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National Inventory of Specialty Lanes and Highways: Technical Report

Chapter 4. Conclusion and Acknowledgements

Over the past 50+ years, many States and transportation agencies have adopted various managed lanes, defined and cited elsewhere herein as “highway facilities or a set of lanes where operational strategies are proactively implemented and managed in response to changing conditions.” In layman’s terms, and for purposes of this document, managed lanes may be thought of as “not general purpose lanes.”Along with longstanding toll roads (i.e., turnpikes) these are all collectively known as specialty lanes that address mobility and congestion challenges on freeways in the United States. High-occupancy vehicle (HOV) lanes were some of the first types of specialty facilities to operate in a few select States, beginning in the late 1960s. Over time, the early HOV lanes were joined by high-occupancy toll (HOT) and express toll lane (ETL) facilities as electronic tolling system technology advanced. More recently, States have developed yet other types of specialty facilities, including (bus-on-shoulder) BOS lanes, truck-only lanes (TLs), bus-only lanes (BLs), dynamic part-time shoulder use (D-PTSU) lanes, and static part-time shoulder (S-PTSU) lanes.

This report aggregate all of the Nation’s specialty highway facilities as of December 2019, using data collected from state websites, available databases, peer experts, and supplemented with proactive outreach. However, researchers and peers are encouraged to double-check your States’ inventories, and contact us with any perceived edits or additions. It is the authors’ intent to correct or improve this list from time to time, and we welcome your knowledge. Gathering and classifying information about specialty lane facilities required a considerable amount of effort and coordination from collaborating State departments of transportation (DOTs), Federal Highway Administration (FHWA) offices, and volunteers from several standing Transportation Research Board (TRB) committees. The authors wish to express our thanks for all of your input.

The project team prepared the inventory as a resource for the practitioner community as well as non-technical audiences curious about the national extent of specialty facilities. The inventory presents detailed records about each facility to increase awareness and understanding of unique lane and highway management strategies.

The inventory has 502 facilities managed by public and private operators. All of the facilities herein account for 8,248 centerline-miles and 30,820 lane-miles. Some 151 public agencies and private entities own and operate these facilities. The project team determined the 275 toll roads to be the largest sub-category; they exist in 34 States and Puerto Rico.  HOV facilities are the second most common specialty lane type outside of toll roads. California operates 37 HOV facilities, the most out of a total of 97 nationally. Four states (Arizona, Tennessee, Connecticut, and Nevada) operate only HOV lanes and do not have any other type(s) of specialty facility.

Over the past two decades, many States and partnering agencies have converted underutilized HOV facilities into HOT lanes by allowing single-occupant vehicles to pay a toll to travel on these facilities. Generally speaking (the reader is cautioned that exceptions may exist) facilities built as HOV lanes must continue to allow qualifying HOVs free access should those lanes ever be converted to HOT lanes (23 U.S.C. Section 166).  Only three sub-categories of the ten categories in this list involve tolling. They are HOT lanes, Express toll lanes, and toll roads, also known as turnpikes. Toll prices are set based on one of three pricing methods: all-day fixed, time-of-day, or dynamic pricing. ETLs function similarly to HOT lanes except that they do not exempt carpools (i.e., HOVs). As of December 2019, 40 HOT and ETL facilities have implemented dynamic pricing as a means to mitigate congestion and generate revenue for a wide number of uses.

Beyond the three priced facilities; the project team identified seven other types of specialty lanes:  HOV lanes, non-toll express lanes (NTEL), bus-on-shoulder lanes (BOS), part-time static- and dynamic shoulder use lanes, truck-only lanes (TLs), and bus-only lanes (BLs). From the research, at least four NTELs operate in States that offer travelers a choice to attempt to bypass local traffic without paying a toll. Integrating shoulders as peak-hour congestion relief travel lanes is becoming an option for more and more States. As of December 2019, 46 BOS, 13 S-PTSU, and 6 D-PTSU facilities are in operation across 17 States. Usually, specialty shoulder facilities operate during peak periods in the peak direction of flow. Specialty shoulder facilities in the United States account for 345 center-miles and 494 lane-miles of freeways.

Caltrans implemented five truck-only lanes on I-5, I-15, and SR60 in Los Angeles, San Bernardino, Riverside, and Kern Counties. Bus-only lanes operate on SR-15 and SR-163 in California and on I-495 in New Jersey as a connector to a tunnel.