DANISH ROAD TRAFFIC ACCIDENT INVESTIGATION BOARD

Transcription

1 DANISH ROAD TRAFFIC ACCIDENT INVESTIGATION BOARD Anne Eriksson, Traffic safety engineer, Anna Louise Feerup, Psychologist, Danish Road Directorate This paper presents The Danish Road Traffic Accident Investigation Board. Firstly the framework and the methods of The Board is described. Secondly, the findings from the Boards first theme, single car accidents with young drivers, are presented and some examples of its impact on road traffic safety work are mentioned. Finally, the recent theme, accidents on motorways, is presented in short. Presentation of the Board The Danish Road Traffic Accident Investigation Board was set up by the Minister for Transport in April The objective of the Board is to compile knowledge of road traffic accidents. Any new knowledge acquired is to be applied for the benefit of improved road safety. The Board is an interdisciplinary group, consisting of members engaged in in-depth analyses of frequent and serious types of road traffic accidents. The Board investigates the circumstances of individual accidents in order to form a precise picture of the underlying factors. The Board carries out analyses based on available material from the police, vehicle inspectors, road authorities, hospitals/casualty departments and the Department of Forensic Medicine. The Board uses the material to complement its own investigation of the vehicles involved and of the scene of the accident, and conducts interviews with the parties involved in the accident as well as witnesses, the police and the rescue team. The Board is commissioned to contribute with new or supplementary knowledge in road safety, which at the initiative of other institutions leads to preventive action against road traffic accidents. The object is not to determine the question of guilt or innocence in a legal sense. The Method The method used to analyse the accidents takes offset in the interplay between road user, road/road surroundings and vehicle immediately before, during and after the accident. The data used for the analysis is both collected from different authorities and collected by the Board itself. All data used 1

2 for the analysis is considered classified material and cannot be accessed by anyone but the Board. It is only the final report, the theme report, which is published. When the Board picks a theme to be analysed the following issues are considered: Is there a lack of knowledge in some special field? Is there a possibility to strengthen ongoing research or development? What themes are discussed in the media? What general trend do we see in the accident registration? The Minister of Transport himself can also take an initiative to ask the Board to analyse a given theme. To be able to collect and store the type of data required for the investigations the Board has asked for the necessary permissions from the Ministry of Justice, The Danish Research Ethics Committee and the Danish Data Inspection Board. Data Collection The Board cooperates with a number of Danish Police districts, the number and location can vary from theme to theme. When an accident occurs which is covered by the current theme, The Board receives police reports, sketches from the scene of the accident, photographs, criminal and licence records from those involved in the accident, information about the vehicles, autopsy reports and results from blood tests. The physician on the Board gathers further information from hospitals and casualty departments. Based on this material the physician makes an estimation of the relation between the injuries of the involved and the damage on the vehicles taking into account the impact of the safety equipment used. The engineer, the car inspector and the police member of the Board visit the site of the accident, preferably within three workdays after the accident. The site is then measured, photographed and traces of the accident are recorded. These can be marks on the wearing course, on the guardrails or on the roadside. The vehicles involved are also investigated when possible, and the information is compared with the information gathered at the site. The car inspector and the police use this information to come up with some conclusions about the collision; collision point, collision angle and the impact on the vehicle. This enables for calculation 2

3 of the speed and of the possible course of the accident. For this purpose a road-time diagram is used to illustrate the movements of the vehicles just before the impact. The road engineer of the Board contacts the local road authorities for information on road and traffic conditions. Information on earlier accidents on the same site is collected from the national accident database. The information gathered after the site visit is presented in a table for the other Board members; road conditions, sight conditions, road surroundings, traces of the accidents, traffic and speed conditions as noted on the site, marking and signing. A drawing is also produced to illustrate the conditions. The psychologist of the Board interviews those involved in the accidents and witnesses. Only those who agree and have the possibility are interviewed. In the interviews both objective and subjective data are collected. In the interview the following issues are covered: Driving experience, knowledge of vehicle, use of safety equipment, driving habits Traffic situation immediately before, during and after the accident, sight conditions, location of road users involved, possible distractors inside and outside the vehicle, the behaviour of the other road users, evasive action, point of collision and injury. The general conditions of the interviewed the days before the accident. Analysis Method The applied method of analysis serves to provide detailed information about the particular set of circumstances of the accidents and the factors accounting for their severity. The basis adopted for the approach is the interaction between the road user, the surroundings and the vehicle immediately before, during and after the road traffic accident. The results of the analysis serve to identify accident factors, i.e. factors that combined led to the occurrence of the accident, and injury factors, i.e. factors that were contributory causes to the severity of the accident. All the information gathered as described in the paragraph above is analysed to find the interaction between the road user, the road and its surroundings, and the vehicle, before, during and after the accident. In a given traffic situation the road user shall: Have access to the information needed to understand the situation. Perceive the necessary information. Interpret the information correctly. Identify his possibilities to react and take the right decision. 3

