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.

The safety of both employees and the motoring public is of paramount importance to Caltrans, resulting in a continuing effort to improve the operating vehicle fleet. The potential safety changes that are the focus of this project are those that involve safety equipment enhancement over and above the original specifications for the vehicle or outside of the scope of the original equipment design or purpose, such as rear view backup video cameras.

The motivation for this project was Division of Equipment (DOE) managers' need for an objective strategy to address safety equipment deployment issues. These include determining where equipment changes should be made, whether statewide or only in specific locations, what types of vehicles will be involved, and how the changes should be made, for example, immediately retrofitting certain vehicles or changing the specifications for future vehicles.

Neither question needs to be answered on an absolute basis; for example, it may be appropriate to immediately retrofit particular vehicles in certain locations while changing the specifications for new vehicles to be deployed in other locations. Additionally, the problem may have non-equipment solutions such as changes to policies and procedures.