Peak use shoulder lanes

Learn about special use roadway shoulder lanes, including when and how to use them.

Image of a conceptual shoulder lane control sign over a shoulder lane with supplemental side variable message sign and static sign.

Peak-use shoulder lanes are roadway shoulders designed and built to the same standard as regular travel lanes. They are available for use as a regular driving lane during specific days and times, providing an additional lane during periods of heavy congestion.

These special shoulder lanes are a new traffic management strategy being applied in specific areas as an alternative to slower, more expansive highway widening.

Careful consideration is given regarding where peak-use shoulder lanes are implemented. Not all locations are appropriate or available. Shoulders must have the width and construction to accommodate regular traffic, and the highway downstream must be able to handle the additional capacity.


There are two basic types of peak-use shoulder lanes used in the state:

  • Static: These lanes are open at specific times on specific days, as posted on the fixed signs.
  • Dynamic: These lanes are open on an as-needed basis, and use electronic signs to display when the shoulder lane is open to traffic. The electronic signs use the standard symbols of a green down arrow for when they are open, and a red X for when they are closed.

Truck climbing shoulders are not considered a type of peak-use shoulder lane, and are not addressed here.


Peak-use shoulders do not typically have many restrictions, and are usually open to all vehicles regardless of the number of occupants. Vehicles over 10,000 GVW are prohibited from using peak-use shoulder lanes, with the exception of buses. Some locations are posted as HOV-only shoulder lanes, and may be restricted to buses and carpools with a required minimum number of occupants.


In the event of an emergency or blocking vehicle while the shoulder lane is open, the incident is treated the same as if it were in a typical traffic lane and the shoulder is closed until the incident is cleared. Where electronic signs are available, they will indicate that the lane is closed with the red X symbol.


Interstate 405, Snohomish County

  • Northbound, from Highway 527 to Interstate 5
  • Dynamic, using electronic signs
  • Normally open during the afternoon weekday commute

Highway 2, Everett

  • Eastbound, from Interstate 5 to Highway 204 (Hewitt Ave Trestle)
  • Static, using fixed signs
  • Open from 2 PM to 7 PM, Monday - Friday

Highway 14, Vancouver (Future)

  • Westbound, from SE 164th Ave to Interstate 205
  • Dynamic, using electronic signs
  • Expected to be open during heavy westbound traffic - typically the morning weekday commute
  • Will also allow for separate exit lanes to northbound and southbound Interstate 205 for a greater distance
  • Project website

Traffic fatality crashes on Washington public roadways

increased 56% in March 2021 compared to March 2020.

11,906 incidents responded to

by WSDOT’s incident Response teams during the third quarter of 2021, nearly 6% more than same quarter in 2020.

WSF ridership was nearly 5.7 million in the first quarter of fiscal year 2022,

which was 1.6 million (38.3%) higher than the corresponding quarter in FY2021