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Engineering approach to accident prevention and reduction. KRTJ-5, Yogyakarta, 22-24 September, 1997

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TITLE: by: Engineering Approach to Accident Prevention and Reduction A Downing and H Iskandar Overseas Centre Transport Research Laboratory Crowthorne Berkshire RG45 6AU United Kingdom PA3304197 PA33304/97 DOWNING, A and H ISKANDAR (1997).Engineering approach to accident prevention and reduction. KRT-5, Yogyakarta, 22-24 September, 1997 Republic of Indonesia Ministry of Public Works Agency for Research and Development Isiueof Road Engineering Road Research Development Project Published Paper PA 6 ENGINEERING APPROACH TO ACCIDENT PREVENTION & REDUCTION by Andrew Downing Hikmat Iskandar Paper (Indonesiani version) presented at the 5th Konferensi Regional Teknik Jalan (KRTJ-5), 2 1-24 September 1997, Yogyakarta, Indonesia. ~ RANS OTT RESERCHTO LABORATORY Transport Research Laboratory, iil association United Kingdom. with PT Yodya Karya, In don esia. 11 -" ENGINEERING APPROACH TO ACCIDENT PREVENTION & REDUCTION List of Contents Page No. ABSTRACT 1 1. INTRODUCTION AND OBJECTIVES 1 2. THE MAGNITUDE OF THE ROAD ACCIDENT PROBLEM 2 3 . TOWARDS SAFER ROADS 3 3.1 An Integrated and Scientific Approach 3 3.2 Accident Prevention and Reduction 5 4. ROAD ACCIDENT PREVENTION BY IMPROVED PLANNING AND DESIGN 5 4.1 Background 5 4.2 .Safe planning of roads 6 4.3 Safe design of roads 12 5. ACCIDENT REDUCTION 1 8 6. EVALUATION OF ROAD SAFETY IMPROVEMENTS 22 7. CONCLUSIONS 24 8. ACKNOWLEDGEMENTS 24 9. REFERENCES 24 ENGINEERING APPROACH TO ACCIDENT PREVENTION & REDUCTION by A J Downing, Transport Research Laboratory H Iskandar, Institute of Road Engineering ABSTRACT Although road accidents are usually blamed on road users, it is evident that poor planning and road design will often have contributed to or compounded these errors. Indonesia, in common with other rapidly developing countries, has problems with inappropriate development along highways and outdated design standard. The introduction of modern accident prevention and reduction approaches should therefore have considerable potential for saving lives, injuries and property damage in Indonesia. The Institute of Road Engineering (IRE) has in collaboration with the Transport Research Laboratory (TRL), UK, initiated the development of a Mficrocomputer Accident Analysis Package and a black spot investigation and treatment methodology which has been applied in four trial areas. Also TRL has produced a Guide, Towards Safer Roads, and slide pack for planners and engineers to encourage both the safe planning and design of new road (Accident Prevention) and the effective treatment of existing roads (Accident Reduction). Indon esia has made a sound start but, given the rapid road development, these safety conscious approaches need to be adopted nationwide before it is too late. This paper outlines some of the key principles of the TRI, Guide. For example, land use planning and zoning to reduce travel and exposure of vulnerable groups to traffic, restricted access to arterial roads and avoidance of ribbon development, the establishment of road hierarchies with real functional and design differences, the provision of safe facilities for vulnerable road users, improved delineation and control of overtaking and speed. The principles are supported with examples and some evidence from case studies from Indonesia and South East Asia. 1. INTRODUCTION AND OBJECTIVES Studies of police road accident records show that, in all countries, the police typically identify the main cause of road accidents as human error. Indonesia is no exception with most of the accidents in 1995 being attributed to human error, and very few to road problems. Does this means engineers have no role to play in road safety ? No, far from It;, in many motorised countries engineers have led the attack on road accidents with outstanding success. Why then should engineers play a leading role in road safety ? There are four key reasons as follows. 1). Inconsistencies and complexities in the road design and road network will significantly increase the difficulty of the road users' tasks and result in more road accidents. 1 Cstfi.Krtj-5h.wpd25.06.97 2). Inappropriate planning of the road network in relation to land use and road function will unnecessarily expose road users, particularly the vulnerable, to the risk of road accidents. 3). Research in many countries (Downing, 1997) has shown that road planning, design and engineering countermeasures can lead to significant accident reductions and provide a more forgiving environment thus reducing the severity of injuries. 