.

Road marking requires special equipment and skills, and is best done by a contractor who

specialises in this activity. The quality of the road marking will be very dependent on the skill

and experience of the contractor‟s staff.

It is important with all road marking work to give careful attention to surface preparation,

setting out, and testing of the equipment. Templates should be used for arrows, symbols,

words and other complicated shapes.

E.5.2 Road Paint

The paint used for road markings should be manufactured specially for this purpose. It should

be quick-drying, durable and have good skid resistance. The paint is normally applied by a

spray machine, but some markings are easier to do with a brush. When ordering road paint the

proposed method of application must be specified to ensure that the correct type of paint is

supplied.

E.5.3 Thermoplastic

Hot-applied thermoplastic is taking over from road paint as the preferred marking material.

The initial cost is higher than for paint, but it is far more durable, so it will usually be the

more cost-effective option. It can be sprayed or screeded onto the road surface. Transverse

lines, arrows, symbols, and words are most easily created by screeding. A high standard of

materials, equipment and workmanship is needed to produce good-quality markings.

E.5.4 Reflectorised Markings

Road markings should be reflectorised by the addition of reflecting glass beads. It is

important to ensure that the glass beads meet the specifications. With thermoplastic the beads

will normally be mixed into the material and more will be sprayed onto the top of the marking

whilst it is still molten. In the case of paint, the beads will be sprayed onto the paint before it

is dry.




E.6 REFLECTIVE ROAD STUDS

E.6.1 Standards

Section 5500 of the General Specifications for Road and Bridge Works (under preparation)

sets out standards for the manufacture and installation of road studs. Modern road studs are

made of high-strength plastic and incorporate corner cube retroreflectors protected by an

abrasion-resistant glass or plastic lens. They are bonded to the road surface using epoxy resin

or other adhesive.

E.6.2 Purpose and Use of Road Markings

Reflective road studs can be very effective at night, but they are costly, and so are likely to be

used only where clear guidance at night is critical for safety or smooth traffic flow. Road

studs on dividing lines and lane lines must reflect a white light, though the body of the stud

should preferably be the same colour as the line marking. Table E.1 below indicates the

colour and spacing of reflective road studs for each of the main types of longitudinal road

marking. Note that the reflected light from the studs should be seen only by the traffic

approaching on the left-hand side of the road. This means that studs on edge lines and lane

lines should normally be one-sided (uni-directional).

Reflective road studs should not be used on transverse markings, as they could interfere with

stopping ability, and may be hazardous to two-wheeled vehicles.

Type of road marking Colour shown by

stud Spacing of road studs

(m)

Urban Rural

M01 Continuous dividing line White 6 6

M02 M04 Double dividing line White 6 6

M03 Broken dividing line White 18 24

M12 Broken lane line White 18 24

M21 Edge line Red

(Amber on edge lines next to medians)

18 24

M22 Continuity line Green 3 3

Table E.1 Spacing of reflective road studs




F. TRAFFIC SIGNALS

F.1 PURPOSE AND CLASSIFICATION OF TRAFFIC SIGNALS

F.1.1 Purpose and Use

Traffic Signals are used for the control and direction of vehicles and pedestrians at:

Road intersections

Pedestrian crossings

Railway crossings.

A comprehensive guide to the design of signals installations is outside the scope of this

Manual. This section gives a general outline of what the signals practice should be, together

with advice on the siting and mounting of signal heads.

Traffic signals other than rail crossing signals should normally be used only on streets and

roads with a speed limit of 50 km/h or lower. They can, exceptionally, be used on roads with

speed limits between 50 km/h and 70 km/h, provided the visibility is good, warning signs are

used, the right turns are fully protected (controlled by arrow signals) and at least one signal on

each high-speed approach is mounted overhead.

The signals must be visible from at least 70 metres away (or 110 metres if the traffic speed

exceeds 50 km/h). Warning sign W10 “Traffic Signal” must always be used where the

visibility is marginal, but do not install signals where the visibility on any approach is well

below these limits.

F.1.2 Schedule of Traffic Signals

The schedule contains the name, reference number and small pictures of each signal. Standard

design and use of each signal is described in the following sections.

