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Washington State Freeway HOV System

Photo of HOV lane on highway
Washington State has invested more than 1.5 billion of state and federal dollars in freeway HOV lanes and ramps over the past 40 years.

Thumbnail of HOV system map
WSDOT map of the HOV system in the central Puget Sound area. Approximately 310 lane-miles of a planned 320 mile freeway system have been built since 1970. See the larger interactive HOV webmap.
What are HOV lanes?
Where are freeway HOV lanes located?
When do freeway HOV lanes operate?
Why do we have freeway HOV lanes?
How do freeway HOV lanes work?
How well is the freeway HOV system working?
What is in the future for freeway HOV lanes?
How can I get more information?


What are HOV lanes?

HOV lanes are high occupancy vehicle lanes, also known as carpool or diamond lanes. The HOV system consists of a network of special-use freeway lanes which connect major population and employment centers. It forms a crucial part of the central Puget Sound area's highway system, carrying more than 1/3 of freeway travelers during rush hours. Approximately 310 lane-miles of a planned 320-mile freeway system have been built.

Freeway HOV lanes are generally inside (left) lanes and are identified by signs along the freeway and diamond symbols painted on the pavement. They are typically separated from the other lanes on the freeway by a solid white line.

HOV and HOT lanes are a key component in Moving Washington, a program to fight congestion and improve performance of the entire transportation system.

Where are freeway HOV lanes located?

HOV lanes are located on most of the major freeways in King County and southwest Snohomish County. The HOV system is currently being expanded into Pierce County. See the HOV webmap to see where freeway HOV lanes are currently located, and where they are planned for the future.

HOV lanes run in both directions on I-5 between Everett and Northgate. They exist only intermittently on I-5 between Northgate and downtown Seattle. On the mainline, there is a southbound HOV lane in the Seattle downtown area from approximately Denny to Marion, and then from I-90 southward. In the northbound direction, the mainline HOV lane ends just before I-90, and then does not begin again until Northgate. There are also HOV lanes located in the Reversible Express Lanes on I-5 between Northgate and downtown Seattle.

HOV lanes run the entire length of I-405 in both directions and exist only intermittently on I-90 between Bellevue and Seattle. There is a westbound HOV lane on the outer mainline roadway between Bellevue Way SE (in south Bellevue) and 80th Avenue SE (on Mercer Island). There are also HOV lanes located in the Reversible Express Lanes on I-90 between south Bellevue and downtown Seattle.

HOV, transit-only, and business access and transit (BAT) lanes also exist on many arterials and city streets throughout the central Puget Sound area. Information on those lanes is available from local jurisdictions.

When do freeway HOV lanes operate?

HOV lanes on the west side of Lake Washington operate 24 hours a day, seven days a week. HOV lanes on eastside freeways are open to all drivers at night.

Direct access ramps are restricted to carpools, vanpools, buses, and motorcycles all the time, even when HOV lanes are open to other traffic at night. Direct access ramps at Ash Way are restricted to buses-only for safety reasons.

The following HOV operating hours are in effect seven days of the week unless otherwise noted:

  • I-5: 24 hours a day. See special hours of operation in the I-5 reversible express lanes between Northgate and downtown Seattle.
  • I-90 (east of I-405): 5 am – 7 pm.
  • I-90 (west of I-405): 24 hours a day. This applies to the westbound HOV lane on the outer mainline roadway, from Bellevue Way SE in south Bellevue to 80th Avenue SE on Mercer Island. See special hours of operation for the I-90 reversible express lanes in the center roadway between Bellevue and Seattle.
  • I-405: 5 am – 7 pm.
  • SR 16: 24 hours a day.
  • SR 167: 5 am – 7 pm. HOV lanes on SR 167 have been converted to HOT lanes between Renton and Auburn, but the operating hours remain the same. Between 7 pm and 5 am, the lanes are open to all toll-free.
  • SR 520 (east of I-405): 5 am – 7 pm. Note that unlike the rest of the system, HOV lanes on SR 520 are on the right side of the general purpose lanes.
  • SR 520 (west of I-405): 24 hours a day. The SR 520 HOV lane requires three or more people west of I-405. Note that unlike the rest of the freeway HOV system, HOV lanes on SR 520 are on the right side of the general purpose lanes.
  • Direct access ramps (all): 24 hours a day, even when HOV lanes are open to all traffic. Note that direct access ramps at Ash Way are restricted to buses-only.

Hours are shown graphically on the HOV webmap. When HOV lanes are open to all traffic, they should be treated as a regular left-side freeway lane. Left-side freeway lanes are normally reserved for passing.

Why do we have freeway HOV lanes?

