Building on the success of the SR-14 bus on shoulder project, C-TRAN and partners WSDOT and ODOT added two new bus-only shoulder lanes in 2020: one on I-5 and one on I-205.
The I-5 project extends southbound from 99th Street to the Interstate Bridge, while the I-205 lane extends in both directions between SR-14 and Airport Way. The goal is to improve transit travel times by allowing C-TRAN buses to bypass traffic when the highway is backed up.
There are several limitations to when a bus is allowed to use the shoulder. The overall speed of traffic must be less than 35 mph, and the bus is only allowed to go up to 15 mph faster than other traffic, to a maximum speed of 35 mph. Priority for shoulder use is always given to emergency vehicles.
Both lanes, which were completed before the September trunnion replacement on the Interstate Bridge, were helpful in keeping buses on time during the project. The I-5 segment is considered a permanent addition; the I-205 lane is a one-year pilot project.