4). Road engineering improvements are relatively straightforward to implement and they usually have an immediate effect. Generally, road planners and engineers in the highly motorised countries have learnt from the mistakes made in the past and realised the potential of road safety conscious planning and design. However, most of their counterparts in developing countries are often still preoccupied with the problems of road construction and maintenance and increasing the network capacity. Thus, all too frequently, roads and road systems are being built or upgraded with little consideration given to road safety. As a result 'black spots' and 'black links' are created and many road users are being killed or injured unnecessarily. Therefore, the purpose of this paper is to bring road safety to the forefront of the minds of planners and engineers and to give examples of the key safety principles of accident prevention and reduction. The paper highlights the magnitude of the road accident problem in Indonesia and summarises some of the key principles from two key manuals ie the Transport Research Laboratory's (TRL, 199 1) "Towards Safer Roads in Developing Countries" and from the "Interim Manual on Accident Investigation Procedures and the Development of Low-Cost Engineering Improvement Schemes" produced jointly by Pusat Litbang Jalan (lIRE) and TRL (TRL/IR.E, 1993). It is important that these principles and approaches are verified in Indonesia conditions and the paper concludes with a review of the results of some road safety studies in the South East Asian region. 2. THE MAGNITUDE OF THE ROAD ACCIDENT PROBLEM The reported road accident statistics from the Indonesian Traffic Police Headquarters are shown in Table 1 together with vehicle data and an estimate for the 1995 casualties allowing for under-reporting of accidents by the public. From the table it is clear that vehicle registrations have increased by over 70 per cent from 1986 to 1995 whereas reported accidents have declined by 60 per cent, thus the accident rate has dropped forom 57 in 1986 to only 13 in 1995. The fatality rate has also declined but much more slowly than the accident rate and numbers of deaths have remained fairly stable with 1994 and 1995 having the highest figures in the last ten years. These figures overall look promising but there are two worrying features ie 1) the number of casualties per reported accident increased steadily from 1986 to 1993 and 2) the fatality index or the percentage of casualties who die in road accidents has increased steadily over 2 Csfi.Krtj-5b.wpd25.06.97 the last 10 years to a level which is nearly double that of ten years ago. These trends indicate that the accidents reported to the police are becoming more serious. This findin may reflect a real change in Indonesia, for example there may be an increase in the involvement of public service vehicles in accidents or vehicle occupancy levels may be increasing with a corresponding increase in passengers killed or injured. Alternatively, and this seems more likely, there may be a change in the public's accident reporting behaviour with an increasing tendency to report only the most serious accidents. Under reporting is clearly a characteristic of the road accident statistics in Indonesia and even deaths from road accidents are under estimated as the statistics are not updated for victims who die after they have been removed from the scene of the accident. The Hlighway Capacity Manual Project (SweRoad/Bina Marga, 1995) attempted to estimate the real magnitude of the problem in Indonesia using typical ratio's of Fatalities to other seventies of casualties based on Swedish experience. It was assumed that the minimum increase in fatalities was 50 per cent (similar to the Indonesia insurance claim statistics) and then other casualties were calculated using multipliers of the number of deaths. In Table I the same approach was used but the multipliers were based on those which applied to the UK in 1927 as these give a more conservative estimate of the number of casualties in relation to deaths. With these figures there were an estimated 478,065 casualties in Indonesia in 1995 compared with only 32,804 reported to the police le 93 per cent of the casualties are missing from the national statistics. This figure must be treated with caution and research is needed to compare hospital and medical cases with police cases to obtain a more reliable estimate of the real problem. Nevertheless the national statistics, even without correction, show a very serious problem as regards the fatality rate which is more than six times higher than that of the UK (see Table 1). 3. TOWARD SAFER ROADS 3.1 An Integrated and Scientific Approach It widely recognised that road safety is the responsibility of many sectors and that an integrated approach to national and local action is required. Remedial action is usually grouped under the 3 E's ie engineering, education and enforcement with additional concepts also recommended such as evaluation and encouragement. In order to successfully implement a multi-disciplinary action programme, a number of key requirements need to be met. The most important are: 1). A reliable and valid national road accident database 2). A national road safety plan based on a scientific and rational diagnosis of the road acci'dent problem. 3). National and local coordinating agencies with the necessary authority and resources to implement the plan. 4). Professional staff trained in the latest road safety approaches and technology. 