HOV lanes increase freeway efficiency by moving more people in fewer vehicles than the full lane next to them. They save time for bus riders and carpoolers by enabling them to bypass areas of congestion. They enable commuters to get to work more quickly and provide an incentive to take the bus, carpool, or vanpool anytime during the day. They help buses stay on schedule and provide access for emergency vehicles when needed.

How do freeway HOV lanes work?

Who can use freeway HOV lanes?

Drivers can use HOV lanes whenever there are two or more people (including the driver) in the vehicle. The definition of "people" is not limited by age or licensing status. Hybrid and other green vehicles are required to have the same number of occupants as other vehicles in the HOV lanes. Trucks are limited to 10,000 pounds gross vehicle weight, but there is no weight limit for recreational vehicles or buses. Towing is allowed in the HOV lanes as long as an adequate speed can be maintained and the combined weight does not exceed 10k.

Buses, emergency vehicles, and motorcycles can use freeway HOV lanes, regardless of how many people are on board.

Who cannot use freeway HOV lanes?

  • People driving alone, except as noted above.
  • Solo drivers who are passing another vehicle in the adjacent general purpose lane.
  • Solo drivers in hybrid or other green vehicles.
  • Trucks which weight more than 10,000 pounds gross vehicle weight.
  • Vehicles pulling a trailer when the total weight of both vehicles is more than 10,000 pounds gross vehicle weight, or when the combination is unable to keep up with the flow of traffic in the HOV lane.

The above restrictions are in place to help maintain the reliability and safety of the lanes.

How do I use freeway HOV lanes?

Vehicles carrying the required number of people may enter or exit an HOV lane wherever there is a single line separating the HOV lane from the lane next to it. Vehicles may not cross double lines.

There are only three exceptions:

  • SR 520, west of I-405. This is the one place on the HOV system where three or more people are currently required. The 3+ occupancy requirement on this segment has to do with safety concerns.
  • I-90 Reversible Express Lanes, west of Island Crest Way. Single occupant vehicles traveling between Seattle and Mercer Island (and vise versa) are allowed to use the I-90 HOV Reversible Express Lanes in the center roadway. Solo drivers may use the I-90 HOV Reversible Express Lanes between Rainier Avenue S (Exit #3) and Island Crest Way (Exit #7) in either direction. They cannot use the HOV lanes east of Island Crest Way on Mercer Island, or the lanes west of Rainier Avenue S in Seattle. Note that the new I-90 westbound HOV lane between Bellevue and Mercer Island on the outer roadway is restricted to HOV-only at all times.
  • SR 167 between Renton and Auburn. These HOV lanes were converted to high occupancy toll or HOT lanes in 2008. Single occupant vehicles with a transponder may use these lanes for a toll when there is room.

How are freeway HOV lanes enforced?

Enforcement of freeway HOV lanes is the responsibility of the Washington State Patrol. Although safety-related activities take priority, the State Patrol enforces the HOV lanes as much as possible. An HOV lane violation ticket costs $124. You can help the HOV system through the HERO program, where citizens can report the license plate number, vehicle description, time of day, and location of any violators they see. You can report violators by calling 1-877-764-HERO or by filling out an online dispute violation form.

How well is the freeway HOV system working?

HOV lanes move about 35 percent of the people who use this area’s freeways in only 19 percent of the vehicles. The average HOV lane carries more than 1½ times as many people as the average “regular” lane, and is saving users time on each freeway. (Averages based on 2007 peak commuting periods and directions.)

The freeway HOV system enjoys a high level of popularity with the majority of freeway users in the central Puget Sound area. A public opinion poll (pdf 84 kb) done in 2007 by the University of Washington showed that 76% of freeway drivers who do not usually use the HOV lanes still thought HOV lanes were a good idea. 66% of this same non-user group felt that HOV lane construction should continue, and 62% disagreed with the idea of opening the HOV lanes to everyone all the time. Also, Puget Sound enjoys one of the lowest HOV lane violation rates in the nation.

What are the benefits of freeway HOV lanes?

  • Efficiency. HOV lanes increase freeway efficiency by moving more people in fewer vehicles than the full lane next to them.
  • Travel Time Reliability. HOV lanes help express buses stick to their schedules. Carpools, vanpools, motorcycles, and emergency vehicles also receive a quicker trip.
  • Speed, Ease & Money. Users cite saving time and money, reduced stress, and convenience as the main reasons they use the HOV system.
  • Freeway Demand. HOV lanes reduce competition for a limited amount of space on the freeway during rush hours.
  • Fewer Cars Area-Wide. HOV lanes add fewer car trips to the transportation system than new general purpose lanes.
  • Greenhouse Gas Emissions. If we add fewer car trips, we help to decrease new greenhouse gas emissions and place less of a burden on the environment.
  • Sustainability. HOV lanes play a crucial role in helping to support more sustainable transportation choices by providing an incentive to carpool, vanpool, or take the bus.

