University of California Transportation Center

This dissertation compares the effects of HOTLs, congestion toll lanes, GPLs and HOVLs. A deterministic travel-demand model that estimates the comparative travel times under competing investment scenarios is adapted here to consider how tolls influence ridesharing. The results indicate that HOTLs, congestion toll lanes and GPLs provide a greater degree of system-wide delay-reduction benefits than HOVLs in most cases. Furthermore, when maximum mainline peak highway delays are between 20 and 40 minutes, congestion toll lanes provide a greater reduction in overall delays and emissions than GPLs.

This research provides support for the policy claim that in almost all local urban travel conditions, HOT lanes provide a greater degree of fiscal, consumer welfare, and environmental benefits than all other life-haul urban expressway investments. HOT lanes are the only urban highway facilities capable of withstanding induced growth effects, and preserving congestion-free service after an initial reduction in travel costs. In the few cases in which the delay reduction benefits of toll lanes and GPLs are roughly comparable, the revenue-producing nature of toll roads greatly lowers the comparative social cost of long-term highway maintenance and rehabilitation. Although the HOT lane capital costs are significantly higher than HOV lanes, a 10-mile HOT lane facility can provide up to $20 million in annual revenue (in 2000 dollars). Because HOT lanes preserve congestion-free service in the face of traffic growth, HOT lanes are more environmental beneficial than either HOVLs and GPLs. This research provides support for federal policies that expand the use of tolling on urban interstate highways, especially in non-attainment areas where states are ineligible for new highway construction funds.