California High Occupancy Vehicle Facilities Degradation Report and Action Plan

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As required by Title 23 of the United States Code, section 166 (23 U.S.C. §166), Caltrans prepares the California High Occupancy Vehicle (HOV) Facilities Degradation Report and Action Plan. The Degradation Report identifies the degraded facilities on the State Highway System. The Action Plan details the actions Caltrans will take to make significant progress toward bringing degraded HOV facilities on State highways into compliance with the federal performance standard. These actions could include changes to the operations of the facility or other improvements.

HOV Facilities Degradation Reports and Action Plans


More information on degradation analysis and the action plan development process can be found in the HOV Degradation Action Plans Video.


HOV lanes were created to promote carpooling, reduce congestion, emissions, and delay, and generally provide a more reliable trip than one that may occur in the general-purpose lanes. The degradation performance metric ensures that HOV facilities will continue to perform as intended.

Section 166 of Title 23 of the United States Code includes a provision for public authorities to allow inherently low-emission vehicles (ILEVs), certain gasoline/electric plug-in hybrid vehicles, and toll-paying vehicles to use HOV facilities without meeting occupancy requirements. Public authorities that allow these exempted vehicles to access these facilities must monitor the performance of these HOV facilities and submit an annual report on the performance of these facilities to the Federal Highway Administration (FHWA).

California allows certain ILEVs and plug-in hybrid electric vehicles displaying valid decals issued by the Department of Motor Vehicles to access HOV facilities without meeting occupancy requirements. Currently, these vehicles are permitted on all HOV facilities on the State Highway System. California also allows toll-paying vehicles not meeting occupancy requirements to access certain HOV facilities, known as high-occupancy toll (HOT) lanes.

Federal law requires that vehicles in these HOV facilities must be able to maintain a speed of at least 45 miles per hour during weekday peak travel periods at least 90 percent of the time over a 180-day period. Any HOV facility that fails to meet this standard is considered "degraded." Federal law requires that the public authority with jurisdiction over a degraded HOV facility must develop a remediation plan that details the actions that will be taken to bring the facility into compliance with the minimum average operating speed performance standard. Failure to comply may result in federal sanctions and jeopardize states from receiving federal funds or project approvals.

Caltrans uses the Performance Measurement System (PeMS) to monitor and analyze the operational performance of HOV facilities. PeMS serves as a central repository to collect, store, and analyze traffic data from vehicles detection stations and traffic census stations. Traffic data is collected automatically from sensors located on or adjacent to freeways throughout the State. PeMS was used to collect the speed data for all HOV facilities except facilities in District 11. Facilities in District 11 are analyzed using the Ramp Metering Information System.

Caltrans collects data for every weekday for the period of July 1 to December 31. Speed data is collected from 6 a.m. to 9 a.m. in the morning and 3 p.m. to 6 p.m. in the afternoon as most HOV facilities in California operate during both time blocks.

The average speed of vehicles in the HOV facility is calculated and compared to the federal performance standard. If the speed of vehicles does not meet the federal performance standard, the HOV facility is considered degraded at that location. 

Caltrans further classifies degradation into three (3) categories based on how frequently it occurs. The three classes are defined as follows:

  • Slightly Degraded - degradation occurs from 10 to 49 percent of the time.
  • Very Degraded - degradation occurs from 50 to 74 percent of the time.
  • Extremely Degraded - degradation occurs 75 percent or more of the time.

HOV facilities that have degradation are analyzed to determine the potential causes, and this analysis is then used to guide the development of remediation strategies for the facility. These remediation strategies are then compiled into the annual Action Plan.

Federal law requires an action plan for each degraded HOV facility. The action details the steps that Caltrans will take to make "significant progress" toward bringing degraded HOV facilities into compliance with the minimum average operating speed performance standard. These actions include but are not limited to: increasing the occupancy requirement for HOV lanes; varying the toll charged to vehicles on HOV lanes; discontinue allowing non-HOV vehicles to use the HOV lanes; or increasing the available capacity of the HOV facility.

Maps of Degraded HOV Facilities

A map of the locations where degradation was observed on HOV facilities is provided as a supplement to the CA HOV Facilities Degradation Report. It shows the individual detection stations along the HOV facilities where degradation was observed and further categorizes the information by peak hour period and frequency of degradation. The map was created by the GIS Services Branch of the Office of System Management, Division of Traffic Operations, using the information provided from the CA HOV Facilities Degradation report. In addition to showing the locations where degradation was observed, the map also includes the bottleneck mapping from the most recent Mobility Performance Report. The purpose of this map is to provide a comprehensive spatial overview of where degradation was observed as well overall freeway performance in these areas.

Degraded Station Map Viewer

For further information on CA HOV Facilities Degradation Report, please contact Christian Clarion.