The 20 mph limit on most city of Aspen street may well increase the crash rates. It will not be complied with by the majority of drivers but will be by a few, maybe 10 percent. Speed variance will increase along with more frequent conflicts between faster and slower vehicles. The traffic flow will be less smooth overall. There may well be more, not less, cutting through neighborhoods because there will not be enough enforcement resources to cover every street.
Try it yourself on a quiet street when traffic is free flowing — it is extremely difficult to keep a modern car at 18-20 mph under good conditions when there are no traffic hazards present that would cause a safe driver to go that slowly where it was not necessary to do so for safety.
City engineer Trish Aragon is correct in a previous article (Aspen Times, March 20): “Aragon cautioned council members that speed-limit reductions don’t necessarily mean that drivers will slow down. She displayed a graphic under the title “Changing Speed Limit Does Not Change Behavior” to show that reductions or increases in limits often result in higher accident rates. The graphic was based on various studies.”
And I was one of several people who helped publicize the fact in Aspen that 14 or 18 mph limits are not permitted under federal and state laws. All limits are in 5 mph increments, nationwide. I am sure that Ms. Aragon knows posting a 14 or 18 mph limit would be in violation of the Manual of Uniform Traffic Control Devices which is mandatory for every state to follow.
Aspen residents may regret this move, except of course for the traffic court treasurer.