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Center for Advancing Research in Transportation Emissions, Energy, and Health (CARTEEH)

A USDOT University Transportation Center

Develop and Increase High-Occupancy Vehicle Lanes

High-occupancy vehicle (HOV) lanes aim to move people more efficiently by improving traffic flow by reducing congestion and encouraging carpools during peak travel times. HOV lanes are often open to carpoolers, buses, and sometimes electric or hybrid vehicles.1 Many states also offer HOV lane exemptions to further encourage the use of these lanes and reduce vehicle emissions.

Considering this strategy will help achieve the goal of the following objectives

  • Less Contamination
  • Less Emissions
  • Less Traffic Noise
  • Connectivity and Inclusion
  • Healthy Destinations
  • Less Traffic Violence
  • Active Transportation
  • Green Space

Transportation lifecycle phases

This strategy is associated with the following transportation lifecycle phases:

  • Construction
  • End of Life
  • Maintenance
  • Material Selection
  • Operations
  • Policy and Planning
  • Project Development

Who's involved

  • Car owners
  • Local governments
  • Transit agencies
High-occupancy vehicle (HOV) lanes aim to move people more efficiently by improving traffic flow by reducing congestion and encouraging carpools during peak travel times. HOV lanes are often open to carpoolers, buses, and sometimes electric or hybrid vehicles.1 Many states also offer HOV lane exemptions to further encourage the use of these lanes and reduce vehicle emissions.

How it Helps

HOV lanes can help reduce the number of vehicles on the road during peak commute periods, thus minimizing traffic congestion and lowering vehicle emissions by reducing fuel consumption.2 This can improve air quality, save energy use, and reduce commute times while still allowing road users to be connected to their destinations.

Implementing

Requirements and Exemptions:

The identification method for eligible vehicles and exemptions varies from state to state, so each municipality should consider who should be able to access the HOV lanes in the area.

Enforcement:

State or local police officers will be required to enforce HOV lane requirements. Some programs may also encourage self-reporting mechanisms by other commuters to report violators.

Design and Operation:

One important factor to consider during the planning of HOV lanes is how the HOV lane should be separated from the rest of traffic.3 For example, HOV lanes can be separated by concrete barriers or even be above or below the main road. HOV lanes can also be operated during different periods of the day, depending on commuter needs. The lane can be open 24 hours, only during peak hours, or during special events. Planners will also have to consider the number and placement of HOV lane entrances, as well as the lane endpoint, to maximize effectiveness of this intervention.

Examples

1) Houston Metro HOV Lanes

The Houston Metro offers HOV lanes that allows commuters to travel faster and avoid traffic congestion during peak hours. Carpoolers, vanpools, and motorcycles are allowed to ride the HOV lanes for free, while solo drivers also have the option to utilize the lanes if they pay a toll.

https://www.ridemetro.org/Pages/HOVandHOTLanes.aspx

1. Alternative Fuels Data Center. Alternative Fuel Vehicles and High Occupancy Vehicle Lanes. https://afdc.energy.gov/laws/HOV 
2. Boriboonsomsin, K., et al. (2007). Evaluating Air Quality Benefits of Freeway High Occupancy Vehicle (HOV) Lanes in Southern California. https://escholarship.org/content/qt8zr608dd/qt8zr608dd_noSplash_360920f0b246b318509ee1ecbfe50e4a.pdf?t=m5nvzh#:~:text=Vehicles%20traveling%20in%20HOV%20lanes,of%20traffic%20in%20the%20lanes.&text=On%20uncongested%20freeways%2C%20the%20travel,by%20HOV%20lanes%20are%20negligible.
3. Skowronek, D. A., et al. Dallas Area Guidance for HOV Lane Implementation. Texas A&M Transportation Institute. https://static.tti.tamu.edu/tti.tamu.edu/documents/7-4961-P1.pdf