Southbound I-5 - Bus on Shoulder

Project news

Project overview 

In summer 2020, WSDOT will construct a bus lane using the left shoulder of southbound I-5 between Northeast 99th Street and the I-5 Interstate Bridge in Vancouver.

Needs & benefits

Traffic backups and delays are a common occurrence for people who travel on southbound I-5 in Clark County. To provide more reliable travel times for transit users, C-TRAN and WSDOT are partnering to build a bus-only lane on southbound I-5 between the Northeast 99th Street Transit Center and the I-5 Interstate Bridge in Vancouver, for use during congestion.

How will it work?
Due to an increase in congestion on southbound I-5 during weekday, peak commute times, when travel speeds on southbound I-5 slow down to below 35 miles per hour, authorized transit buses will be able to use the left shoulder of southbound I-5, to bypass traffic delays. The bus on shoulder lane is not designed to carry a large amount of traffic and will only be used during peak commute times so buses can maintain a reliable transit schedule during periods of lots of congestion. Bus on shoulder lanes are a low-cost solution that fully uses the capacity of the existing highway to provide immediate travel time improvements for transit users.

How do bus shoulder lanes operate?
Regardless of whether the bus on shoulder lane is in operation or not, the bus on-shoulder lane will look and operate like any other shoulder and have a minimal effect on traffic. The shoulder will still be available for disabled vehicles, incident response and emergency or enforcement situations.

Does that mean I can drive on the shoulder?
Only licensed professional bus drivers on fixed routes can use the bus on shoulder lane at low speeds in order to bypass heavy traffic. All transit operators who use the bus on shoulder lane are specifically trained in the operating rules of bus shoulder lanes and able to handle complex driving decisions while in the shoulder. The large size of transit buses are easily visible to other motorists and allow the bus drivers to sit high enough to see potential hazards within the shoulder.

Bus shoulder lanes in other states
Washington is not the first state to utilize the shoulder for transit buses. In fact, the Minnesota Department of Transportation has been using them since the 1990s and has over 300 shoulder miles. Other states like Ohio, Illinois, California and Florida also have bus shoulder lanes.

What to expect during construction?
Travelers can expect nightly single and double lane closures on southbound I-5 between Northeast 99th Street and the Interstate Bridge, while crews pave and stripe sections of the Interstate to accommodate buses using the shoulder. Construction is scheduled during summer of 2020, and be complete before the end of the year.

Public involvement 

On Wednesday, Oct. 23, 2019, approximately 150 joined WSDOT, the city of Vancouver, C-TRAN and the Port of Vancouver at an open house to learn about this project.


  • Spring 2020: Project scheduled to be advertised for competitive bidding 
  • Summer 2020: Construction scheduled to being
  • Late summer 2020: Project scheduled for completion


The estimated cost of the project is $6.125 million and is funded by a C-TRAN grant.


Susan Fell
WSDOT Clark County Engineering Office

Christine Selk  
CTRAN Communication and Public Affairs Manager

Celeste Dimichina​
WSDOT Communications

Southbound Interstate 5 - Bus on Shoulder Project Location Map

Southbound Interstate 5 - Bus on Shoulder - project overview graphic