TS01 Traffic signals

TS01.1 Standard signal

TS01.2 Arrow signals

TS02 Pedestrian signals

TS03 Traffic signals at railway crossings




F.2 TRAFFIC SIGNALS

F.2.1 General

The main reasons for installing traffic signals at intersections are to reduce conflicts and avoid

congestion. The signal installation should be designed to achieve safety and efficiency within

the available road space. Traffic signals are also used to control traffic at signal-controlled

pedestrian crossings.

F.2.2 Standard Design

Traffic signals consist of three lights mounted vertically. Red shall be on the top, amber in the

middle and green at the bottom.

Where it is necessary to control different traffic movements independently the plain lights

should be replaced by arrows. The arrows have the same meaning as the plain lights but they

apply only to the traffic proceeding in the direction indicated by the arrow. Arrows for

straight-on traffic should point upwards.

The use of a separate signal head with red, amber and green arrows gives very good control

and the signals are easily understood. A lane must be provided for the sole use of the traffic in

each direction shown by arrows. The lane should be marked with the appropriate lane arrow.

The green arrow gives drivers the right of way to move in that direction, so there should be no

conflicting traffic movements when the signal is lit.

The standard signal lens should have a diameter of 200 mm. At complicated intersections and

for overhead mounting the diameter should be increased to 300 mm.

Signal heads should be fitted with backing boards to make them more conspicuous. These

should be coloured black with a white border – see Figure F.1.

200 mm(300 mm)

Border: 35(50)

600 mm(900) mm)

275 mm(400 mm)

950 mm(1400 mm)

Dimensions of the backing board may vary.

Figure F.1 Standard design of signals




F.2.3 Interpretation

The sequence of the signals will be red, green, amber, and then back to red. The interpretation

of the signal shall be as follows:

Red A red signal means that traffic may not proceed.

Vehicles shall not pass the stop line, or, if there is no stop line, shall

not pass beyond the signal, or, if the signal is placed after the inter-

section, shall not enter the intersection or move onto a pedestrian

crossing at that intersection.

Green A green signal means that traffic may proceed in any direction

unless such movement is prohibited by a regulatory sign.

However, the driver is not authorised to proceed if traffic is so

congested that by entering the intersection they would probably not

have passed it before the signal turns red again.

Amber An amber signal, appearing alone, means a vehicle must stop, unless

it is so close to the stop line or signal that it cannot stop safely.

Table F.1 Interpretation of traffic signals at intersections

F.2.4 Positioning and Mounting

There should be at least two signals visible on each approach to the intersection – a primary

signal and a secondary signal. Where separate signalling of turning movements is used this

advice applies to the approach lane(s) associated with each turning movement. One signal

post can then display information for more than one turning movement.

The primary signal should be located at the left-hand side of the road at a minimum distance

of 1 metre beyond the stop line (refer to Figures 5 and 6 in Appendix 2 (Volume 2)). Where

there are two or more approach lanes a second primary signal should be installed at the right-

hand side on a traffic island (refer to Figure 6 in Appendix 2 (Volume 2). The secondary

signal gives the same information as the primary signal but is sited beyond the primary signal

and preferably within the driver‟s direct line of sight (it can be displaced up to a maximum of

300 from the direct line of sight). The distance between the stop line and the secondary signal

should not exceed 50 metres. At large, complicated intersections, and on high-speed roads, it

is advisable for the secondary signals to be mounted overhead on mast arms.

Make sure that the driver‟s view of the signals is not blocked by trees, lighting columns, bus

shelters, parked vehicles, or other obstructions.




A driver in a hurry at the stop line may start off early if he can see that the signals on the other

approaches are changing to red. This can be dangerous. To avoid this, site the signals where

they cannot be seen from other approaches, or fit long hoods over the signal lights.

If two signal-controlled intersections are close to each other there is a risk that a driver who is

not concentrating will „see through‟ the first set of signals and will act on the information

given by the second set of signals. This can be dangerous if the signals are not linked and are

running on a different sequence. To avoid this problem try and realign the second set of

signals or fit hoods, so they cannot be seen from the previous intersection.

The lights should be mounted in a black housing and should be protected from direct sunlight

by visors. Black backing boards help make the signals more visible against light backgrounds.

Signals for right-turn traffic shall be mounted to the right of signals for straight-on traffic,

and, similarly, those for left-turn traffic should be on the left. The base of the signal housing

should be not less than 2.1 metres above ground level, in order to leave free passage for

pedestrians. Increase this to 2.3 metres where cyclists are present. There should be a

minimum clearance of 5.0 metres between the carriageway and any part of a signal that is

mounted overhead.

