HOV Lane Rules in Washington State: Hours, Tolls, and Fines

HOV lane rules in Washington state require most vehicles to carry at least two people before entering a carpool lane, with certain express toll corridors raising that to three during weekday rush hours. The rule applies from the moment you enter the lane until you leave it, and a first violation costs $186 after court assessments.

Who Counts Toward the Occupancy Requirement

Washington’s Department of Transportation sets the occupancy level for each HOV corridor, and the required number is posted on signs at the lane entrance.¹ Most highways use a “2+” standard: the driver plus at least one passenger. Some corridors bump that to “3+” during peak commute windows. The posted sign always controls.

Every living person in the vehicle counts, regardless of age. An infant in a car seat satisfies the second-occupant requirement just as well as an adult. Pets do not count. Neither do mannequins, dolls, or any other prop placed in a seat to fake a passenger, and Washington treats that stunt as its own separate offense.

Federal law sets a floor here. No state may require more than two occupants as the baseline minimum on a federally funded HOV facility, though states can raise the threshold above two on specific corridors.²

Vehicles That Qualify Regardless of Passenger Count

Several vehicle types get HOV access even with a solo driver:¹

Motorcycles. Federal statute requires states to allow motorcycle access unless the state certifies a safety hazard and the U.S. Secretary of Transportation accepts that certification. Washington has not sought that exemption.³
Rubber-tired municipal transit buses.
Any bus seating 16 or more, which covers full-size transit coaches and most school buses.
Marked emergency and law enforcement vehicles operated by on-duty personnel.
Vehicles transporting time-urgent organs or tissue donors.⁴
Private transportation providers with an eight-or-more-passenger capacity, including auto transportation companies, passenger charter carriers (excluding stretch limousines), nonprofit transportation providers, and private employer shuttles, as long as their use does not interfere with public transit operations.⁴

Vehicles That Cannot Use HOV Lanes

Trucks over 10,000 pounds gross vehicle weight are barred from HOV lanes no matter how many people are inside.¹ The same limit applies to any vehicle-and-trailer combination that pushes past 10,000 pounds. The one exception: a tow truck over that weight may use the HOV lane when responding to an emergency on that specific roadway.

Unlike some states, Washington does not give solo drivers of electric, plug-in hybrid, or other low-emission vehicles a free pass. Clean-energy vehicles must meet the same occupancy requirement as everyone else. Federal law would allow such an exemption, but Washington has not adopted one.²

When the Restrictions Apply

HOV lanes are marked by a white diamond symbol painted on the pavement at regular intervals, paired with roadside signs showing the occupancy requirement and the hours it applies. Standard HOV lanes on routes like I-5 and SR 16 stay restricted around the clock. Washington does not open these lanes to general traffic during off-peak hours the way some other states do.

The express toll lanes on I-405 and SR 167 work differently. Those lanes go free and open to all traffic after 8 p.m. and on weekends.⁵ Overhead electronic signs can also modify the rules during construction or incidents, so read them before merging.

Express Toll Lanes on I-405 and SR 167

The express toll lanes layer tolling on top of the usual HOV rules. Solo drivers can pay their way in through a variable toll that adjusts in real time with traffic volume, ranging from $1 to $15 on I-405.⁶ Using these lanes requires a Good To Go! account; drivers without one receive a Pay By Mail bill at a higher rate.

Carpoolers who meet the occupancy requirement can ride toll-free, but only if they carry a Good To Go! Flex Pass set to HOV mode. Having enough people in the car does not exempt you on its own. The pass tells the overhead tolling sensors that your vehicle qualifies.⁷ If the pass is missing or set to the wrong mode, you will be charged the full toll automatically.

Occupancy requirements on I-405 shift throughout the weekday:⁵

5 a.m. to 9 a.m.: 3 or more people per vehicle
9 a.m. to 3 p.m.: 2 or more people per vehicle
3 p.m. to 8 p.m.: 3 or more people per vehicle
After 8 p.m. and weekends: open to all traffic, no carpool or pass needed

This is where drivers most often get tripped up. Two passengers are enough at noon, but the same carpool becomes a violation at 3:01 p.m. when the threshold jumps to three. The time boundaries are strict.

As of October 2025, SR 167’s express toll lanes were updated to match the I-405 system. Carpoolers need a Flex Pass set to HOV mode to travel toll-free, and motorcyclists need a separate Motorcycle Pass to avoid tolls. New designated access points are marked by dashed white lines, and double white lines on SR 167 are now illegal to cross.⁸

Crossing In and Out of the Lane

On the express toll corridors, you can only enter or exit at designated access points marked with dashed white lines. Double white lines mean the boundary is sealed, and crossing them is a traffic violation on its own. Standard HOV lanes on other highways use a solid or dashed white line at the boundary, with signage indicating where entry is allowed. Cutting across a solid double white line to duck into or out of an HOV lane is one of the most common mistakes drivers make, and troopers watch for it.

Fines and Penalties

Washington treats HOV lane violations as traffic infractions with escalating fines. The base fine set by statute is “not less than” $125, and with standard court assessments a first ticket totals $186.⁹ A second or later violation within two years carries a statutory minimum of $175, which comes to $336 after assessments.⁴

Using a mannequin, doll, or other prop to fake a passenger adds a separate $200 penalty on top of the base fine.⁴ A first-time deception violation therefore runs at least $386.

The Washington State Patrol handles enforcement, running targeted patrols along HOV corridors.⁹ On the express toll lanes, the overhead sensors add a second layer: they will charge your account or issue a Pay By Mail invoice if your Flex Pass is not set to HOV mode, whether or not a trooper stops you.

1
Washington State Legislature. Washington Administrative Code 468-510 – Lane Use Restrictions
2
Office of the Law Revision Counsel. 23 USC 166 – HOV Facilities
3
Federal Highway Administration. Federal-Aid Highway Program Guidance on High Occupancy Vehicle (HOV) Facilities
4
Washington State Legislature. RCW 46.61.165 – High Occupancy Vehicle Lanes
5
Washington State Department of Transportation. I-405 Express Toll Lanes
6
Good To Go! I-405 Express Toll Lanes
7
Washington State Department of Transportation. HOV Lanes
8
GovDelivery. SR 167 Express Toll Lane Changes Coming Oct. 20
9
Washington State Department of Transportation. HOV Policy