Speed kills, especially when it’s a 80,000 pound tractor-trailer driving over the speed limit.
Tractor-trailers are a major source of traffic fatalities and speed figures prominently in many of these accidents. Tractor-trailers take 20% to 40% longer than passenger cars to stop, and trucks traveling at high speeds take even longer than that, making them more likely to get into accidents. A new rule by the Department of Transportation (DOT) will cap the top speed at which these trucks can drive.
DOT to Require Speed Limitation Devices
The new rule would require new tractor-trailers to include electronic devices called electronic control modules (ECM) which limit how fast these trucks can drive. The rule would affect most large trucks, applying to all vehicles over 26,000 pounds that travel on roads with speed limits in excess of 55 mph. All new trucks would be required to be equipped with the devices. Road Safe America, a safety advocacy group, advocates retrofitting all vehicles built since 1990 but it remains to be seen which vehicles, if any, will be required to be retrofitted.
A report by the DOT suggests the rule could go into effect as early as October, though the DOT has not set a clear deadline. It’s possible the rule will be pushed back to a late date or phased in over time. And it will likely undergo several changes between now and when it goes into effect.
Though the DOT hasn’t yet determined to what extent speed will be limited, a current proposal suggests capping speed limits at 68 mph. Safety studies suggest that this speed cap would eliminate 1,115 fatal crashes every year. In 2010, there were over a million interstate crashes involving large trucks. Many of these crashes could have been prevented if tractor-trailer drivers followed the speed limit. And even when a crash is unavoidable, obeying the speed limit can reduce the severity of the wreck.
How Speed Limiting Devices Work
Speed limiting devices like ECMs work by directly interacting with a car’s computer. The devices use a number of calculations, then provide information to the truck’s computer about its speed. When the truck reaches its maximum speed, the computer then reduces the flow of fuel and air to the truck’s engine, thereby reducing power available to the vehicle and capping its speeds.