Two new Bus on Shoulder C-TRAN corridors will soon give transit riders a faster commute on Interstate 5 and Interstate 205.

The change will allow buses to use the freeway shoulder to bypass traffic during times of heavy congestion. Buses will be authorized to use the shoulder of southbound I-5 between 99th Street and the Interstate Bridge in Vancouver, and on both directions of I-205 on the Glenn Jackson Bridge between State Route 14 in Vancouver and Airport Way in Portland.

Buses may only use the shoulder under certain conditions. The overall speed of traffic must be less than 35 mph. Transit vehicles are only allowed to go up to 15 mph faster than other traffic, to a maximum speed of 35 mph. And priority for shoulder use is always given to emergency vehicles, stalls, or breakdowns.

Both the I-5 and I-205 Bus on Shoulder corridors will be implemented in September, before a nine-day I-5 closure planned as part of the Interstate Bridge Trunnion Replacement Project. The trunnion project will close the entire northbound span of the Interstate Bridge from Sept. 12 to 20 and is expected to cause widespread traffic backups on Vancouver and Portland-area freeways and side streets.

Crews with the Washington State Department of Transportation and Oregon Department of Transportation have updated striping and signage in recent weeks along the designated Bus on Shoulder corridors. C-TRAN driver training is underway. Each corridor will function a little differently: Buses on I-5 will use the inside (left) shoulder, southbound only, while buses on I-205 will use the outside (right) shoulder in both directions.

The I-5 Bus on Shoulder lane will remain permanent after the completion of the trunnion project. The I-205 corridor will stay as a one-year pilot. Both are the result of continued partnerships among C-TRAN, WSDOT and ODOT in the region.

C-TRAN has used Bus on Shoulder lanes since they were first implemented in Clark County on a segment of SR 14 in 2017. The concept is commonly used elsewhere to create faster transit travel times and increased reliability. C-TRAN commuters have enjoyed similar benefits on SR 14.