High-Occupancy Vehicle (HOV) lane programs are widely adopted in metropolitan areas in an effort to reduce congestion by encouraging carpooling. However, the operation of HOV lanes may result in traffic interactions that affect safety performance. In this paper, historical data from a number of freeway corridors in California are used to illustrate the distribution of collisions on different lanes on the freeway. The peak hours’ data, when compared to those in the non-peak hours, from all corridors indicate that more interactions due to traffic weaving near the HOV lanes might lead to a greater concentration on the inside lanes of the corridors. In addition, a comparison of corridors with continual access with those with dedicated ingress/egress sections also implies that the restricted entrance and exit into the HOV lanes could cause more intense and challenging lane-changing actions and subsequently a greater proportion of collisions near the HOV lanes. The collision data presented in this paper demonstrate the phenomena of collision concentration near HOV lanes, presumably caused by traffic merging and weaving. The results from this study provide valuable insights into the planning of HOV operations and in the identification of safety countermeasures for such facilities.
April 1, 2007