Exploring the effects of the scheme allowing a proportion of solo-driving travellers to use HOV lanes on a single link

In order to improve the effects of High Occupancy Vehicle (HOV) lanes, we propose a scheme that allowing a proportion solo-driving vehicles to use HOV lanes. We use a system optimal model to describe the scheme on a long distance single link with a GP (general purpose) lane and a HOV lane. Then we applied the model to a numerical example to test the application. By analysis of the model, we found the relationship between the carpooling cost and operating cost, and the relationship between the capacity of GP lane and HOV lane in the case of system optimal when the proportion is 1 and 0. The results of the numerical example show the scheme is valid in reducing total travel cost, although might not by encouraging carpooling. And the carpooling cost and the occupancy, etc., are the key to consider when implementing this scheme.