4 Pursue the right action. In the analysis it is estimated at which level it went wrong. On all levels it is estimated whether the error was due to road user, road/road surroundings or vehicle, or a combination of these conditions. When the course of the accident can be described and the analysis has been undertaken, the factors that contributed to the accident are identified. These factors are divided into two groups; accident factors and injury factors, as mentioned above. Most often there can be several accident factors contributing to the accident. The aim for each accident analysis is always to find the relevant factors in an objective way. In reality this is a difficult task and therefor it is based on best estimates. Here the interdisciplinarity of the group assures the quality of the analysis, and all the members have to agree on the final version of the analysis. Reporting The collected material on each accident is sent to all the members of the Board and forms the basis for the first round of report writing, the discipline reports. One member of each discipline group (police, engineer, physician, psychologist, car inspector) writes a report, based on the information adaptation model described above, with focus on his/hers special field of knowledge. A discipline report follows a fixed layout; a description of the accident and of the conditions for the analysis, an analysis of each step of the information adaptation process and a conclusion. Accident and injury factors are estimated and possible measures to avoid the accident and/or reduce the injury are suggested in the report. The discipline reports concerning one accident are discussed at a Board meeting, especially focusing on diverging points of view. On basis of the reports and the discussion an accident report is written, following the same layout, and describing conclusions and possible diverging points of view. Both the discipline reports and the accident reports are classified material and can only be accessed by the Board. The final report, the theme report, presents all the findings from the accident reports. In the theme report all accidents are made anonymous, i.e. it should not be possible to identify which specific accidents that have been analysed. The theme report represents the findings of the Board and is sent to the Ministry of Transport. It is also sent out to all those who were interviewed and to all others interested. 4

5 Findings from the First Theme, Young Drivers in Single Car Accidents One in four road traffic accidents with drivers under the age of 25 is a single car accident, i.e. an accident involving one vehicle only. For this reason the Board decided to focus on these accidents as its first choice of theme. 32 single car accidents with drivers under the age of 25 (3 female and 29 male drivers) were investigated, all of which took place in the autumn of A total of 69 people were involved in the accidents, either as drivers or passengers. 13 were killed, 47 were injured and 9 were not injured. Accident Factors Road user related traffic accident factors were found in all accidents in which speeding constituted the most frequent cause. In several cases the drivers had overrated their own skills and did not recognise potentially critical situations. Evidence of this was seen, e.g., in their negligence of the road or the surroundings, because they were busy with or distracted by something or someone inside the cabin. This negligence was commonly found to be resulting from the influence of alcohol, a known cause for reduced reaction. Drivers taking risks were found to occur in 12 accidents. 10 of these coincided with speeding, frequently in connection with having fun. Drivers thus engaged were in fact novice licence-holders, and in most cases their inexperience established an accident factor. Where the road or the surroundings proved to be the accident factor, one or more road user related accident factors were involved in each one. In some road traffic accidents the particular road design had appeared as a surprise to the driver. These cases would concern verge conditions when the drivers had gone off the road area, and the accident had occurred. In these accidents the drivers had reacted inappropriately when they hit the verge. The roadside design established the most significant accident factor in the road and surroundings category. In five accidents one or more accident factors were related directly or indirectly to the vehicle, and in all cases the speed limit was exceeded. In these accidents the drivers had been willing to take risks, and the driving of the vehicles had been most irregular, involving, besides speeding, worndown tyres and passing a sharp curve on a wet road, immediately before the accident occurred. 5

6 Injury Factors A little under two thirds of those involved did not use a seat belt. Unbelted driving could be expressive of a propensity to risk and a conviction that nothing will happen to me. 10 out of the 13 people killed did not use a seat belt. Estimates suggest that 8 out of the 10 people killed would have survived the accident if they had used a seat belt. In 19 road traffic accidents the fact that no seat belt was used added to the severity of the personal injuries. Speeding proved an injury factor in five road traffic accidents. In all these accidents the personal injuries would have been much less severe if the speed restrictions in force had been observed. Trees, ditches and other fixed objects especially in the safety zone 1 constituted a problem to the safety of road users. In a major part of the accidents investigated this made the accident much more severe than if the distance to fixed objects requirements had been observed. In three accidents defects in the vehicle were considered to be an injury factor. Findings and Recommendations Nearly all the accidents investigated had drivers in the years age group. Only three drivers in these 32 accidents were above the age of 22. This underlines the fact that young drivers and thus drivers with the least driving experience, or none at all lack practice and account for the highest risk of being involved in road traffic accidents. Driving lessons should to a greater extent strive to enable young drivers to better assess their own driving skills and should improve these skills especially when it comes to the handling of risks. A comparative study of the accidents by main purpose of the trip disclosed significant differences. For trips to or from a party or a discotheque the accidents occurred mostly between Friday night and Sunday morning as opposed to accidents during trips to or from work or leisure activities, or to or from visiting friends or family, typically taking place between Monday and Friday in the day-time. Accidents in connection with trips whose sole purpose was to have fun in the car and show it off to others were distributed more evenly over the week. The most frequent accident factors were speeding, negligence and drunk or drug driving. The accident factors were often connected. E.g., negligence was often due to the influence of alcohol or 1 The safety zone is an area along the side of the road whose design should prevent a vehicle going off the road inadvertently from overturning and being stopped so abruptly as to cause the persons involved to be seriously injured. 6

