Effects of lane marking restrictions on driving safety of professional drivers at highway merging area in Hong Kong.

Abstract

A merging area is one of the crash-prone locations in a highway network because of frequent lane changing, weaving, and merging behaviors. In Hong Kong, specific lane marking is implemented to guide traffic movements by keeping vehicles in designated lanes, reducing weaving, and channeling traffic. Therefore, conflicting traffic movements can be separated, and overall operational efficiency can be enhanced. However, the effects of traffic channelization through lane marking restrictions on the occurrence of traffic conflicts and associated risks to driving safety are less explored. In this study, the influence of lane marking restriction on traffic conflict risk involving merging traffic is investigated using vehicle trajectory data obtained from unmanned aerial vehicles. In particular, a two-dimensional modified time-to-collision-based indicator is applied to model traffic conflict risk involving lane-changing vehicles at a highway merging area. In addition to lane marking restriction, the influences of confounding factors including vehicle class, vehicle dimensions, and speed and acceleration profiles are also considered. A random parameters logit model with heterogeneity in means is then employed to account for the effects of unobserved heterogeneity. Results indicate that both-side restricted situation significantly reduces traffic conflict risk by limiting all lane-changing behaviors. Additionally, one-side restricted situation also exhibits favorable, even less remarkable, effect on traffic conflict risk. Furthermore, traffic conflict risk decreases for trucks because of the compensatory driving behavior of professional drivers, while the favorable effects of goods vehicles on traffic conflict risk are random. Nevertheless, the random effects of trucks can be moderated by lane change restrictions and lane changing behaviors. Findings should shed light on effective mitigation measures and traffic control strategies that reduce potential crash risk at the highway merging areas.