Modern Road Design in 5 Words: Cities Aren’t Hoses, They’re Gardens

Austin, Texas.

pfb logo 100x22Michael Andersen blogs for The Green Lane Project, a PeopleForBikes program that helps U.S. cities build better bike lanes to create low-stress streets.

Every bike lane believer has heard a variation on this concern: Won’t our cities grind to a halt if we redesign our streets to have fewer passing lanes for cars?

Last week, Minnesota writer Bill Lindeke offered a terrific response on his personal blog.

It was prompted to a letter from a person troubled by two of Minneapolis’s new protected bike lanes, which replaced passing lanes on 26th and 28th streets. The letter writer asked: won’t the traffic overflow, just as surely as a too-narrow pipe or hose will malfunction?

Lindeke’s reply is excellent. He begins with the story of a recent day when he turned on a hose for a friend watering a garden. At first he opened the valve all the way, but it was too much; his friend asked him to turn the flow down a bit so she wouldn’t damage the plants.

If our big goal as a city was to keep the most water flowing, then designing streets to maximize volume would be the obvious solution.

And in fact, that’s how traffic engineers have traditionally thought of traffic, as cars circulating like blood through corporeal arteries. Just like cholesterol clogging arteries, congestion was seen as inherent vice. A lot of money, public space, and social resources were spent on unclogging our streets to maximizing the “flow” of cars.

But the problem is that cities aren’t the hoses, they’re the gardens. Just like you don’t want to water your tomatoes with a firehose, you don’t want to maximize traffic flow in a neighborhood. We need to stop focusing on the water, and start focusing on the plants. How much water do they need to grow? At what rate? Are we flooding them?

In the analogy, the garden is the city. Neighborhoods, sidewalks, streets, and even dive bars with pulltabs require more than just a stream of cars passing by their doorstep. The require public spaces for socializing. They require people to be able to easily stop, park, and cross the street. They require access to ways of getting around that aren’t cars.

Now, the fact is that not every auto lane is actually useful at all. Very often, a three-lane street with a turn lane actually handles more traffic than a street with two lanes in each direction. Other projects simply make general travel lanes narrower, which makes people drive more carefully, which leads to fewer crashes and less congestion. That’s why Eighth Avenue in New York City saw average car travel times decrease after protected bike lanes went in.

But sometimes, it’s true that converting a passing lane to a protected bike lane would increase congestion. And Lindeke says that’s OK.

Lindeke’s argument is not that auto congestion is good. His argument is that the things that would reduce congestion — the things that would turn the hose of traffic up to full force — come at too great a price.

For cities to keep creating the economically valuable connections that they’re supposed to, they can’t prioritize vehicle speed and volume. Those can be fine goals in some cases, but not when they interfere with other things that cities need more.

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