In the next few weeks, there will be a lot of public discussion of the proposal to spend $500 million to widen Interstate 5 at the Rose Quarter.
It's understandable that people are frustrated with congestion on area freeways, especially this one. But what's being proposed here, while its expensive, simply won't work, for four reasons.
First, more highway capacity generates more traffic — the phenomenon of induced demand is so well documented that it's now called "the fundamental law of traffic congestion." Added capacity encourages more people to drive, and in dense urban environments, there's plenty of "latent demand" that almost immediately fills added lanes as soon as they're built.
Houston widened its Katy Freeway to 23 lanes, and it's now even more congested and slower moving than before. Even PBOT and ODOT officials acknowledge that widening I-5 won't reduce daily traffic congestion.
Second, city and state engineers instead make a different claim: that more lanes and wider shoulders will be safer. But they don't actually have evidence for that. Instead, the claim is just based on engineering "rules of thumb."
Our actual experience on this freeway, with the same drivers, has been just the opposite. After ODOT widened I-5 between Lombard and Victory Boulevard in 2010, crashes went up, not down. It's not surprising — Metro's "State of Safety" report shows that wider roads tend to have higher crash rates. If crashes don't decline, ODOT can't claim to reduce traffic congestion.
Third, there's good evidence that funnelling more traffic onto the region's roads actually will cause congestion to get worse. After ODOT widened I-5 north of Lombard, and expanded ramps onto the freeway, traffic congestion became worse, as more cars were funneled even more rapidly into bottlenecks, causing the freeway to lose capacity. Consequently, the Interstate 5 bridge now carries about 10 percent fewer cars in the afternoon peak hour than it did 10 years ago.
Fourth, widening freeways runs directly counter to the need to take decisive action to deal with climate change. The evidence from last summer's smoky skies to the latest dire report from the International Panel on Climate Change shows we've put off action too long.
And in Oregon, the latest state report tells us we're losing ground in our stated objective to reduce greenhouse gas emissions, almost entirely because Oregonians are driving more. More freeway capacity will produce more driving.
ODOT is claiming that somehow by reducing congestion (which they won't do anyhow), that they'll reduce pollution and greenhouse gases associated with idling. That folk myth has been thoroughly debunked by the transportation experts at Portland State. Emissions from added car travel more than offset lower pollution for idling.
Widening freeways has never solved traffic congestion. It just leads to more driving, more sprawl and more automobile dependence. At a cost of $500 million for a little over two miles of roadway, and in the face of devastating climate change, this project shouldn't move forward.
A diverse coalition of community, neighborhood and environmental activists have joined together at nomorefreewayspdx.com. Visit our website to learn how you can submit comments on the public record to oppose this project before the April 1 deadline. We hope you'll join us.
Joe Cortright is a Portland economist, director of City Observatory, and a former nonresident Senior Fellow at the Brookings Institution and Chair of the Oregon Governor's Council of Economic Advisers.
City Observatory is an independent urban policy think tank based in Portland focusing on economic development, housing, transportation and poverty. You can view its research reports and commentaries on the I-5 Rose Quarter Improvement Proejct at cityobservatory.org/rose_quarter_congestion/