New ‘Bus on Shoulder’ pilot aims to reduce congestion

The pilot launched Nov. 1

SMART Bus driving on the right shoulder of I-5 during a training exercise between I-205 and Elligsen Road in Wilsonville.
Bus on Shoulder allows authorized buses to use the highway shoulder when traffic drops below 35 miles per hour.

It’s OK: the bus traveling on that shoulder is allowed to be there!

On Nov. 1, the Oregon Department of Transportation launched its latest Bus on Shoulder pilot project, aimed at reducing congestion and improving transit reliability on Interstate 5 between Wilsonville and Tualatin. The pilot corridor runs about 2 miles on the interstate between I-205 and Elligsen Road.

In the one-year pilot, South Metro Area Regional Transit (SMART) buses may use segments of I-5’s shoulder both northbound and southbound when traffic drops below 35 mph.

Last year, ODOT partnered with the Washington Department of Transportation and C-TRAN (Clark County’s transit provider) to implement a similar pilot project. That one ran on I-205 between Oregon and Washington across the Glenn Jackson Bridge. The project took place during the September 2020 closure of the northbound span of the Interstate Bridge for the trunnion replacement.

Bus on Shoulder pilot projects are included in ODOT’s Strategic Action Plan as important elements in helping reduce congestion in the Portland area. They are being coordinated by the Urban Mobility Office as part of the Comprehensive Congestion Management and Mobility Plan.

Ready to start the training
Photos on our Flickr Album

How it works

SMART buses may use the I-5 shoulder when the traffic drops below 35 mph, and:

  • Buses may then travel up to 15 mph faster than the mainline of I-5 traffic, but no faster than 35 mph.
  • Buses must merge back into travel lanes at least 1,000 feet before the end of the shoulder.
  • Cars, trucks and all other non-emergency vehicles must remain on the highway travel lanes and stay off the shoulder except to avoid debris or for emergencies.
  • Emergency vehicles, maintenance vehicles and disabled vehicles take priority on the shoulder.
  • Bicycles on the shoulder have priority over buses. Transit vehicles are required to merge back into the travel lanes when encountering a bicycle.

New highway signs, pavement striping and roadway legends will be installed to inform motorists of the appropriate shoulder uses. SMART is the only transit provider authorized to use the shoulder in this pilot project. SMART bus line 2X operates on I-5, running north and south between the Wilsonville Transit center and the Tualatin Park and Ride

A proven strategy

In other states, Bus on Shoulder projects have been effective in getting transit vehicles through congestion quickly and safety, creating a more efficient traffic flow and a more reliable commute. Bus on Shoulder is widely considered a multimodal, low-cost alternative to expanding roadways or dedicating lanes for high occupancy vehicles.

The team will closely monitor the pilot’s performance. If they find it effective and safe, ODOT could consider expanding the concept, making it permanent in places and allowing other transit agencies to join in.

To learn more, visit the Bus on Shoulder website.

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