For years, the Interstate 5 interchange on Wilsonville Road has been a mounting source of frustration for drivers. During rush hour, cars attempting to merge onto I-5 southbound stack on the onramp and spill out onto Wilsonville Road and back up Boones Ferry Road, causing traffic blockages for cross-town travelers. To help mitigate these blockages, the Wilsonville City Council approved an intergovernmental agreement (IGA) with the Oregon Department of Transportation (ODOT) Oct. 16 for the construction of a third stacking lane for the southbound onramp.
Last October, the City Council directed staff to explore traffic reduction projects. The staff focused on Wilsonville's most congested area: the Wilsonville and Boones Ferry roads intersection and the I-5 interchange. The projects — restriping Boones Ferry Road on the north side of Wilsonville Road, enlarging the Fred Meyer exit onto south Boones Ferry Road and the addition of a third southbound I-5 ramp — were to be done in stages.
The restriping project was completed June 2017, adding approximately 140 feet of left-hand stacking lane to Boones Ferry Road. The Fred Meyer to Boones Ferry Road exit, currently a single exit lane, will be joined by a second travel lane by narrowing the sidewalk. The improvement is estimated at nearly $160,000 and will go to bid in November.
But the major project will be the addition of a 1,400-foot ramp to I-5 southbound. Proposed to be located in the ODOT right of way, the project will cost the City an estimated $688,000. The design for the third lane has been completed and ODOT has given the green light.
A third light will be added to the onramp, but ODOT did not, however, increase the number of cars permitted to enter I-5 from the ramp, which is capped at 1,260 vehicle per hour.
Mayor Tim Knapp said that he regularly observes drivers bypassing the right stacking lane to access the I-5 southbound ramp by making an illegal right turn around the pedestrian median onto the ramp from the two travel lanes headed east on Wilsonville Road.
"The police department has been issuing some citations for that move, so we went back and looked at some of the signage there for a way to improve it to be clearer, perhaps, to the general public," said Nancy Kraushaar, community development director and City engineer. She added that City staff brought several options forward to ODOT to make it clear that the two, eastbound travel lanes on Wilsonville Road are strictly no-right-turn lanes; but ODOT had several qualms with the City's signage proposals and further study and discussion will be needed before any new signage is posted.
Because of the monetary investment needed to build the ramp, Knapp wanted some reassurance from the staff that it would be effective in reducing the infamous intersection congestion.
"We're trying to make a lot of small adjustments to make some sort of discernable effect," Knapp said. "So, my question is: For 700 grand on this ramp, are we going to have a discernible effect and what do we expect to see?"
"It will delay how long it will take for Wilsonville Road to get congested," Kraushaar said.
Eric Mende, Wilsonville capital projects engineering manager, added that the third ramp lane will take 40-50 cars off of Wilsonville Road, but that "when the Boone Bridge is backed up, it's just not going to do anything for us."
"It will back up later on Wilsonville Road and clear up sooner," Mende said. "But, again, the major cause on backups on Wilsonville Road is the Boone Bridge and the ramp meters."
The council and staff joked about someone removing the meters, citing how the traffic in town was anecdotally improved when the power to the meters went out a few months ago.
All joking aside, the ramp design is set to go to bid in November.