Only about half as many cars would use the Columbia River Crossing than previously predicted, and far more will choke the Interstate 205 bridge as drivers try to avoid paying tolls, according to new information uncovered by Portland economist Joe Cortright.

Interstate 5 at the CRC will cause Interstate 205 to reach capacity
previously not disclosed by the CRC to state legislators or the media,

(The green line in the chart below shows the previous projection they've been using to convince federal officials; the red line are the new numbers Cortright uncovered): 

The numbers echo a point that many critics have been making for years: that tolling I-5 while keeping I-205 toll-free is foolhardy, especially since driving overall is on the decline. (The Portland Mercury reported in 2010 that one independent expert called the plan "stupid.")

Cortright released his 12-page analysis (PDF) today, just hours before Gov. John Kitzhaber officially announced a Sept. 30 special session for Oregon lawmakers. The $2.8 billion Oregon-only CRC wasn't on the list of topics for the session, but WW has reported it could be squeezed in.

In the past, CRC officials have characterized the projected traffic on the new bridge by giving estimated annual counts of trips—estimated in the millions.

The way the project gave its tolling and traffic predictions meant the new study couldn't be compared with the CRC's Final Environmental Impact Statement, which gave its predictions in average daily trips, Cortright says.

But the records Cortright turned up provide the average number of daily trips—the way CRC officials had presented it to federal officials in seeking approval for the project.

For example, the new numbers he uncovered show the new tolled CRC would see about 78,400 daily trips—far fewer than the more than 160,000 cars earlier predicted.

Meanwhile, the newly disclosed numbers say the I-205 will carry two and a half times as predicted earlier.

"Nobody really thinks in terms of millions of transactions per year," he tells WW. "But if you say there are 138,000 cars a day using I-205, and we’re going to add 50,000—that paints a pretty clear picture in people’s minds."

Maxing out I-205 (which reaches its saturation point at 210,000 daily trips; a point CDM Smith predicts it will hit in 2023) will jam up traffic to Portland International Airport, which Cortright argues is even more economically important and time-sensitive than I-5.

He also points out that CDM Smith has still not explained how the project will make the $1.3 billion in toll revenue it needs with such high levels of diversion.

His guess? Higher tolls.