Friday, August 17, 2007

Why stop?

I've argued against stop signs as traffic calming from what I'll call the random-compliance angle. If you put up stop signs where there is no right-of-way conflict to manage:

  • Pedestrians will rely on the stop signs and expect that traffic will stop.
  • Some motorists will recognize the stop signs as unnecessary and will not stop.

The combination of reliance by one party and non-compliance by another party has the potential for injury or worse.

But, there's another angle. Let's call it the excess-compliance angle.

The purpose of traffic calming is to slow traffic, not stop it. (This is not the case on our busier streets and intersections.) Sufficiently slowed traffic has time to stop for pedestrians. Pedestrians have enough time to react to traffic. Motorists are better able to stop for crosswalks, making crosswalks more useful for pedestrians. Slowing traffic reduces the severity of injury and the risk of death.

Our neighborhoods don't need to stop traffic flow to enjoy these benefits. Pedestrian traffic, while it should be a priority, is rarely as heavy as car traffic. (Not that we wouldn't like it to be!) Outside of school time, crosswalk crossings are especially infrequent.

It's unreasonable to bring every car to a full stop just so we can make conditions ideal for those occasions when there is a pedestrian.

The point of traffic calming is to balance traffic flow with pedestrian safety, convenience, and comfort. Appropriate traffic calming measures allow traffic to flow at a reasonable pace ... except when there is a pedestrian in a crosswalk. Stop signs stop the flow of traffic all the time, regardless of actual need to stop.

Which brings us back to the random-compliance problem. Non-compliance stems from the motorist's intuitive—and correct—understanding that a stop-sign is not needed to resolve a right-of-way conflict and that it is overkill to address pedestrian issues.

Why stop traffic when you don't have to?


Left Out Arizona said...

I agree that stop signs may do too much, but will speed bumps work. Moreover, the idea that people completely ignore stopsigns ("random compliance") is a bit of a stretch. Most "violators" simply roll the stop --which may be better from a pure "traffic calming" point of view.

Anonymous said...

We just moved from Ann Arbor to Newton, and my kids are having a lot of trouble negotiating the "no stop sign" cross-walks. They've been taught to cross at a stop sign and to wait for the on-coming traffic to come to a complete stop.
From what we've seen in Newton, although drivers are supposed to yield to pedestrians in the cross-walk, this only seems to happen if you're already directly in the path of the car. This is not how I'd like to have my children getting across the street.