HIGHWAY TRAFFIC ACCIDENGT CAUSES ANALYSIS BASED ON EXPERT INVESTIGATION AND STATISTICS ANALYSIS METHOD Xu Nuo, Chen Lei Research Institute of Highway M.O.T, Road Safety Research Center M.O.T, 00088, Beijing China E-mail: nuo.xu@rioh.cn, l.chen@rioh.cn ABSTRACT A Highway traffic accident normally appears to be a random event, but also have its inevitability. Some potential factors hidden behind the appearance make such random events occur. There must be some relationship between the appearance and the factors of the accident. This paper will use expert investigation method to establish a check table to clarify the factors behind the appearances, find out the degree of contribution that such appearance made on reflecting the internal factors. Finally, combined with traffic accident statistics analysis on black-spots, calculate the scores of various causes. The higher score causes makes more effect for this black-spot. INTRODUCTION Many researchers believe that traffic accidents are caused by people, vehicles, road and environment factors, and "people" is the key factor to the accidents. The morphology of the accident, the accident vehicle, weather distribution, time distribution, seasonal distribution, velocity distribution is the external manifestations of a traffic accident. Traffic accident appearances are caused by people, vehicles, roads and environment factors. Through expert investigation method, establish a check-table to clear the causes behind the appearances. Through expert investigation method and analytic hierarchy process, find out the degree of the appearances contribution on reflecting internal causes. Combined the traffic accident statistics analysis on black-spots, calculate the scores of various causes. The higher score causes, the major reason for this black-spot. And finally, propose targeted improvement measures according to the main reason. ACCIDENT EXTERNAL MANIFESTATION After a traffic accident happend, traffic police department normally record the time, location (stake number), accident vehicle, and accident morphology of the accident. These records can be used as the traffic accident appearances. Through literature research and expert investigation method, determine the following six kinds of highway traffic accident appearances.. Morphology labeled A According accident morphology in People's Republic of Road Traffic s Statistics Annual Report, there are 8 accident morphology: A, Side collision;a, tag collision;a, concurrent scart;a, roll-over;a5, pendant car;a6, catch fire;a7, bump fixation;a8, bump fixation matter.
. Vehicle models labeled B According to Notice on Adjusting the Highway Traffic Survey Vehicle Classification and Conversion Coefficient [00]05 General Office of the Ministry of Transport, confirm 7 accident vehicle models: B, Small and medium-sized passenger cars;b, minivans;b, coaches;b, medium truck;b5, large freighted trucks;b6, extra large trucks;b7, container car. Weather labeled C According to the national standard QX/T8-007, confirm 5 weather phenomena: C, sunny; C, cloudy; C, rainy; C, snow; C5, foggy.. Time labeled D At different time periods of a day, the drivers have different driving states. hours a day will be divided into four stages: D, forenoon(06:00~:00); D, afternoon(:00~8:00); D, night(8:00~:00); D, before dawn(00:00~06:00)..5 Seasonal labeled E Drivers psychological and physiological are also affected by season. Consider seasons are the traffic accident appearances: E, spring(march to May); E, summer (June to August); E, autumn ( September to November ) ; E, winter ( December to Next February).6 Running Velocity labeled F According to Jia Yi and Dong Leihong s research result, if the difference between running velocity is over 0km/h, the possibility of traffic accident increases. 0km/h is used as a boundary value. The difference between different motors running velocity is over 0km/h, labeled F ; the difference between different lanes running velocity is over 0km/h, labeled F. ACCIDENT CAUSES Causes of traffic accidents usually analyze from four aspects: people, vehicles, road and environment. Through expert investigation method, find the causes hidden behind the appearance. According to the experts' experience, divide the factor of people (labeled a) into two parts: unsafe condition and unsafe behavior. Among them, the state of unsafe condition includes: a fatigue driving; a speeding (or relative to this area). Unsafe behavior includes: a overload; a Road-occupying; a5, illegal lane change; a6, illegal parking. Divide the factor of vehicles (labeled b) into: b, brake failure; b, steering failure; b, unexpected flat tire. Divide the factor of roads (labeled c) into: c, complex road alignment (including sharp bends, steep, long downhill, continuous curved or more of these road alignments combinations); c, friction coefficient; c, line-of-sight limited; c, roadside situation. Divide the factor of environment (labeled d) into: d, inclement weather; d, road environment.
