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High-Occupancy Vehicle Systems

What Is an HOV Lane?

High-Occupancy Vehicle (HOV) lanes, also known as carpool or diamond lanes, is a traffic management strategy to promote and encourage ridesharing; thereby alleviating congestion and maximizing the people-carrying capacity of California highways.

  • HOV lanes are usually located on the inside (left) lane and are identified by signs along the freeway and white diamond symbols painted on the pavement.
  • In Northern California, HOV lanes are only operational on Monday thru Friday during posted peak congestion hours, for example: between 6 a.m. - 10 a.m. and 3 p.m. - 7 p.m. All other vehicles may use the lanes during off-peak hours. This is referred to as "part-time" operation.
  • In Southern California, HOV lanes are generally separated from other lanes by a buffer zone. The HOV lanes are in effect 24 hours a day, 7 days a week, referred to as "full-time" operation.

The operational practices vary differently between Northern California versus Southern California because of traffic volumes and commuter patterns in the two regions. Northern California highways usually experience two weekday congestion periods during peak morning and afternoon commute hours followed by a long period of non-congestion. Using a full-time operation would leave the HOV lane relatively unoccupied during off-peak hours and would not constitute an efficient utilization of the roadway. Southern California experiences very long hours of congestion, typically between six to eleven hours per day, with short off-peak traffic hours; part-time operation under these conditions would not be viable.

Why Build HOV Lanes?

According to California state law, the goals of HOV lanes are to reduce congestion and improve air quality on the State Highway System. The law states that HOV lanes are used "to stimulate and encourage the development of ways and means of relieving traffic congestion on California highways and, at the same time, to encourage individual citizens to pool their vehicular resources and thereby conserve fuel and lessen emission of air pollutants."

HOV lanes are a viable alternative, and in most cases is the only alternative, in meeting federal air quality conformity standards for capacity-increasing improvement projects in metropolitan areas. HOV facilities represent one approach being used in metropolitan areas throughout the state to respond to growing traffic congestion, declining mobility levels, air quality, and environmental concerns.

Who Can Use HOV Lanes?

Motorcycles, mass transit, and vehicles with two or more (2+) occupants are allowed to access the HOV lanes during their operational hours. An "occupant" is defined as any person who occupies a safety restraint device, i.e., seat belt.

Certain routes in the San Francisco Bay Area I-80 and I-880, Los Angeles I-10 El Monte Bus Way (during peak hour) and San Diego I-5 San Ysidro requires three or more (3+) persons per vehicle to access HOV lanes. Signs along the highway will specify the enforcement policy for each route. For San Francisco Bay Area ONLY, originally factory designed vehicles with a maximum two-seat occupancy may access the HOV (3+) lanes as long as there are two occupants in the vehicles.

Certain plug-in hybrid, alternative fuel and clean-air (ILEV/ULEV/SULEV) vehicles are exempted from the occupancy requirement. These vehicles can be distinguish by a green (plug-in hybrid) or white (clean-air) decal issued by the Department of Motor Vehicles.

The California Department of Transportation (Caltrans) has determined, as required by subdivision (g)(1) of Section 21655.5 of the Vehicle Code, that blood transport vehicles may now use HOV lanes without meeting occupancy requirements when transporting blood between collection points and hospitals or storage centers. The determination letter was shared with the California Highway Patrol and the Department of Motor Vehicles on July 14, 2022.

Motorcycles, public mass transit, and para-transit vehicles are also exempted from the occupancy requirement under California Vehicle Code §§21655.5 . Other bus services, such as school bus, charter, or sightseeing transports, are not exempted and must carry the minimum number of occupant to be eligible.

How Are HOV Lanes Enforced?

The California Highway Patrol (CHP) is responsible for HOV lane enforcement. The goal is to keep HOV violation rates to less than 10%. Once monitor counts detect violation rates above 10%, District personnel will notify local area CHP of the need for heightened enforcement in a particular HOV corridor. An HOV lane violation ticket is a minimum $490 fine. Fine may be higher for repeat offenders. In addition, at the discretion of the county's Board of Supervisors, local counties can assess additional administrative fees.

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