F.2.5 Signal Control Methods and Timings

The aim in designing signal installations is to maximise capacity (minimise overall delay)

while maintaining a high degree of safety. It is important to keep as much traffic moving as

practicable at the same time. Detailed advice on signal control is outside the scope of this

Manual but some of the guiding principles are:

Use the lowest practicable number of stages (changes) in the signal cycle (complete

sequence of stages)

The signal cycle should preferably not exceed 120 seconds

Ensure that each approach is capable of carrying the maximum predicted traffic flow

Ensure that the time allocated to each stage is appropriate to the actual traffic flow (a

control system that can automatically vary the duration of the green signal according to

actual traffic flow is highly desirable on both efficiency and safety grounds)

If appropriate, link adjacent sets of signals so that groups of vehicles can pass through the

intersections without stopping

The duration of the amber signal should normally be 3 seconds

The intergreen period (the period between the end of the green signal for one approach

and the start of the green signal for a conflicting approach) must be sufficient to enable

vehicles to clear the intersection safely – it is normally a minimum of 4 seconds but it

should be extended at large intersections or on high-speed approaches – note however

that long intergreen periods are wasteful and may be abused by drivers

It is highly desirable for right-turn movements to be fully controlled (called a protected

right turn) by means of separate signals (green arrow and, if possible, red and amber

arrows)

When green arrow signals are lit drivers should be able to proceed in the direction of the

arrow without having to merge or give way to conflicting traffic streams.




Drivers must not be permitted to turn left when the main signal is on red, unless there is a

green arrow signal that allows them to do so.

F.3 PEDESTRIAN SIGNALS

F.3.1 General

Pedestrian signals are used in combination with traffic signals at pedestrian crossings within

intersections or at separate pedestrian crossings. The signals may be activated automatically

by the intersection signal controller, or by the pedestrian pushing a button to indicate to the

controller his wish to cross.


The signals shall be arranged vertically with the red signal at the top and the green at the

bottom. The lights can be either a red/green man on black background or a white man on

red/green background

The signal lens should have a diameter of 200 mm. At complicated intersections and at

intersections with many pedestrians the diameter can be increased to 300 mm.

200 (300)

Figure F.2 Alternative designs of pedestrian signals

F.3.3 Interpretation

The signal sequence for pedestrians is red, green and flashing green. The interpretation of the

signal shall be as follows:

Red Standing Man Green Walking Man Flashing Green Man Do not cross the road Cross the road with care The signal is about to turn to

Red. Do not start to cross the

road.

Table F.2 Interpretation of pedestrian signals




It is desirable for pedestrian signals to be fitted with an audible signal that sounds when the

green signal is lit. This is to help blind and partially-sighted pedestrians.


A pedestrian signal is normally mounted on the same post as the traffic signal. The signals

must face across the road so that the signal can be clearly seen by pedestrians. A typical

installation is illustrated in Figure 8 in Appendix 2 (Volume 2).

Minimum vertical clearances from the carriageway shall not be less than 2.1 m and not more

than 2.6 m.

F.4 TRAFFIC SIGNALS AT RAILWAY CROSSINGS

F.4.1 General

This signal is used to control vehicle traffic at railway level crossings. It is recommended that

this signal, together with gates or barriers, be used at all rail crossings. The diameter of the

signal lamps must be at least 200 mm, but 300 mm diameter lamps are preferred. The flashing

red lights may be supplemented by a sound signal. A stop line must be marked on the road to

indicate to drivers where to stop when the red lights are flashing.


Traffic signals at railway crossings consist of two red flashing lights mounted horizontally.

The lights must flash alternately, i.e. when one red light is on, the other must be off.

A signal which flashes white when the railway crossing is open to traffic may be added. This

also indicates to drivers that the light signal is working.

200 min

Figure F.3 Standard design of traffic signals at railway crossings


The signal will be positioned within 5 - 10 metres of the nearest rail line and where it can

easily be seen by drivers halted at the stop line. It can be at the left hand side of the road, but

it may be more visible if it is mounted above the carriageway. Where it is necessary to make

the signal more prominent (such as on a left-hand bend) a second signal may be positioned on

the right hand side of the road.

Traffic Signs Manual Vol.1 FINAL

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Traffic Signs Manual Vol 1