The regional economy is going strong and the cities of Southwest Washington and Northwest Oregon are growing, but all that activity is making the work commute in Clark County a nightmare.
Data collected last year by the Southwest Washington Regional Transportation Council show delays between Vancouver and Portland have increased, travel times on major arterials are less reliable, major arterial congestion is getting worse and so are delays at major intersections.
Driving conditions are the worst during the peak morning and evening commute periods.
The initial findings were presented to the RTC board of directors during their regular Tuesday night meeting.
Between 6 and 8 a.m., speeds dropped between 55 percent and 71 percent between 2011 and 2016 on Interstate 5 between Northeast Highway 99/Main Street down to Jantzen Beach; on Interstate 205 from state Highway 500 and Airport Way in Portland; and on state Highway 14 between Southeast 192nd Avenue and I-205.
“The good news is the I-5 corridor did not get any worse between 2015 and 2016,” RTC senior transportation planner Dale Robins told the board. During the morning commute last year, traffic moved through the corridor at about 9 mph.
“You can’t get too much slower than that, I don’t think,” he said.
Also between 2015 and 2016, travel speeds during the peak morning commute on I-205 slowed from 48 mph to 25 mph.
From 2011 and 2016, the number of crossings on the I-205 and Interstate 5 bridges went up by more than of 24,000 per day, but fewer cars are actually getting across during the morning and evening peak hours because of the increased congestion.
“This is similar to pouring water through a funnel, if you pour too much water all at once it’s going to back up and overflow on you,” Robins said. “What we’re doing is we’re putting too many cars across the bridges at one time.”
The congestion also affects C-Tran’s travel time during its commuter service into Portland. In an interview with The Columbian, C-Tran spokeswoman Christine Selk said buses traveling from Fisher’s Landing Transit Center during the peak morning period are supposed to reach downtown Portland in 26 minutes, but the actual average travel time is just under 40 minutes.
“We are constantly talking about commuter service and the challenges that we are up against when it comes to travel times into and out of Portland,” she said.
The data also show people leave earlier and later to avoid the worst congestion, but that makes the peak traffic periods last longer than before.
Also, as traffic slows on the highways the traffic delays begin to slow traffic at some intersections of major arterials, such as Fourth Plain and Andresen Road, Fourth Plain and Highway 500 and Highway 500 and Falk Road.
The data are compiled as part of an annual congestion monitoring report called the Congestion Management Process. The document provides data to local agencies to they can in turn develop strategies to address the issues.
At the next RTC meeting, staff will present information on traffic in Northwest Oregon. RTC staff will also present more specific data about where the bottlenecks are occurring throughout the corridors.