Every experience I’ve had with speed cameras has been negative. That’s hardly a surprise, but the other common experience is that they always are set up in places where the speed limit is absurdly low (a 45-mph limit on a stretch of interstate highway in DC is a good example). As one might suspect, there is considerable evidence that greedy and corrupt governments use cameras as a revenue generator. But cameras are not a necessary component of speed traps. Here’s a story from Michigan about how local governments are ignoring state requirements to set reasonable speed limits solely because the bureaucrats want to rip off motorists:
Metro Detroit motorists who exceed posted speed limits may not be breaking the law, because in many cases the limits themselves are unlawful, according to one of the state’s top traffic cops. Four years after the passage of Public Act 85, which requires municipalities in Michigan to conduct studies to set proper speed limits, most cities, villages and townships have not complied, according to Lt. Gary Megge, head of the Michigan State Police Traffic Services Section. One likely reason, said Megge, whose section advises communities on how to set proper speed limits, is that communities want speeding ticket revenue, and failing to conduct the required speed studies allows them to keep enforcing their speed limits that Megge calls “artificially low.” …Ferndale Police Chief Michael Kitchen admitted revenue was the reason behind his recent decision to step up traffic enforcement. “We have to write more tickets in order to avoid layoffs,” Kitchen said. …Kitchen admitted that the 35-mph speed limit on the most heavily-driven roadway in Ferndale — Woodward Avenue near Nine Mile — is likely too low. “That speed limit would probably be 45 mph if they ever did a speed study,” said Kitchen, adding that Woodward falls under MDOT’s jurisdiction.
http://www.detnews.com/article/20100427/METRO05/4270380/1016/Many-speed-limits-set-too-low