In his capacity as the former head of the MSP’s Traffic Services Section it was Lt. Gary Megge’s job to eliminate speed traps set up by local municipalities. A few years ago Megge told the Detroit News, “I’ve spent eight years in traffic services, and I was a crash reconstructionist for five years before that, so I’ve seen my share of fatal wrecks, and I can tell you: Deaths are not caused by speeding. They’re caused by drinking, drugs and inattentiveness. The old adage that speed kills just isn’t realistic. The safest speed is the speed that is correct for that roadway at a given time. A lot of speed limits are set artificially low.”

The state police were one of the groups who backed, against the lobbying of municipalities, a change in Michigan law that required speed limits to be set based on actual traffic data and engineering studies. That law, Public Act 85 proposed to set limits based on what is known as the 85th percentile rule, a widely used measure that sets speed limits at how fast 85% of drivers travel safely. “It just doesn’t seem right to me that we would enforce a law where 90-98 percent of the people are in violation of it,” Lieutenant Megge told the DetNews in 2008. “It’s not the way we should do business in this country.”

After that law was passed, cities, towns and villages, through the Michigan Municipal League, pointed out that the law didn’t specifically require traffic studies and lobbied against revisions to Public Act 85 that would force them to due such studies. At the time, Megge agreed with them, to a point. “There is nothing in the code that specifically requires a municipality to conduct traffic studies,” said Megge, “but enforcement of any law must match the criteria of the law,” technically making invalid those tickets issued on roads whose speed limits were not compliant with P.A. 85. The cities opposed using such studies because they almost invariably call for higher speed limits, potentially reducing revenue from speeding tickets. The revisions eventually passed in 2010.

Since then, Lt. Megge’s job has been overseeing such compliance. Over his career he’s had a hand in the raising of over 400 speed limits across Michigan (though in a small number of cases the studies resulted in lower speed limits). By now there’s more than a decade’s worth of data from those raised speed limits and Megge insists that higher speed limits don’t mean that people drive significantly faster. They drive just as fast as they always did before, and just as safely. They just do so without risking points on their drivers’ licenses. The lieutenant says, “Over the years, I’ve done many follow up studies after we raise or lower a speed limit. Almost every time, the 85th percentile speed doesn’t change, or if it does, it’s by about 2 or 3 mph.”

In addition to the fact that they don’t really do anything to promote traffic safety, Lt. Megge says that unreasonably low speed limits actually make roads less safe by diverting resources away from the kind of law enforcement that has measurable effect. Megge recommends, instead of zealous speed enforcement against drivers who are effectively safe, focusing on drunk drivers, red light runners, drivers and passengers who don’t buckle up, and, an important point, enforcing realistic speed limits against the small minority of drivers who unreasonably and excessively speed.

Alex Mayyasi, at pricenomics.com, has an extensive look at how speeds limits have been and are being set, including an interview with Lt. Megge. As the good Prof. Reynolds says, read the whole thing, then come back here and share your views.

Ronnie Schreiber edits Cars In Depth, a realistic perspective on cars & car culture and the original 3D car site. If you found this post worthwhile, you can get a parallax view at Cars In Depth. If the 3D thing freaks you out, don’t worry, all the photo and video players in use at the site have mono options. Thanks for reading – RJS