Modeling the Choice to Use Toll and High-Occupancy Vehicle Facilities

Traditionally, mode choice models distinguish between drive-alone and shared ride modes, leaving the network assignment models to predict the assignment of vehicles to toll and high-occupancy vehicle (HOV) facilities. If the shortest generalized cost path in the user equilibrium assignment is a toll or HOV path, the trip becomes a toll or HOV trip. Mode choice models that include the use of general-purpose highways, toll roads, and HOV lanes simultaneously with the choice of the drive-alone and shared ride modes are developed. Multinomial logit and nested logit models are estimated for this full set of alternatives. The models are estimated from a sample of data enriched by special surveys of toll, HOV, and transit users in the Houston, Texas, region. These data provide an empirical basis for studying the behaviors of toll and HOV facility users that is not normally available. The results indicate that the time saved by using these facilities has a higher utility weight than the time differences between other modes. Furthermore, for each mile traveled on a toll or HOV facility, there is an additional benefit that is partially offset by any excess in total travel distance necessary to use the toll or HOV facility. The additional preference for toll and HOV facilities can be explained by a perception of lower travel time, less driving stress, and higher reliability on these facilities. These results suggest that selection of a least-cost path in trip assignment is not sufficient for modeling the use of toll and HOV facilities.