Overview
High-occupancy vehicle (HOV) lanes are restricted traffic lanes reserved at peak travel times or longer for the exclusive use of vehicles with a driver and one or more passengers. These often include carpools, vanpools, and transit buses. The normal minimum occupancy level is either two or three occupants. HOV lanes are typically created to increase average vehicle occupancy with the goal of reducing traffic congestion and related air pollution.
High-occupancy toll (HOT) lanes are restricted traffic lanes that are available to HOVs without charge; other vehicles are required to pay a toll that varies according to the time of day or according to real-time traffic conditions. Although numerous HOT lanes are operating in the United States today, none are operating parallel to an existing conventional toll facility. The concept of charging all customers a base toll, while designating an additional lane solely for HOVs and for SOVs willing to pay a higher toll, is untested in this country. This alternative would also create social justice issues with higher tolls being charged for patrons using the dedicated, additional lane.
As noted, no HOT lanes currently exist within conventional toll facilities in the United States. However, many of the components identified above can be observed at various facilities throughout the country. Some comparable facilities are identified below.
The concept of variable tolling is commonly applied at various managed lane facilities. Variable tolling by time of day or in response to real-time traffic conditions approach is employed on managed lanes on State Route 91 in Orange County, I-25 in Denver, the Katy Freeway in Houston, I-66 near Washington, D.C., I-495 on the Capital Beltway, I-95 in Miami, I-15 in Utah, I-15 in San Diego, I-580 in Alameda County, CA, and I-10/I-110 in Los Angeles.
Here, in looking at both HOVs and HOTs, the Study Team assumed that the Maine Turnpike would be widened to three lanes in each direction. Roadway widening alternatives are typically construction-based alternatives that require a fair amount of capital investment, including right-of-way acquisition. They sizably increase the throughput capacity (number of vehicles that can travel) of the roadway.
As part of the Portland Area Mainline (PAM) Needs Assessment, the Study Team assessed the potential results of converting an additional lane in each direction to either HOV or HOT usage from Exit 44 in Scarborough to Exit 53 in West Falmouth. They key components of this alternative would consist of:
- Widening the mainline of the Turnpike for approximately nine miles to provide a three-lane cross section in each direction with similar improvements as identified in Alternative 12 in terms of bridges, toll plazas, and local roadway intersections; and
- No barrier (either physical or painted) separating the HOV/HOT lane, which would allow maximum utilization.
This absence is not typical of most HOV/HOT facilities, which usually have a barrier or distance separation.
Read analysis
For more information, please read
The HOV/HOT Alternative: Working Paper