What problems is the freeway HOV system experiencing?

The freeway HOV system is very well utilized during the seven hours per weekday that are considered peak commuting periods: 6-9 am and 3-7 pm. These typical peak hours often spread into the early morning, mid-day, and evening hours, when HOV volumes can be high as well. In many locations there is high demand for HOV lanes in both directions, not just the “main direction” of travel during each peak period.

The HOV lanes on I-5, I-405, and westbound SR 520 are so well utilized that they are usually congested during the peak periods and no longer meet our established performance standard of 45 mph. This makes it difficult for express buses to stick to their schedules, impedes speed and travel time reliability for vanpoolers and carpoolers, and reduces the incentive for all users to share rides. WSDOT is working to address both over- and under-use of freeway HOV lanes through conversion of HOV lanes to HOT lanes.

What is in the future for freeway HOV lanes?

Population in the Puget Sound area is expected to increase by about 1.7 million, and the number of jobs by about 1.2 million, over year 2000 levels by 2040. Our general purpose lanes, and most of our HOV lanes, are congested during the peak periods, and those peak periods are becoming longer all the time.

New approaches, like active traffic management, tolling, innovative technology, and other congestion management tools will be necessary to help keep everyone moving. For a list of solutions by corridor, see the Moving Washington program. Meanwhile here are some other measures being taken:

New HOV Lanes

Approximately 310 miles of a planned 320 mile freeway system are complete. About two miles of new HOV lanes are currently under construction on SR 520, expanding the system east to SR 202. Six miles of new HOV lanes are currently under construction on I-5 and SR 16 in Pierce County. The SR 167 southbound HOT Lane is also being extended a short distance north to I-405.

HOV lanes opened in the last five years include:

  • A westbound HOV lane on I-90 between Bellevue and Mercer Island on the outer roadway (Oct 2008).
  • HOV lanes on I-5 in Everett between SR 526 and SR 2 (Jun 2008).
  • HOT lanes on SR 167 between Renton and Auburn (May 2008).
  • HOV lanes on the Tacoma Narrows Bridge (July 2007).
  • HOV lanes on I-5 between Federal Way and the Pierce/King County line (May 2007).
  • HOV lanes on I-5 between the Pierce/King County line and the Port of Tacoma Road (November 2010)
  • HOV lanes on SR 16 between Union Avenue in Tacoma and Olympic Drive NW in Gig Harbor (Jan 2007).
  • Ten direct access ramps at various locations. 

New HOV Ramps

Up to 21 possible locations have been identified for construction of direct access ramps to improve freeway travel time and safety. Direct access ramps drop HOV traffic directly into the HOV lane, removing the need for HOVs to weave across the freeway. They improve travel time, safety, and reliability for all freeway users by providing a more direct way for HOVs to get in and out of the center lanes.

Ten of these ramps have already been built. These ramps are being planned and constructed in partnership with Sound Transit and other agencies. They are producing travel time savings of up to ten minutes per trip and creating smoother driving conditions for both HOVs and surrounding traffic.

Conversion of HOV Lanes to HOT Lanes

HOV lanes can become inefficient if they are too congested. Likewise, HOV lanes that aren’t full are not being used as effectively as possible. To ensure optimum efficiency, WSDOT is looking at conversion of HOV lanes to HOT lanes.

"HOT lanes" are high occupancy toll lanes. HOT lanes allow single occupant vehicles to drive in the HOV lane for a toll when there is room. Tolls are collected electronically with the use of a transponder. Toll price varies by congestion level; the less space, the higher the toll. In this way, the optimum number of vehicles is allowed in the lane.

The State’s first HOT lanes pilot project opened on SR 167 between Renton and Auburn in May 2008. For HOVs, use of the HOT lanes is very similar to use of the HOV lanes before the conversion. HOVs do not pay a toll on these lanes, nor do they need transponders. The main difference for HOVs is that access for all vehicles in and out of the lanes is now restricted to areas where the double-white line changes to dashed.

Some drivers may wish to use the HOT lanes as a carpool at some times, and as a single-occupant vehicle at others. These drivers will need to obtain a shield for their transponder. This will prevent automatic toll withdrawals from their account when there are two or more people in the car. Please see the on-line user guide for more information on SR 167 HOT lane operations.

More conversions of HOV to HOT lanes or express toll lanes are coming. These conversions may involve changing the minimum occupancy requirement for HOVs. For a list of planned projects by corridor, see the Moving Washington program.

How can I get more information?

Many questions can be answered by checking the HOV Common Questions page.