Research On Traffic Safety Evaluation Of Mountainous Expressway Tunnel Based On Historical Crash Data

In recent years,more and more attention has been paid to tunnel traffic safety.However,studies on tunnel traffic safety in China have been somewhat lacking.The commonly used method of tunnel traffic safety evaluation is based on system thinking,taking the four factors into consideration: human,car,road,and environment.Most of the data used in this method come from expert ratings,and the data are more or less subjective.Based on the historical data of highway tunnel traffic accidents,this paper studies the evaluation index and evaluation method of tunnel operation safety,which provides the basis for improving the traffic safety research of highway tunnels.First of all,the historical data of tunnel traffic accidents are analyzed,and the basic characteristics of tunnel traffic accidents are obtained.On the feature of time distribution,the number of accidents in October is the most,the number of accidents in March is the least,and the number accidents on weekends is higher than that on working days;the accident is mainly concentrated in 10:00~12:00 and 15:00~17:00.In terms of spatial distribution characteristics,traffic accidents in tunnels are mainly concentrated on the fisrt 100 m inside the tunnel.In terms of vehicle type characteristics,tunnel accidents mainly involve cars and trucks.In the distribution characteristics of the type of accidents,the number of rear end accidents is the most.Secondly,according to the main traffic safety index of tunnel(accident rate and accident severity)and traffic accident data,the accident rate is divided into the accident rate in recent 6 years,the accident rate in recent 5 years,the accident rate in recent 4 years,the accident rate in recent 3 years,the accident rate in recent 2 years,and the accident rate in 1 years.Meanwhile,the accident severity is divided into 4 indicatiors: the number of deaths,the number of injuries,the number of vehicles involved and the number of major accidents(fire accidents,bus accidents and dangerous chemical vehicle accidents).According to these 10 two grade indexes,the single index of the tunnel is classified,and the results are similar to the 6 two grade indexes of the tunnel under the accident rate,but the ranking results of the tunnel under the severity of the accident severity are inconsistent,which indicates that the tunnel traffic safety should be comprehensively evaluated by multiple indexes.If a single two level index is selected as the ranking index,the accident rate in the recent 6 years should be chosen in order to make full use of the accident data.Then,a comprehensive evaluation of tunnel traffic safety is conducted.The comprehensive evaluation study selects the entropy weight method,the Analytic Hierarchy Process(AHP)and Technique for Order Preference by Similarity to Ideal(TOPSIS).According to the combination of these three methods,entropy weight-TOPSIS comprehensive evaluation method,AHP-TOPSIS comprehensive evaluation method and entropy-AHP-TOPSIS comprehensive evaluation method are formed.Finally,the three comprehensive evaluation methods are verified by examples.The three comprehensive evaluation methods show that the weight of the death toll is the largest,and the results of the tunnel evaluation are similar.The three comprehensive evaluation methods are compared and analyzed.The weight value of the index obtained by the entropy-AHP-TOPSIS comprehensive evaluation method is between the values obtained by the other comprehensive evaluation methods,combined with the opinions of the local experienced managers,it is preliminary judged that the entropy-AHP-TOPSIS comprehensive evaluation method is more suitable for the comprehensive evaluation of the tunnel traffic safety.