The regional economy’s post-recession growth has led to more congestion and longer delays for southbound drives into Portland, according to initial data gathered by the Southwest Washington Regional Transportation Council staff.
“You’ve got to consider, 2010 and 2011 were probably some of the best traffic years we’ve experienced, in many years, due to the recession,” Dale Robins, senior transportation planner with RTC, told the board of directors Tuesday night. Now, the transportation situation “is much worse than where we were five years ago.”
RTC staff found that the region’s transportation system is seeing more commuter trips, and those are causing more delays on the area’s already most congested corridors.
For 2015, RTC staff gathered data by looking at southbound peak traffic times, Monday through Friday, 5 a.m. to 11 a.m.
“The situation on (Interstate) 5 has gotten to the point where doing nothing is probably not an option,” Robins said.
Traffic data from RTC show that over the past five years, travel time rose 291 percent in the morning commute from state Highway 500 to Jantzen Beach on I-5. Travel time for that stretch of commute grew from 6 1/2 minutes to about 25 minutes.
A memo on the data from RTC staff says the increase in delays and congestion is worst in the morning and evening commutes, as people try to cross the Interstate 5 and 205 bridges between Washington and Oregon. According to RTC staff, an average of more than 294,000 vehicles crossed the I-5 and I-205 bridges each day in 2015, compared with 273,000 in 2011.
‘Liquid in a funnel’
The peak traffic period on the Interstate 5 Bridge is between 7 a.m. and 9 a.m., but RTC staff say commuters are leaving earlier to arrive at their destinations on time, and that’s lengthening the peak traffic period.
“The corridor starts to fail at 7 o’clock, so now people are moving to the 6 o’clock hour,” Robins said. “It’s like pouring liquid in a funnel; if you pour it too fast, it just backs up. That’s kind of what’s happening across the I-5 Bridge.”
The number of drivers crossing the I-5 bridge between 7 and 9 a.m. decreased by 1,000 between 2011 and 2015. However, the number of drivers crossing it between 5 and 11 a.m. increased by 500 during that time.
Also, C-Tran’s travel time from the 99th Street park-and-ride to downtown Portland increased 19 minutes over five years, up from 33 1/2 minutes in 2011 to 52 1/2 minutes in 2015.
The report was prepared for the 2015 congestion management monitoring process, which is a federal planning requirement for metropolitan planning organizations with populations greater than 200,000. The monitoring process provides data and analysis for effective management of the regional transportation system.
Robins said the region should consider a study to evaluate a number of low-cost management strategies to figure out how to move traffic better. As examples, he listed transit, carpooling and metered onramps as short-term solutions to reduce bottle-necking.
Republican Clark County Councilor Julie Olson, a member of the RTC board, questioned why the study didn’t include weekends.
Board member and Republican Clark County Councilor Jeanne Stewart said those and “just about every other short-term solution” is already being used; the real issue is infrastructure.
“This is a volume and capacity problem,” she said. “However dreaded it is to bring it up in any meeting, a third crossing is imperative. … We need a team of people to sit down and start talking about another bridge.”
Port of Vancouver Commissioner and board member Jerry Oliver echoed her comment.
Fellow board member and Vancouver City Councilor Jack Burkman recommended the board should have a discussion at the June 7 meeting, not only about a third bridge, but a road system to support it.
“A bridge by itself is not a solution,” Burkman said.