7 to passengers distracting the driver because of high spirits in the car. Speed limits were seldom observed. In 27 accidents the appropriate speed limit was exceeded. In 15 accidents speeding was up by over 40 per cent. This held true regardless of the purpose of the trip, but it was most predominant with drivers about to join or leaving a party. Drink driving was predominant as regards this purpose of the trip, and this was also the purpose of the trip for many of those who were killed, a total of 9 out of the 13 people killed. Nobody was killed in their way to or from work or leisure activities. 11 out of the 13 people killed were influenced by alcohol or drugs. In drink driving accidents, injuries became more serious as the body reacted less protectively to an outside energy impact than when sober. Legal initiatives and actions should be prepared in order to counter drink driving, speeding and failure to use seat belt. Particularly, considerations should be given to driving during weekends. Technical devices should be developed in motor car engineering to prevent drink driving and speeding and failure to use seat belt. Campaigns and police efforts aimed at young road users should target the youth cultures and motives for driving represented in the analysed accidents more precisely, thus addressing inappropriate driving behaviour and young drivers propensity to risk. Only in few cases were the road and the vehicle of any significance in the occurrence of the accident. The roadside design was found to be the most important single factor in accidents related to road surroundings. A situation would occur when drivers came partly onto the verge. The average car driver coming onto the verge with the right or left set of wheels would instantly reverse the motion of the steering wheel by reflex action. So did the accident drivers in the analysis. The softer the verge and the steeper the edges, the more extreme the driver s reversal. The road authorities should consider verge stabilisation. Fixed roadside objects aggravated personal injuries in 8 out of 10 accidents. In serious single car accidents the car often ended up clashing into trees, masts, walls, foundations, etc, or sliding into a ditch. In a major part of the accidents analysed the car had collided with fixed objects. 12 were killed and 34 were injured in these accidents. In the safety zone the fixed objects represented a particular problem to the safety of the road users. In many of the accidents investigated the vehicle collided with the fixed objects or ditches within the safety zone. As a result the accidents were made much more severe than if the distance to fixed objects requirements had been observed. The road authorities should give due consideration to relocating, removing or protecting fixed objects, particularly within the safety zone. 7

8 Technical measures in connection with road curve signs should thus be promoted. The Effects of the Theme Report The presentation of the theme report from this first theme gave many positive acknowledgements from the Ministries, the bodies working with Traffic safety and the media. There had been a lot of focus on young drivers and the report therefor came at a very suitable moment. Certain initiatives had already been taken to reduce the accident risk for this group but the report and its findings also gave way for further actions. Among these were: Increase of the penalty for reckless driving for new driver licence holders. Improvement of the driver school teacher training. Investigation on fixed roadside objects and how local road authorities should deal with this problem. Increased targeted campaign activities. As can be seen, the findings from the first theme were very useful and surely added facts to the ongoing debate on accidents among young drivers. The findings can also be used when planning future measures to reduce the accident risk within this group. However this type of investigation is quite extensive. 32 accidents have been investigated in the first theme and 39 in the second. Each theme takes more or less a full year from start of data collection to final report. But there is no easy way to find accident and injury factors. In Denmark the Police also used to register the dominant accident factors in the national accident database in the 70 ies. However this information proved of no value in investigations or research as it was too subjective and more served the function to place guilt. Since then the database only contains objective data concerning those involved, the road, the vehicles etc. The method used by the Board to find the factors which causes a certain type of accidents and their seriousness is indeed very thorough and time consuming but it is also one out of few scientific methods to do this. These types of investigations are essential in order to better understand accidents. By choosing a theme for the accidents that are to be investigated, the Board can focus its findings and also its recommendations. The themes also can be chosen from current topics in the media or problems seen in the accident statistics. The reasons for choosing the second theme, serious accidents on motorways, illustrate this. 8

9 The Second Theme, Serious Accident on Motorways As mentioned above the Board finished the first theme in the autumn of Currently, the Board works with serious injury accidents on motorways and the data collection period was September 2002 through February The theme report will be presented in late autumn The choice of the current theme is justified by: The number of accidents on motorways is increasing. The number of personal injury accidents are increasing. More persons are injured in each injury accident. A law proposal to increase the speed limit to 130 km/t is currently being discussed. The number of accidents with personal injury on the Danish roads has decreased by 35% during the last 12 years. On the motorways (some 1000 km) the number of personal injury accidents has increased in the same period by 85% and the number of killed has increased by 48%. In the year 2000 the Police registered 355 accidents with personal injury on the motorways. The explanation is partly that the total length of motorways has been augmented and that the traffic has increased significantly. The aim for this investigation is to uncover which accident factors are predominant in accidents on motorways and to try to come up with suggestions as to which measures could be used to reduce these accidents and their severity. References HVU - Single car accidents with drivers under 25 years (in Danish, English summary) The Danish Road Traffic Accident Investigation Board, report no. 1, 2002 How does The Danish Road Traffic Accident Investigation Board work? Article in Danish Road Review, January 2002 Links: (in Danish) 9