The Blog

The Safety Myth

Photo-radar cameras are designed to catch speeders and save lives. Only, there's not much evidence that the speed limit is any safer. Part 3 in a series.

11:00 PM, Apr 2, 2002 • By MATT LABASH
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Even if it's not much of a beach read, "Traffic Safety Facts" tells a fascinating tale not often told by these same people--namely, the truth. While safety Cassandras love to say that accidents increased from 1992 to 1996, they conveniently select those years as bookends since 1992 was an aberrantly low-accident year, and in 1996 accidents were nearly as high as they've ever been. But when considering the fatality rate per 100 million vehicle miles traveled, that number has declined or held steady every year since 1977. And since 1988, injury rates per 100 million vehicle miles traveled have declined or held steady every year except two (in 1994 and 1995).

Both fatality and injury rates are at an all-time low, with a mere 1.5 and 120 per 100 million vehicle miles traveled, respectively. If there was ever a safer time to drive a car than 1999, it was probably 2000--though those statistics are not yet processed. No matter, says the camera enforcement crowd--speeders and red-light runners are causing the bulk of havoc on our roads.

Except that they're not. According to NHTSA, 38 percent of all fatal crashes involve alcohol, and drunk drivers should logically be the most enthusiastic boosters of camera enforcement--since a red-light-camera-monitored intersection ensures no cops will be present. From the drunk's point of view, a red-light citation in the mail beats a DWI arrest. NHTSA's data show that only 21 percent of drivers involved in fatal crashes had racked up speeding convictions within 3 years of the date of their crash, while 57.3 percent had no driving convictions over the same period. This appears to buttress photo radar opponents' argument that speeding doesn't kill people, bad driving does.

Among the "Related Factors for Drivers Involved in Fatal Crashes," speeding and red-light running aren't even the league leaders. NHTSA records factors in such a way that more than one can be listed for any given driver, meaning that the categories listed add up to 146.9 percent of all factors, instead of 100 percent. But after considering that 36.5 percent of drivers had no factors reported, or that NHTSA's "Related Factors" table doesn't account for drunk drivers (NHTSA says elsewhere that 38 percent of fatal crashes are "alcohol related") "failure to keep in proper lane or running off the road" is by far the most frequent related factor for drivers involved in fatal crashes.

Speeding ranks a distant second at 19.7 percent. Though that figure accounts for not even one-fifth of the possible factors listed, even that is padded since it covers not just those who are exceeding the speed limit, but also those who are "driving too fast for conditions" (a problem photo radar doesn't address). While it's certainly more dangerous to have an accident at higher speed (52.5 percent of fatal accidents occur in 55 mph or higher speed zones), NHTSA's data suggest speed alone doesn't account for most accidents. If it did, why would over one fourth of all crashes (26.1 percent) occur in speed limit zones of 30 mph or less, while 77 percent happen in 50 mph zones or less? By contrast, 60 mph or higher zones account for a paltry 8.1 percent of all accidents."

Mauz's contention that speed limits are too low (which affects the number of photo-radar citations as well as formulas for yellow-light intervals) isn't just the fanciful rambling of an underemployed traffic researcher. It is backed, albeit quietly, by no less an authority than the Federal Highway Administration. During the last decade, one FHWA study confirmed what any common-sense driver knows: Motorists, as the engineers like to say, drive the geometrics of the road. That is, they find the natural speed for a road and stick with it--regardless of the speed limit. This is why, if you conduct an unscientific experiment driving 55 mph on your local open stretch of highway, you will be passed by over two-thirds of your fellow motorists.

But the FHWA conducted a scientific experiment over a five-year period, and found that the 85th percentile speed--or the speed under which 85 percent of drivers travel--changed no more than 1 to 2 mph even when the speed limit changed 15 mph. In another study, the same engineers--one of whom was Dr. Samuel Tignor, who just retired as the FHWA's technical director for safety and research development--found that "current speed limits are set too low to be accepted as reasonable by the vast majority of drivers. Only about 1 in 10 speed zones has better than 50 percent compliance. The posted speeds make technical violators out of motorists driving at reasonable and safe speeds."