Safety in Numbers

| May 29, 2007

One of the things that’s always overlooked is where the vast majority of accidents take place,” OOIDA’s Spencer says. “It’s not on roads that have the maximum speed limits.”

Only 14 percent of speeding-related fatalities occur on Interstates, the highways where speed governing would have its main impact because most non-Interstate highways have speed limits below 68 mph. Of that 14 percent, factors other than speeding are responsible for some accidents.

Even so, say McCartt and others, that’s no reason to shy away from speed governing. “The proposed rule should be evaluated more on its merits rather than on what it wouldn’t address,” she says. “Even on some non-Interstate highways, trucks can go at very high speeds.”

Blower suggests considering the data of large carriers with experience running governed and ungoverned trucks on Interstates to see whether governing appears to improve safety.

Given that two-thirds of states have higher speed limits on rural Interstates, the practicality of mandating a nationwide truck speed limit becomes more questionable. Add other variables, such as varying truck sizes and applications, and the issue is even more complicated, Murray says.

“Ultimately the question everyone in government and industry needs to resolve is: Do we promote a level playing field, or recognize that the complexity of the industry takes precedence, and one size does not fit all?” he says.

With more than 15,000 drivers and a long history of governing trucks, Schneider National is a safety experiment unto itself.

Schneider’s owner-operators drove 17 percent of the company’s miles in 2006 with ungoverned trucks, yet “they were involved in 40 percent of our potentially severe crashes,” the company says in its comments filed on the speed governing petition. “Since their exposure is comparable to our company drivers (whose trucks are governed at 65 mph), it’s reasonable to conclude that the most significant variable between the two groups is speed.”

Such experience may well be significant, says Dan Blower, a researcher at the University of Michigan Transportation Research Institute. Still, he cautions that the two driver groups need to be scrutinized for factors other than speeding, such as driver experience levels and types of equipment, that might affect crash rates.

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