Office of Operations
21st Century Operations Using 21st Century Technologies
Table of Contents

National Inventory of Specialty Lanes and Highways: Technical Report

Executive Summary

During the past few decades, transportation agencies have attempted to address road congestion and mobility challenges. Many agencies and authorities have adopted varying strategies to improve traffic throughput and enhance the serviceability of the transportation system. These approaches focus on implementing special lanes and highways with unique operational rules, such as access for carpools and vanpools, and varying pricing rate structures.

This report provides an inventory of ten classes of specialty lanes and highways; effectively any facility that is not typically for general-purpose use. The inventory summarizes operational specialty facilities from all 50 States and Puerto Rico and the facilities’ key characteristics. Researchers and practitioners may find this report useful for referencing the number of facilities by State and type, the entities that own and operate facilities, and general operating rules and vehicle restrictions.

Common examples of specialty highways include toll roads and managed lanes, such as high-occupancy vehicle (HOV), high-occupancy toll (HOT), express toll lanes (ETLs), and non-toll express lanes (NTELs). Some facilities are exclusive, e.g., bus-only lanes and truck-only lanes, where only specific vehicle classes can operate on roads. Some facilities permit vehicles to use the shoulder such as bus-on-shoulder (BOS) lanes, static part-time shoulder use (S-PTSU) lanes, and dynamic part-time shoulder use (D-PTSU) lanes. Priced managed lane facilities, such as HOT and ETL facilities, can provide time-reliable trips or revenue-generating opportunities to agencies that can support and maintain other transportation needs. One D-PTSU facility also has pricing; the I-70 Mountain Express Lane in Colorado only operates on weekends and holidays for a total of about 100 days per year—not a typical commuter schedule.

The project team performed an in-depth review of existing inventories, databases, and project websites. The team also conducted outreach to state and Federal representatives, tolling authorities, and project sponsors. Email correspondence and conference calls occurred with representatives to retrieve information.

The report includes a best effort State-by-State inventory of all currently operational (or operational at the end of calendar year 2019) specialty lane and highway facilities in the United States that the project team identified in its research. The inventory lists 502 facilities, with 463 publicly operated (by a public transportation agency or authority) and 39 privately operated (such as by a concessionaire). A facility is a distinct specialty lane or highway that operates within a given corridor. These facilities are owned and operated by 151 public- and private-sector entities. The entities include State agencies, local and regional authorities, city and county governments, and private companies.

Table 1 summarizes the number of each facility categorized by its principal operation, or purpose. Nine categories represent a group that can be collectively called managed lanes (explained and defined elsewhere herein) and the tenth category, toll roads, are legacy turnpikes, also discussed later herein. Whereas, the inventory includes toll roads, it does not list their additional characteristics beyond the project location (e.g., State, county, or region), owner, operator, and whether the facility is publicly or privately operated. Only facilities that operate on limited-access highways are included in the inventory, and not facilities on arterials.

Table 1. Inventory Summary by Principal Facility Type.
Type of Facility Abbreviated Name Number of Facilities
High-occupancy vehicle HOV 97
Bus-on-shoulder BOS 46
High-occupancy toll HOT 31
Express toll lane ETL 22
Static part-time shoulder use S-PTSU 13
Dynamic part-time shoulder use D-PTSU 6
Truck-only lane (or roadway) TL 5
Non-toll express lane NTEL 4
Bus-only lane, busway, or transitway BL 3
General toll facilities (turnpikes, toll roads, and bridges) Toll 275

Specialty lanes and highways currently operate in 39 States and Puerto Rico. Texas has the most with 68 facilities (inclusive of toll roads) followed by California with 67 facilities (also inclusive of toll roads). The remaining 11 states and four other territories do not have any operational or planned specialty facilities that operated at the end of 2019. Arizona, Connecticut, Tennessee, and Nevada only have HOV lanes, with no other type of specialty lane or highway. California has the highest number of HOV lanes, with 37 facilities out of 97 total HOV facilities in the United States. A total of 11 States and Puerto Rico have only toll roads and no other specialty lane facilities (e.g., no HOV, HOT, and ETL). Dynamic Part-Time Shoulder Use (D-PTSU) lanes are operational in 6 States, and 13 S-PTSU lanes currently operate across seven States. Minnesota, with 27 BOS, has developed the most extensive network of that group.

The inventory also lists the number of lane-miles and centerline-miles for each of the 502 specialty facilities and toll roads. For the purposes of this document, centerline-milesare the distance between two points along the median of a corridor, regardless of the number of lanes, and lane-milesare the cumulative distance of all lanes within the specialty road or lane group. For example, a 10-mile long HOV facility having one lane in each direction would have 10 centerline-miles, but 20 lane-miles. The inventory consists of a total of 5,326 lane-miles of specialty lanes (e.g., HOV, HOT, and ETL) and 25,496 lane-miles of general toll facilities (e.g., toll roads and bridges). Eight States, including Florida, Texas, New York, Oklahoma, California, Pennsylvania, Illinois, and New Jersey, have more than 2,000 lane-miles of specialty facilities and toll roads each, whereas 12 States have lengths of less than 100 lane-miles.

Tolling is the significant attribute for three of the ten types of specialty facilities; HOT lanes, ETL lanes, and toll roads. The inventory lists 54 distinct facilities with some element of pricing that is nota general toll road or bridge. Tolled facilities use one of three pricing methods:

  • Fixed pricing: a user pays a fixed toll price regardless of the time or day.
  • Time-of-day pricing: the toll price varies according to a specific schedule by time and day of the week (e.g., 8 a.m. on Monday).
  • Dynamic pricing: the toll price increases or decreases according to real-time demand, with higher toll prices usually occurring during peak periods.

Of the 54 priced facilities in the inventory, 31 are HOT and 22 are ETL, and one D-PTSU facility has pricing; the I-70 Mountain Express Lane in Colorado, which only operates on congested weekends and holidays to provide relief to ski areas and resorts. One facility (the Selmon Reversible Express Lanes on the Selmon Expressway in Tampa, Florida Metropolitan Region) has a fixed toll price, 13 facilities have time-of-day pricing, and the remaining 40 facilities have dynamic pricing. Many priced lanes require travelers to have a registered toll account and use a cashless toll transponder. A few facilities permit travelers to receive an invoice through the mail as part of a “Pay-by-Mail” option. Two HOV facilities operate on toll roads: the Dulles Toll Road in Northern Virginia and the SR 520 Bridge in Washington State. For these two facilities, drivers pay a toll to enter the limited access corridor, but they do not pay an extra toll to enter the HOV lanes.