Monday, March 2, 2009

Stop sign studies

Stop signs are not for slowing traffic. That's what the Manual Of Uniform Traffic Control Devices says. And, there are studies to back up the policy.

This review surveys over 70 technical papers on the use of stop signs to slow traffic and concludes, no surprise here, that stop signs are ineffective if the aim is slower cars.

  • Twenty-two papers found that multi-way stops do not control speeds.
  • Nineteen studies found that compliance is poor at unwarranted stops.
  • Thirteen studies found that unwarranted stop signs decrease pedestrian safety.
And, on and on.

Some more (possibly) counterintuitive findings:
  • Unwarranted stop signs create more noise in the vicinity of the intersection
  • Unwarranted multi-way stop signs create increase operating costs
Stop signs do make neighbors feel safer, though the evidence contradicts those feelings.

The city of Northampton has a good FAQ on stop signs.

1 comment:

Wilmer Geraci said...

Whoa, these findings are surprising, Sean. Who knew that those simple-looking stop signs had that kind of complex impact on motorists? I hope that those studies would help create the perfect criteria for deciding whether or not a corner or intersection warrants a stop sign. Maybe that would also decrease the incidence of stolen signs.