5). Evaluation of the measures with feedback to the national plan. C:R~skfu 'n. Krtj-5b.wpd25.06.973 3 (0 ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~~~~~~~~0 *0 O0Z n v) ~ C - ~~ N~Z 00 0- c a 0 C- C~ n a ~ -- - - N - N - N - N - N - ' - C.)0 JO -ON N N-O U- Q en (N N C)4 -C' -00 -C) ~ ~ ~ ~ - 00 0 C c0~ ~ ~ ~ ~ ~ ~ ~ ~ ~~~~~~~~n 0 C) - Nol~ ') r 0Oo 0 p ' ~~c~' N~ ON ON - N- C) N i C O 00 0~~~0 r)(0. OC C) (N t OR, CC)C(N ( ON. (N N 00 - ON C) '/ 2 'r ,00 6' m 6' oc" m N 00 kn 00 ~ ~ ~ ~ ~ ~ N 0 - N ~~~~NO '/ ) ON 0 ) C) I I oe C' 6' ~ cJ) r-: C , - C) C)C4 - CA' C)0 en N 00 ( eN (N m ' N ') N Q ~~~ 00 ~ '/ 0 0 ON ~ ~c) O 'C) '0 N - 'rC) 'I ~~ ('NC) N cii- 0 0 (' C0- C ~ '.) c ~~ r'N0 0- N ( 0 N O OC ON r- - 00 o Ch 6 & oq m (N'", (N 0 0 0 C C - -z C G~~~~ C ~ ci,~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~Q ((N 00 ci, ci, C-e) -O CJ H ON'0'10 0~ Indonesia has taken a number of positive steps to reduce the road accident problem, for example there is a National Road Safety Plan and an improved accident information system known as Triple-L. Also the traffic law has been revised and trial black spot treatments introduced with evaluation carried out by Pusat Litbang Jalan (IRE). However there are still many potentially, highly effective measures and improvements for Indonesia to implement. Of course, care needs to be taken with the transfer of technology from one region of the world to another, but in the case of strategies and approaches to managing road safety, it is likely that these are applicable worldwide. Individual countermeasures or treatments on the other hand need to be appropriate for local conditions and integrated with other actions particularly publicity and possibly enforcement if they are to be successful. 3.2 Accident Prevention and Reduction An important road safety concept is the distinction between Accident Prevention and Accident Reduction. Accident Prevention involves improved planning and design of new roads and related developments to minimise road accidents and casualties. Not only are schemes designed wihsafety in mind but also they are checked by impartial safety specialists (road safety audit) to ensure that safety considerations have been met. Accident Reduction involves the application of cost effective measures to the existing road network particularly those sites, sections or areas with known accident problems. To encourage developing countries take up these approaches the Transport Research Laboratory (TRL) in collaboration with the Ross Silcock Partnership, developed a guide for planners and engineers (TRL/Ross Silcock, 1991) and a slide pack (TRL/Ross Silcock, 1994). Also the TRL, in collaboration with lIRE, produced an interim manual on the development of low-cost engineering improvement schemes (TRL/IRE, 1993) in order that a systematic approach for reducing road accidents at hazardous locations could be introduced in Indonesia. The next two sections of this paper summarise the key principles of these two manuals with examples. There are many other useful publications for road safety professionals and a selection of these is listed in the reference section of this paper. 4. ROAD ACCIDENT PREVENTION BY IMCROVED PLANNING & DESIGN 4.1 Background The Government of Indonesia is committed to major investment in expanding the road network and providing safe and efficient roads for the general public. It is therefore essential that safe planning and design practices are adopted. Table 2 shows some of the key characteristics of accidents found in 4 areas of Java (IRE, 1997). C:Rsztfelfii. Krtj-5b.wpd25.06.97 5 Table 2 Key characteristics of accidents in Java, 1993-95 The planning and design improvements should focus on reducing the main accident problems. From the Table, priority needs to be given to improving the safety of motorcyclists, pedestrians and buses particularly in areas of residential development both on urban and rural roads. The percentage of accidents occurring on rural roads with resdential land use is exceptionally high but not surprising given the ribbon development prevalent in Java. Indonesia's expansion of its road network provides an ideal opportunities to introduce safer planning and design practices. Some important strategies which need to be adopted are:. 1). Match the function, design and use of roads and classify roads into a hierarchy. 2). Provide road designs and environments which guide and match road user expectations. 3). Manage speed and keep speed below 30 kph where pedestrians share the road space with vehicles. 4). Control access and development to minimise high risk manoeuvres and exposure of vulnerable road users. 5). Provide a road environment which is forgiving and tolerant of human error. 6). Check schemes for safety at the various design and completion stages (safety audit) and modify as necessary. The "Towards Safer Roads" manual contains many principles, recommendations and examples and, given the space and time restrictions of this paper, only those most relevant to the Indonesian situation have been selected and described below. 