TOWARDS SAFER ROADS IN DEVELOPING COUNTRIES

A Guide for Planners and Engineers

Transport And Road Research Laboratory

Overseas Development Administration

1991 rok, 219 stron, 30x22 cm

stan oceniam na dobry, ślad od zamoczenia na kilkunastu ostatnich stronach – strony z indeksem (maksymalnie 10x6 cm), tekst kompletny, nierozmyty,

fotografia przedstawia oferowany przedmiot

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tekst w języku angielskim

setki ilustracji i rysunków

Acknowledgements ..............................................................................i

Abbreviations and Acronyms ................................................................ U

PREFACE..............................................................................................ill

1. Road safety problems in developing countries ..........................2

1.1 Scale and nature of the problem in developing countries ................ 2

1.2 Road safety & highway design practices in developing countries .... 4

1.3 Lessons to be learned from more industrialised countries .............. 5

2. Institutional Framework............................................................ 6

2.1 Inter-relationships between land-use, transport and road safety .... 6

2.2 Interdependence between enforcement, environment and education 7

2.3 Institutional arrangements.............................................................. 8

2.4 Areas of influence for engineers and planners ................................ 9

2.5 Opportunities for intervention to improve road safety...................... 10

2.6 Safety conscious planning, design fij; operation of road networks .... 11

3. Planning road networks ............................................................14

3.1 Introduction .................................................................................... 14

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3.2 Land-use planning and zoning ........................................................ 16

3.3 Road hierarchy and network design ......................»........................ 18

3.4 Route planning through communities ............................................ 22

3.5 Roads in the hierarchy .................................................................... 24

3.5.1 Primary distributors........................................................................ 24

3.5.2 District distributors ........................................................................ 26

3.5.3 Local distributors............................................................................ 28

3.5.4 Access roads .................................................................................. 30

3.5.5 Pedestrianised areas/routes .......................................................... 32

3.6 Traffic planning for different land-uses .......................................... 34

3.6.1 Residential...................................................................................... 34

3.6.2 Industrial........................................................................................ 36

3.6.3 Commercial/retail .......................................................................... 38

3.6.4 Recreational/tourism...................................................................... 40

3.7 Development control/encroachment .............................................. 42

3.8 Public transport .............................................................................. 44

4. Designing for safety .............................................................. 46

4.1 Link Design .................................................................................... 46

4.1.1 Introduction .................................................................................... 46

4.1.2 Design parameters and speed ........................................................ 48

4.1.3 Sight distance/visibility .................................................................. 50

4.1.4 Horizontal curvature ...................................................................... 52

4.1.5 Transition curves, superelevation and pavement widening.............. 54

4.1.6 Vertical curves ............................................................................... 56

4.1.7 Combination of horizontal/vertical curves ...................................... 58

4.1.8 Gradients and criteria for climbing lanes ........................................ 60

4.1.9 Cross sections ................................................................................ 62

4.1.10 Drainage.......................................................................................... 64

4.1.11 Safety fences and barriers ............................................................. 66

4.1.12 Delineation...................................................................................... 68

4.1.13 Roadside obstacles, street furniture and trees ................................ 70

4.1.14 Median barriers ............................................................................. 72

4.1.15 Lighting ......................................................................................... 74

4.1.16 Laybys, bus stops and service roads .............................................. 76

4.1.17 Urban footways .............................................................................. 78

4.1.18 Rural footpaths and footways .......................................................... 80

4.1.19 Pedestrian/cyclist facilities on bridges ............................................ 82

4.1.20 Facilities for cyclists and slow-moving vehicles................................ 84

4.2 Intersection design ..........................y.............................................. 86

4.2.1 Selection of intersection type ..........T.............................................. 86

4.2.2 Priority intersections ...................................................................... 88

4.2.3 Roundabouts ................;..................... “........................................... 90

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4.2.4 Signal controlled intersections ............'................................,........... 92

