Assessment of Crash Risks at Highway Access Points with Restricted Sight Visibility

Abstract

The paper describes an approach of crash risk assessment at midblock access points of highways where sight visibility is restricted due to inadequate corner clearance and also prevailing traffic is mixed in character. Field study was conducted at two junctions on two-lane highways and site details as well as associated traffic data were captured; proportion of two-wheeler and non-motorized vehicles was found to be significant at both the sites. A study of effects of mixed traffic on vehicle movements reveals that faster vehicles especially the bike riders often exhibit a tendency to swiftly overtake slower ones when they are impeded and accordingly sight distance needs for such vehicles increase to a considerable extent. Further, existence of vending shops at the corner of access points obstructs sight lines and reduces the sight distance available to drivers. On the basis of a descriptive statistical analysis, the paper demonstrated the effect of sight visibility on safety margins at access points. It was concluded that existence of vending shops significantly exaggerates crash risk at access points in the event of mixed traffic situations.