4.2 Safe planning of roads The five priority components of safe planning are as follows. I). Road Hierarchy. The roads in a network should be clearly defined and classified into those which are primarily for movement (through traffic) and those which are primariily for local access. Some key principles are: 6 Csf fnKrj.j5b.wpd25.06.97 Percentage of casualties of Casualty/Accident Characteristic accidents _______________________________ Urban Rural 1. Casualties were: 1). Motorcyclists 40 25 2). Pedestrians 25 14 3). From buses/minibus 12 33 2. Accidents occurred: 1). Away from junctions 77 93 2). In residential areas or villages 65 89 3. Collisions were: 1). Head on 19 42 2). Side swipe 26 10 ________ _______ _______ 3). N ote to tail 21 17 Table 2 o Network hierarchy aids Development Control o Hierarchical levels assigned on intended or desired and not historical functions o Networks should create self contained zones to exclude extraneous traffic o Natural barrier effects of main routes can be used to segregate/contain incompatible uses o Appearance and design standards should clearly convey role of road and include appropriate speeds of traffic o Existing grid network layouts can be modified to hierarchical networks o Numbers, type and spacing of intersections should be consistent with expected traffic o Roads should intersect only with roads in same level or one level higher or lower in the hierarchy An example of an ideal hierarchy is shown in Figure 1. Figure 1 Ideal road hierarchy 2). Land use. Land-uses should be organised and controlled to minimise traffic and pedestrian conflicts and reduce the need for travel. Ideally people's work needs and shopping requirements should be located within safe walking distance of their homes. The key principles are: 0 0 0 0 C:1RszifAfti. Krtj-51b.wpd25.06.97 Control of land-use and traffic is vital Segregate incompatible uses Design networks to minimise conflicts Plan land-use to minimise travel and maximise accessibility to public transport 7 C:R~sif'e n. Kitj-5b.wj An example of unsafe and safer land use is shown in Figure 2 and the importance of development control in Figure 3. .q ' .... ..... Figure 2 Land use to minimise pedestrian conflicts Figure 3 Development control -A')n nA 07 ~~~~8 3). Access Control. Direct frontage or access onto major roads or near intersections should be minimised and not permitted at all at dangerous locations such as bends or hill crests. o Number of intersections should be minimised, junctions simplified and service roads provided o Traffic should work up through hierarchy of roads to reach primary road o Priority should always be given to road higher in hierarchy. All minor roads to have stop or give way marking/signs where they meet major road o Highway authorities must introduce control system which requires developers to get permission when they wish to access onto public roads o Small full-time development control team needed to assess/review access proposals -must have powers to enforce closures and remove illegal accesses o Access roads to parking areas of major facilities (hospitals, shopping centres etc) to be at least 50m from junctions An example of good and poor access control is shown in Figure 4. Figure 4 Access Control 4). Arterial Roads. Capacity expansion and rehabilitation projects must consider the existing usage of the road and ensure that the local user's needs and safety are maintained. The key principles are: C:Rskfe n. Krtj-5b wpd25.06.97 9 Where bypasses can be justified o Downgrade old road to discourage through traffic, reduce speeds and reinforce hierarchy o Provide only a few links from old road to new road, preferably via spur roads o Prohibit direct access from adjacent frontage land onto new road o Leave provision for future expansion of community but serve via spur roads 2. Where bypasses cannot be justified o Slow down through traffic speeds as it passes through community o Examples of techniques: - advance warning signs and rumble strips to warn of speed reducing devices ahead - chicanes, road narrowing or road humps to slow traffic where pedestrians predominate; and refuges where necessary - "gates" such as chicanes or road narrowing to alert drivers that they are entering low speed area o Provide urban high speed road along existing alignment only if separate service roads, restricted access, and grade separated pedestrian crossing facilities can be provided. The importance of speed control on arterial roads especially interurban roads passing through towns or villages cannot be underemphasised. An example of this type of problem is shown in Figure 5. Figure 5 Arterial roads 10 C:Rs~tie ii. Krtj-5b.wpd25.06.97 Figure 6 Speed reductions 5). Access and residential roads. Access roads should aim to provide a safe and comfortable environment for the local community particularly for the vulnerable road users. The key principles are: o0 Access roads should have safety, security, social and environmental issues as primary concerns o This can be brought about as follows: - vehicle flows minimised and unnecessary traffic eliminated - vehicle speeds kept low through appropriate design eg roads short (