There’s been a bit of controversy of late about the the proposal to add lanes to the I-5 bridge that connects Portland with Vancouver, WA.
Some folks think a wider Columbia River Crossing is a great idea, since they think it’ll ease rush-hour congestion. Others are opposed, arguing that a wider road would a) funnel more cars into Portland, b) fuel sprawl in suburban Clark County, and c) ultimately be self-defeating, since the extra lanes and extra sprawl will soon attract more drivers, who’ll clog the new highway despite the extra lanes.
Unsurprisingly, most bridge boosters have dismissed the naysayers’ concerns. Washington’s and Oregon’s growth management systems, they claim, will eliminate the specter of sprawl; and tolls on the bridge will prevent the reemergence of congestion.
In today’s issue of The Oregonian, Portland Metro Council president David Bragdon says some exceptionally smart things about the controversy. In a nutshell, Bragdon thinks that the boosters (including the state departments of transportation) simply aren’t taking concerns about new traffic seriously enough:
The way in which these projects have a history of defeating their purpose is when they attract more traffic than expected and create more congestion, rather than solving it. I am well aware the modelers claim that won’t happen in this case, but you need to look at the model and the modelers before accepting that assertion.
Bragdon clearly understands the most salient fact: new road capacity on a crowded urban highway almost always spurs the growth of traffic. And he thinks the state departments of transportation haven’t done a good job of explaining why the “if you build it, they will come” phenomenon doesn’t apply to the Columbia River Crossing:
When the two state DOTs (really the highway divisions) are asked about induced demand, they cite the mitigating factors above, which are valid, but they ultimately rest their case on two key statements that are unproven—and that the two DOTs will not allow to be scrutinized independently.
Interestingly, Bragdon is generally supportive of a new I-5 bridge. He just wants it done right, and honestly. To me, that shows a thoughtful and nuanced take on the issues: being supportive of a highway project doesn’t mean that you have to be blind to empircal evidence about what wider roads can do to traffic volumes.
Bridge photo courtesy of Flickr user Devlyn under a Creative Commons license.
Wells
I attended Thursday’s public hearing and gave my 2-cents and 3 minutes worth. Most testimony favored the 12-lane bridge. I tried to present the idea that there was a safety line crossed at 12-lanes. Basicly, all new bridge options have 3 thru-lanes and 1,2 or 3 ‘entrance/exit’ lanes, formally called ‘add-drop’ lanes or ‘auxilliary’ lanes. One of the entrance/exit lanes (my preference) goes the entire length of the project, from North Portland to SR500. This is called the ‘4th lane’ though it acts as an entrance/exit lane. I believe the 4th lane is important for safety and efficiency. It should be retained, but is only offered on the 12-lane option. It looks like the 10-lane option could offer the 4th lane, in which case, there would be one additional entrance/exit lane instead of two. The 2nd additional entrance/exit lane (12-lane option) is only between Hayden Island and SR14, and between Mill Plain and SR500. Here is my question about safety: The 4th lane creates a buffer between the 3 thru-lanes and entrance/exit lanes. Truckers need this lane to manage accelleration and decelleration. Where the extra entrance/exit lanes are, some motorists will subconsciously view the extra width as an excuse to accellerate, thus creating a safety hazard on the bridge, the worst place. The environmental impact of the extra lane between Mill Plain and SR500 will be harsh, and there too the extra lane will encourage speeding in an area where merging occurs. The agencies conclude the 12th lane is safer, but I disagree. I woudn’t mind being proved wrong, but I’m sure the die is cast and no one is going to give it any thought, certainly not the crew at Daily Score. Dare ya.
Wells
Dirty dog double dare ya, wussies!
Charm
What’s wrong with building a full 12 lane option and striping for less? Isn’t it important to build for any potential capacity needs? Wouldn’t it be more expensive to rebuild the bridge in 20 years because capacity is too limited? I have wondered the same thing about the 520 floating bridge and Hwy 99 here in Seattle. Why not over build and under stripe? Have the capacity if needed, but limit it a little. Ease traffic, but not enough to leave the freeway flowing at the speed limit 24/7?Thoughts?