Speed Limiters May Be Mandated On 18-Wheelers, Could Cut Top Speed To 68 MPH

May 6, 2014

Federal officials have a slew of new auto regulations in the works, including backup cameras, data recorders, and -- further down the line -- autonomous car standards. But the Department of Transportation's most controversial new rule might not involve passenger cars at all.

According to the insurance industry website Claims Journal, the DOT is proposing a new regulation to mandate speed limiters on big rigs. The rule will be sent to Transportation Secretary Anthony Foxx this month, and if he approves it, the regulation would then go on to the White House Office of Management and Budget in June. Should it pass that hurdle, it could appear in a Notice of Proposed Rulemaking this fall, around October. It would then be open to several months of public comment, after which the DOT could begin rolling out the new regulation as early as the latter half of 2015.

There's no word on what the DOT might want truckers' top speed to be, but previous proposals have mentioned upper limits of 68 mph. 


A speed limiter -- often called a governor -- does exactly what you'd think: it sets a vehicle's top speed. Different speed limiters work in slightly different ways, but the gist is that when a vehicle reaches its designated top speed, the limiter begins cutting the fuel supply and the air to the engine, curtailing combustion and, ultimately, speed.

Speed limiters are common on vehicles from mopeds to muscle cars. When you hear about an automobile being limited to a top speed, that often means that a speed limiter has been installed. They're also found on many 18-wheelers, with many fleet owners setting the top speeds at which their drivers can travel. The DOT's new proposal would make such limits uniform across the country.


Fleet owners and many consumer safety groups like the idea of mandatory speed limiters. So do industry organizations like the American Trucking Association. In 2006, several of those groups joined forces and petitioned the DOT to make speed limiters mandatory. To bolster their argument, the groups cited studies that showed the vast majority of traffic fatalities involving large trucks -- 73 percent of them, in fact -- took place on roads with speed limits of 55 or higher. Slowing those trucks down, they say, would decrease the stopping distance those large vehicles need and potentially save lives.

DOT stats from 2010 suggest that the problem of big-rig collisions may be worsening. That year, 3,413 people were killed in accidents involving large trucks -- an eight percent rise compared to 2009. And while 18-wheelers make up just four percent of vehicles registered in the U.S., they account for nine percent of roadway deaths. 

As you might imagine, truckers and the Owner Operator Independent Drivers Association dislike the proposal. They insist that speed isn't the cause of highway accidents, but rather differences in speed. They also lay the blame for many accidents on automobile drivers who don't understand the difficulty of maneuvering -- and stopping -- vehicles that weigh 26,000 pounds or more. 


We understand the rationale behind the desire to limit the speed of large trucks, but speed isn't the only problem on the roads. There are other factors that make big rigs dangerous, some of which have to do with the nature of the machines themselves (e.g. shifting cargo), and some of which have to do with the nature of the industry (e.g. driver fatigue). And the propose regulation would do nothing to address the two problems that truckers point out -- namely, differences in speed and car drivers who don't respect the problems that big-rig drivers face.

We're not opposed to government regulations, especially when they save lives. Clearly, seat belts, air bags, and other mandated safety features have led to record low roadway deaths in the U.S. However, we're not entirely sure that this DOT proposal gets to the heart of the problem. It addresses a symptom -- in this case, high speed -- without fixing more important, underlying safety problems, like trailer design, driver compensation, and even crumbling infrastructure, all of which make accidents more likely.


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