Analysis of Risk Factors Influencing Road Crash Injury Severity in Urban Peshawar: A Random Parameters Logit Approach with Heterogeneity in Means and Variances

Abstract

Road traffic crashes leading to severe and fatal injuries over the years have been increasing rapidly, which is alarming and should be dealt with effective road safety countermeasures to enhance road safety. Road traffic crashes, being the 8th leading cause of death, justify the importance of road safety as a matter of great concern. Keeping in view the criticality of RTCs, the topic of road safety was taken under consideration. This current research study focuses on the influence of various risk factors related to injury severity caused by road traffic crashes in urban Peshawar. Crash data for the period of two years (2018–2019) were obtained from the district office of Rescue 1122, i.e., a leading emergency response unit. For the in-hand crash data, a random parameters logit approach taking into consideration the possibility of heterogeneity in means and variances of parameter estimates was deployed. The final chosen model was the “random parameters logit model with heterogeneity in means and variances” because of its statistical superiority over the other models that do not account for the possibility of heterogeneity in means and variances. For analysis and model calibration of road crash severity, three levels of injury severity outcomes are considered, namely minor injury, major injury, and fatal injury. The crash data incorporated various risk factors, mainly victims’ and driver’s attributes; details of weather and lighting conditions; posted speed limits; roadway type and geometry; reported reason of crash; vehicle type; and various other crash-related characteristics. According to the study findings, the likelihood of a fatal injury increases for crashes involving old age road users (above 60 years), crashes occurring at an intersection, crashes due to vehicle brake failure, crashes involving pedestrian collisions with a datsun, and crashes involving motorcycle and car collisions with (heavy vehicle) trucks and buses, respectively. Whilst the risk factors associated with an increase in viii major injuries include crashes involving middle-aged road users (18–30 and 41–50 years), crashes involving collisions of a motorcycle with Suzuki, Wagon, and Hiace, crashes involving motorists, crashes involving pedestrian collisions with Suzuki and Wagon, and crashes occurring due to motorcycle overspeeding. Furthermore, the likelihood of minor injury increases with crashes involving male road users compared to their female counterparts, drivers wearing seatbelts, involving collisions of pedestrians with rickshaws and motorcycles, and crashes involving collisions of passenger cars with Suzuki, rickshaws, and other passenger cars. The study's findings suggest that the public should be educated regarding road safety countermeasures by traffic police/wardens. Also, limit the use of heavy vehicles in the traffic streams, or they should be separated from the traffic streams within the city to avoid fatal crashes and provide separate facilities for vulnerable road users (pedestrians, motorcyclists, and bicyclists) to enhance the present road safety situation. Besides the aforementioned suggested road safety measures, some very basic and effective safety measures like seatbelt wearing, safe speed limits, and helmet use by motorcyclists should be adopted to improve road traffic safety effectively. Moreover, the findings of this research study will produce additional insights and interest in road safety that can be helpful for the infrastructure development authorities and highway agencies of the country, as well as for the law enforcement agencies in the enhancement of road safety through deploying the aforementioned counter measures.