Traffic Controls and Unintended Consequences

There’s been a lot of emphasis put on distracted driving recently and most of it is a PC thing. More laws don’t necessarily mean more safety and speed laws have be a topic here to illustrate that. A PhysOrg report by Michelle Wheeler on a study that Strictly enforcing the speed limit may make drivers worse┬áthat brings these two driving problems together.

A UWA study found strict enforcement of the speed limit could be bad for road safety by making drivers focus on their speed rather than hazards.

It found people who drove under the stricter conditions were less likely to spot red dots that appeared in their peripheral vision. They also reported a higher mental workload.

Lead researcher, Dr Vanessa Bowden, says … “We came to the conclusion that [monitoring speed] is eating up their limited pool of visual and mental resources a little bit and taking their attention perhaps a bit away from the task of safe driving.”

“It’s what we want to do next with this, is see if it actually translates into more accidents,” Vanessa says.

This is reflected in the MUTCD (manual of uniform traffic control devices) published by the U.S. DOT. It says “When a speed limit within a speed zone is posted, it should be within 5 mph of the 85th-percentile speed of free-flowing traffic.” [guidance # 11]. Implicit here is that most drivers drive at a safe speed and they should not be subject to traffic restrictions that will distract them from the primary responsibility to drive safely.

In the section on Engineering Speed Limits, there is another item of note.

In terms of traffic law, speed limits should reflect the maximum reasonable and safe speed for normal conditions. That is speed limits should be acceptable as reasonable by most drivers and separate high and low risk speed behavior.

This acknowledges a social aspect of law. Those subject to the law must see it as ‘reasonable’ and with a proper purpose else they lose respect for the law and its enforcement. Speed enforcement often violates these concepts and the distracted driving laws are following suit. This is not good for either safety nor for law enforcement. Putting up a new law is easy. Finding a solution to poor driving habits and judgments is difficult. Conflict between law and good driving are destructive. Better solutions need to be found.

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