Impact of vehicle type on stopping sight distance at signal-controlled intersections in heterogeneous traffic conditions

摘要

Road safety is one of the predominant public health responsibilities among traffic engineers, and it requires high attention. The sight distances play a crucial role in the highway geometric design. Among all the sight distances to be provided, the stopping sight distance is highly important in the geometric design of roads. The traffic volume in heterogeneous traffic conditions is broadly classified into five categories: two wheelers, three wheelers, car, LCV, and HCV. The highway capacity manual (HCM Transportation Research Board: National Research Council, Washington, DC 2010) introduced the concept of passenger car units, to convert different vehicle types into single vehicle category. Even after the introduction of PCU, the stopping sight distance for different vehicle types is considered as same value, because there is no other factor accommodating for vehicle type. In real traffic scenario, the physical characteristics of vehicles such as length and width are different for different vehicle categories. So, in order to understand this problem, the study focusses on impact of vehicle type on stopping sight distance of vehicles. For this purpose, the data were collected at intersections using both video graphic technique and OSM (Open Street Map) tracker. The field measured stopping sight distances are modeled considering the vehicle type, and the developed models are validated. The study results showed that two wheelers require higher Stopping Sight Distance compared to other vehicle categories and Light Commercial Vehicles (LCV) require least sight distance. Also, the results of the present study are helpful in assessing the safety analysis of vehicles.