Reality: Freeways Cause Traffic

The old-fashioned street grid is the best way to circulate auto, bicycle, and pedestrian traffic.

This makes sense to anyone who spends time in both grid-network areas as well as freeway/artery areas, and has begun to be accepted by more forward-thinking planners.

Now from no less reputable a source than Scientific American comes this article showing experimental and empirical evidence directly supporting this idea as well.

But in the 21st century, economic and environmental problems are bringing new scrutiny to the idea that limiting spaces for cars may move more people more efficiently.

As documented in Seoul, Boston and Montgomery, Alabama, the idea is that [gasp] wide arterial roads induce demand, which causes gridlock. Removing those expressways causes traffic to move more smoothly than it did before.

In the Boston example, Gastner’s team found that six possible road closures, including parts of Charles and Main streets, would reduce the delay under the selfish-driving scenario.

The article also documents positive results from conversion of divided rights of way to the "shared street" concept, or woonerf. In a woonerf, all modes of transportation are allowed on any part of the road, and traffic signals and lane markers are absent.

The idea is that the absence of traffic regulation forces drivers to take more responsibility for their actions. “The more uncomfortable the driver feels, the more he is forced to make eye contact on the street with pedestrians, other drivers and to intuitively go slower,” explains Chris Conway, a city engineer with Montgomery, Ala.

And finally, author Linda Baker gives props to SF for our parking maximums:

In San Francisco, for example, developers must restrict parking to a maximum of 7 percent of a building’s square footage, a negligible amount. Although downtown employment has increased, traffic congestion is actually declining, [Patrick] Seigard says. With fewer free spaces to park, drivers seem to be switching modes, relying more on mass transit, cycling and just plain walking.

Imagine that.