Bus shoulder lanes

Bus using shoulder lane - Image courtesy Metro Transit in MN.

Bus shoulder lanes are authorized bus-only lanes that run along selected freeways. They are a low-cost solution that fully use the capacity of existing corridors and provide immediate benefits to fixed route buses operated by local transit agencies.

Most bus shoulder lanes are on the right shoulder, which allow buses to enter the freeway from the right-side during peak congestion hours and avoid having to  weave into either general purpose or HOV traffic.

In one instance in Snohomish County a bus shoulder lane will operate on the left shoulder next to the HOV lane. This allows specific buses to travel from one transit stop to another without having to weave in and out of traffic.

Bus shoulder lanes are not designed to carry a large amount of traffic and are only used during specific times so buses can maintain a reliable schedule during periods of peak congestion.

Current bus shoulder lanes
Currently in our state, we have bus shoulder lanes operating in Bothell and Vancouver. In Bothell, buses use the lanes that run along southbound I-405 from the SR 527 on-ramp to the NE 195th Street off-ramp and from the SR 522 on-ramp to the NE 160th Street off-ramp. In Vancouver, C-TRAN buses use shoulder lanes between I-205 and Southeast 164th Avenue.

Future bus shoulder lane locations
Beginning in the summer of 2018, WSDOT and Sound Transit will add a bus shoulder lane on the left side of southbound Interstate 5 between the Lynnwood Park & Ride transit stop and the Mountlake Terrace transit stop, about a 1.4 mile stretch. Community Transit and Sound Transit buses will be the primary users of this new lane.

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.

Who can use bus shoulder lanes?
Only licensed professional bus drivers on fixed routes can use bus shoulder lanes at low speeds in order to bypass heavy traffic. Transit-operated paratransit and vanpools or HOV vehicles are not allowed in the bus shoulder lanes. The following agencies are currently using the bus shoulder lanes:

  • C-TRAN
  • Community Transit
  • King County Metro Transit
  • Sound Transit

In addition, all drivers must be 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 also makes it easier for those vehicles to be seen by other motorists and allows drivers to sit high enough to see potential hazards within the shoulder.

How do bus shoulder lanes operate?
Bus shoulder lanes look and operate like any other shoulder and have a minimal effect on traffic in the general purpose or HOV lanes. The shoulder will still be available first for disabled vehicles, incident response and emergency or enforcement situations. The lanes are designed for adequate stopping sight distance with the reduced operating speeds.

Buses using the specified bus shoulder lanes cannot exceed all other traffic by more than 15 mph to ensure safe travel for all corridor users. The maximum speed allowed is 35 mph.

All bus drivers traveling in bus shoulder lanes have to yield to all other traffic, including any vehicles entering the shoulder and all motorists in the general purpose or HOV lanes when exiting the shoulder.

Signs alerting non-transit drivers of the potential for buses traveling along the shoulder during designated hours are posted along freeway corridors with bus shoulder lanes. Supplemental "Emergency Stopping Only" signs are located throughout the corridor.