Bridge traffic didn’t grow with county

In a decade of growth in Clark County, a bedroom community where a third of the workforce commutes to Portland, you’d expect to see traffic on the bridges crossing the Columbia River to worsen.

It didn’t.

Traffic rose just 1 percent from 2002 to 2011, according to the most recent counts available, even as the county’s population grew 17 percent.

Critics of the Columbia River Crossing project have argued these figures cast doubt on traffic forecasts used to justify plans for a $3.5 billion new Interstate 5 bridge.

The project’s environmental impact statement estimates that, if no action is taken, 184,000 cars a day will cross the I-5 bridge in 2030. Planners say daily traffic congestion — which engineers define as freeway traffic that moves at less than 30 mph — will increase, from four to six hours a day on I-5 to 15 hours in both directions by then.

Yet over the past few years, drivers have taken their feet off gas pedals for a variety of reasons — high fuel prices, a poor economy and generational shifts.

Scott Bailey, a Washington state regional labor economist, agreed that the economy has dragged down driving.

“With the recession, there was a big drop in miles driven, with very little recovery there,” Bailey said. “Clearly, commuters were hit by job losses. Bridge traffic is not just commuters. It’s also shoppers, people visiting family, business trips and freight.”

Other forces

The economy isn’t the whole story, however. Traffic started to level off before the economy officially crashed in December 2007.

“The recession argument doesn’t wash. The decline in traffic on the I-5 bridge began well in advance of the recession, and traffic continued to decline even after the economy got better,” Cortright said. “The long-term trend has everything to do with the fact that gasoline cost in real dollars has doubled.”

The real price of gas declined from 1980 until 2000, and then started climbing, Cortright said.

“People respond to prices in a whole series of decisions: how much they drive, what kind of vehicles they drive, how far they travel, how far they look for jobs and houses,” Cortright said.

Since the economic downturn, those who remained employed weren’t likely to tinker with their jobs, Bailey said.

“I think with gas prices, most of the adjustment is going to be going toward a better-fuel-economy car. Jobs are a lot harder to come by. If anything, people would be willing to increase their commute to get a job,” Bailey said. “There was actually an increase in the number of Portland people commuting to Vancouver. That shows gas prices aren’t the big deal. It’s, ‘Where can I find a job?'”

Other factors also influence traffic flows on the I-5 bridge.

“Young people are driving less, and fewer are getting driver’s licenses — or waiting longer to get them. When you look at young adults, they are increasingly moving to city centers,” Cortright said.

And, on a more prosaic note, don’t forget orange cones.

The I-5 widening project at Delta Park in Oregon disrupted traffic flow from spring 2008 until its completion in 2010, Putney said.

Transit doesn’t seem to be a big factor in bridge traffic counts, however. Droves of drivers haven’t jumped out of their cars and onto buses.