Articles by Clark Williams-Derry

Is there another side to Seattle’s good news?

This is excellent news:

Seattle is one of the first major U.S. cities to claim it has cut greenhouse-gas emissions enough to meet the targets of the international Kyoto treaty aimed at combating global warming.

The achievement, at a time when the city has enjoyed a boom in population and jobs, sets Seattle apart both from the nation as a whole and other cities that have seen greenhouse gases soar in recent years.

Well, good on Seattle. But at risk of sounding like a stick in the mud, there's still a question mark in my mind about how much progress the city's really made.

Commuters in Seattle avoid congested roads by driving less

Apparently, folks in Greater Seattle are responding to congestion by ... driving less! Which is, quite literally, no surprise at all. A comprehensive study of transportation patterns in cities across the globe found that high levels of congestion are linked with low overall energy consumption. When roads get congested, people adjust, and find alternatives to long, time-consuming commutes.

And that's what seems to be happening in Seattle. Highway congestion has grown in the region, as it has virtually everywhere in the U.S. But per-capita car ownership is on the decline, and total vehicle miles per capita has begun to level off. More importantly, the article cites evidence that growth management laws have concentrated much of the region's recent growth into already-urbanized areas -- the sorts of places where people don't have to make long treks to jobs or stores.

Is the cure worse than the disease?

The ever-geekalicious Todd Litman of the Victoria Transport Policy Institute had a great take on traffic congestion a few weeks back on Planetizen.

As Litman explains, most congestion studies (such as this annual study, which always gets a lot of press) consistently overestimate the costs of congestion. But even using these relatively high estimates, the costs of congestion are pretty modest, compared with the comprehensive costs of owning and operating a car.

In fact, a quick scan of Litman's data suggests that congestion represents less than 5 percent of the total cost of car transportation.

Widening roads does not, in fact, reduce emissions

Why is it that stupid ideas get all the air time?

For months, fellow climate geeks have been telling me that road-builders -- and the politicians who love them -- have started to make a startling claim: namely, that widening a congested highway will help curb global warming. By reducing stop-and-go traffic, the argument goes, cars will operate more efficiently and waste less fuel. So if you want to save the climate, you'd better widen that road!

To me, this sounded too dopey to be worth refuting. I mean, sure, over the short term, congestion relief might help a bit. But what about all of the emissions from road building itself -- and, more importantly, from the extra traffic that will inevitably fill those new lanes?

But despite its obvious absurdity (or perhaps because of it) this particular suburban legend seems to be getting a life of its own. Just take a look at what British Columbia's Premier had to say recently about a proposed highway widening project in greater Vancouver, BC:

Campbell ... continued to defend the [highway] project ... saying that it will reduce emissions and make room for rapid-bus services along the highway.

Because I couldn't find anything addressing this issue online (academics have better things to do with their time, apparently), I spent a bit of time running some numbers. You can read the full report here (PDF) if you're a real geek. But in a nutshell: congestion relief may offer some slim GHG benefits over the short term; but these benefits are absolutely dwarfed by the emissions from road construction and, more importantly, by all the extra traffic that fills the expanded roadway.

In fact, it looks to me as if adding a single lane-mile to a congested urban highway will boost CO2 emissions by at least 100,000 tons over 50 years. And that's making some pretty optimistic assumptions about fuel economy improvements.

So now, if anyone out there in Grist-world hears this particular suburban legend, you'll have some numbers you can use to smack it down.