RELATIONSHIP BETWEEN APPEARANCES AND CAUSES. Causes of Traffic s There must be some relationship between the appearance and the cause of the accident. Through expert investigation method, establish a check table to clear the causes behind the appearances including time, location (stake number), accident cars, and accident morphology. Table Causes of Morphology Table Causes of Vehicles Morphology Possible Causes A, Side collision a5,b,c,c,d A, tag collision a,a,b,c,d A, cocurrent scart a5,b,b,c,c,d A, roll-over a,b,c,c 5 A5, pendant car a,b,c,c,c 6 A6, catch fire a,b,d 7 A7, bump fixation a,b,b,c,c 8 A8, bump fixation matter a,a6,b,b,c,c Vehicles Possible Causes B,passenger car a,c,c,d B, jubilee truck a,a,b,c,c,d B, big bus a,a,b,b,c,c,d B, medium truck a,a,b,b,c,c,d 5 B5, large freight cars a,a,a,b,b,c,c,d 6 B6, large truck a,a,a,b,b,c,c,d 7 B7, container car a,a,b,b,c,c,d
Table Causes of Weather Table Causes of Time Weather Possible Causes C, sunny a,b,c C, cloudy a,b,c C, rainy a,c,c,c,b,d C, snow a,c,c,c,b,d 5 C5, foggy a,c,c,d Time Possible Causes D, forenoon ( a,b,c D, afternoon (:00~ 8:00) a,a,b,c D, night (8:00~ :00) a,a,b,c,c D, before dawn (00 a,a,b,c,c,d Table5 Causes of Seasonal Seasonal Possible Causes E, spring (M May ) a,b E, summer (J a,b,c,d August) E,autumn (September to November) a,b E, winter ( to Next Year s a,b,c,d February) Table6 Causes of Running Velocity Running Velocity Possible Causes F a,a,c F a,a,c
. Degree of the appearances contribution Through expert investigation method and analytic hierarchy process, calculate the degree of the appearances contribution on reflecting internal causes, as shown in Table7. Table7 the degree of the appearances contribution on reflecting internal causes N O. appearances A Morphology B Vehicles C Weather D Time E Seasonal 5 F Running 6 Velocity According to the result, value A to F: A, 0points points; E, 0 points; F, 0 points. contribution on reflecting internal causes (% ) 0 0 0 0 0 0 ;B, 0 points 5 CASE STUDY 5. Traffic s Statistics Analysis This article collects 0 accidents black section from 009, do the statistical analysis, such as table 8 to table shown. Table 8 Statistics of Morphology Morphology cocurrent scart Side collision tag collision bump fixation 0 bump fixation matter 5 5
Table 9 Statistics of Cars Table 0 Statistics of Weather Table Statistics of Time Table Statistics of Seasonal Cars medium truck 8 large truck passenger car 0 Weather sunny rainy snow cloudy Time 00:00~06:00 06:00~:00 :00~8:00 8 8:00~00:00 6 Seasonal Spring 5 Summer 7 Autumn 6 Winter 5. Causes After the traffic accident statistics of performance, it is concluded that the mainly accident morphology is following collision and bump fixation; mainly accident model is large car; the mainly weather is sunny; mainly happened in the morning; mainly happened in winter. Within the look-up table and table 6, it is concluded that causes of traffic accidents: A tag collision {a,a,b,c,d}, A7 bump fixation {a,b,b,c,c}, B5 large freight cars, B6 large truck {a,a,a,b,b,c,c,d}, C sunny {a,b,c}, D forenoon {a,b,c}, E winter {a,b,c,d}, F, F {a,a,c}. The collections of A and A7: {a,a,b,b,c,c,d}; The collections of B5 and B6{a,a,a,b,b,c,c,d}; The collections of F and F {a,a,c}. 6
According to the degree of the appearances contribution, calculate the score of the appearances, shown as table. Table the score of the appearances the appearances score a 00 a 0 a 60 b 90 5 b 70 6 b 0 7 c 90 8 c 0 9 c 50 0 d 0 d 0 As it shown in table, a speeding (or relative to this area), b, brake failure (or brakes less), and c, complex road alignment (including sharp bends, steep, long downhill, continuous curved or more of these road alignments combinations) are the main reason of the traffic accidents. 6 CONCLUSION Using the expert investigation and statistics analysis method, internal factors of an accident can be found by external manifestations. But according to the limitation of experts experience, there might be some defects in this method. On next level we can find the degrees of which factors would contribute on the reflecting internal causes, finally combined with traffic accident statistics analysis on black-spot, the major causes of traffic accident can be calculated. REFERENCES Jia Yi (007). Vehicle speed difference and Highway Traffic Safety Administration[C]. Energy conservation and environmental protection, harmonious development 007 Annual Conference Proceedings of the China Association for Science and Technology() Yang Bo(009). Applied Research for traffic accident statistics analysis in Highway security engineering [C]. China Highway management academic papers set (009). Shao Zufeng (00), Road traffic accidents cause analysis and security countermeasures[j]. Transportation Science Technology & economic.00():56~57. Lu Jianxin (008), Tian Jie. Analysis and Control Strategy of the causes of road traffic accidents[j],traffic Safety 008950:~. Fu Yinuo, Gu Fangping (00), Summary of Road traffic accidents cause theory[j]. Road Traffic and Safety.00(0):6~7. Wang Chaoshen (00). The road bend sections of road traffic analysis and security countermeasures[d]. Chang an University. 7
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