4.2.5 Visibility........................................................................................ 94

4.2.6 Warning signs and markings .......................................................... 96

4.2.7 Channelisation ................................................................................ 98

4.2.8 Acceleration/deceleration lanes ...................................................... 100

4.2.9 Pedestrian crossing facilities............................................................ 102

4.2.10 Provision for cyclists/slow-moving vehicles .................................... 104

5. Operating the road network for safety ...................................... 108

5.1 Introduction .................................................................................. 108

5.2 Highway authorities and safety ...................................................... 110

5.3 Road maintenance and safety.......................................................... 112

5.4 Surface treatment and texture ........................................................ 114

5.5 Traffic management ........................................................................ 116

5.6 Access control ................................................................................ 118

5.7 Road signs ................................................................................... 120

5.8 Road markings ................................................................................ 122

5.9 Enforcement of traffic laws .............................................................. 124

5.10 Speed limits .................................................................................... 126

5.11 Parking .......................................................................................... 128

5.12 Heavy Goods Vehicles (HGVs).......................................................... 130

5.13 Providing for public transport.......................................................... 132

Countermeasures at hazardous locations .................................. 134

6.1 Introduction.................................................................................... 134

6.2 Accident data ................................................................................ 135

6.3 Identifying accident blackspots ...................................................... 136

6.4 Accident analysis ............................................................................ 138

6.5 Monitoring and evaluation .............................................................. 140

6.6 Development of countermeasures .................................................. 141

6.7 Problems and remedies .................................................................. 143

6.8 Examples of typical countermeasures to improve road safety.......... 144

6.8.1 Intersection layout; channelisation.................................................. 146

6.8.2 Intersection layout: roundabouts .................................................... 148

6.8-3 Intersection conspicuity .................................................................. 150

6.8.4 Driver expectancy .......................................................................... 152

6.8.5 Overtaking zones ............................................................................ 154

6.8.6 Road markings................................................................................ 156

6.8.7 Lane dividers/Median barriers........................................................ 158

6.8.8 Delineators...................................................................................... 160

6.8.9 Speed reduction devices.................................................................. 162

6.8.10 Limiting access/Street closures ...................................................... 164

6.8.11 Banning turns and crossing movements ........................................ 166

6.9 Countermeasures for pedestrians .................................................. 168

6.9.1 Introduction.................................................................................... 168

6.9.2 Pedestrian crossings ...................................................................... 170

6.9.3 Pedestrian refuges .................. .1^s...................................................... 172

6.9.4 Pedestrian barriers/fences.............................................................. 174

6.9.5 Pedestrian footbridges/underpasses .............................................. 176

7. Road Safety Checklists .................................................... 180

7.1 Formal road safety checking of proposed schemes .......................... 180

7.2 Checklist A: Land-use/Physical plans ............................................ 182

7.3 Checklist B: Network planning ........................................................ 184

7.4 Checklist C: Highway design .........................y................................ 186

7.5 Checklist D; Countermeasures related activity................................ 189

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Appendix A- References .......................................................................... 192

Appendix B - Checklist for site visits to hazardous locations.................... 195

Appendix C - Further details ofTRRL Microcomputer

Accident Analysis Package.................................................. 203

INDEX ................................................................................................206

Tear-out questionnaire ................................................................................ 216

The document has been written as a number of free-standing

sections which have been internally cross-referenced. It also has a

comprehensive index. Those interested in a particular topic, e.g. road

hierarchy, can refer to that particular section and can find all the key

elements and internal and external references which need to be

considered when examining that particular issue (internal references

direct the reader to other relevant sections within this document and

external references direct the reader to documents listed in Appendix A).

Those interested in topics which do not merit a whole free-standing

section can use the index to locate relevant sections of text. In this way

the reader can readily find specific guidance/information on the areas of

direct interest to him without necessarily reading through the whole

document to get relevant information. It is, however, recommended that

the document is read through cover to cover at least once so that the

reader becomes familiar with the contents and their location. Thereafter

the document can be used largely as a reference book for specific advice/

information as required.

Chapters comprise a short introductory overview, followed by a series

of 2-page sections describing l^ey elements of planning, design or

operation. Wherever possible, a standard format of presentation has

been adopted for such sections. This is shown diagrammatically below.

As a consequence of the desire to have self-standing sections for easy

access by the reader, a certain amount of repetition/duplication

becomes unavoidable on topics which are closely related. The benefits

from the format adopted are, however, considered to outweigh this minor

disbenefit.

Road safety checklists have been provided as a free-standing chapter.

These are to be used to check that proposed infrastructure schemes do

not inadvertently include dangerous features which could be avoided

through better planning or design. If the answer to any of the questions

in the checklist is no, the reader is referred to the relevant sections for

further information on how road safety deficiencies can be rectified or

minimised.