Three New Safety Recommendations Would Improve Tractor-Trailer Safety

The National Transportation Safety Board (NTSB) urged the National Highway Traffic Safety Administration (NHTSA) to take action to improve tractor-trailer safety by issuing several recommendations in April 2013. The recommendations address three areas of concern.

Blind Spots

Blind spots around tractor-trailers result in collisions with passenger vehicles or vulnerable road users because the driver of the tractor-trailer cannot see them. These blind spots are larger than those of passenger vehicles and exist on the front, sides, and rear of the tractor-trailer. Driver ride height, locations and characteristics of mirrors and windows, and vehicle geometry can affect the ability of drivers of tractor-trailers to detect passenger vehicles and vulnerable road users. The blind spot on the right side of the tractor-trailer is especially concerning because it impinges on a large portion of the driver’s field of view and is disproportionately involved in collisions involving pedestrians, cyclists, and passenger vehicles.

Technology that can mitigate blind spots already exists and more advanced technology is being developed. Enhanced mirror systems, for example, can reduce tractor-trailer collisions due to blind spots. Pedestrian sensing systems combined with automatic braking that are already installed on some passenger vehicles could also reduce these collisions. One of the most promising technologies is blind spot camera monitoring that will alert the driver when a vehicle or pedestrian is in the side or rear blind spot. NTSB recommends that NHTSA require that newly manufactured truck-tractors weighing more than gross vehicle weight ratings of 26,000 pounds be equipped with visibility enhancement systems. However, NTSB does not specify the type of technology it believes to be best.


One reason why collisions with the sides and backs of trailers are so hazardous is that underride may occur in these collisions. Underride occurs when the vehicle is small enough to slide under the trailer upon impact. Side and rear underride collisions are an important safety problem because they defeat crumple zones and prevent air bag deployment, both vital safety advances in improving protection of passenger vehicle occupants during crashes. Most of the fatal injuries associated with these collisions could be mitigated by stronger and lower underride guards. The NTSB recommends that NHTSA require newly manufactured trailers with gross vehicle weight ratings exceeding 10,000 pounds and newly manufactured truck-tractors with gross vehicle weight ratings more than 26,000 pounds be equipped with side underride protection systems. Further, NTSB recommends that NHTSA revise requirements for rear underride protection systems for newly manufactured trailers with gross vehicle weight ratings over 10,000 pounds to ensure that they provide adequate protection of passenger vehicle occupants from fatalities and serious injuries resulting from full-width and offset trailer rear impacts.

Tractor-Trailer Safety Data

Having accurate trailer data is important for evaluating the effects of safety regulations and for determining the safety of trailer designs. About 80 percent of the collisions between passenger vehicles and the rears of tractor-trailers involve the trailer rather than the truck-tractor cab; the corresponding percentage for passenger vehicle collisions with the sides of tractor-trailers is more than 50 percent. Although the majority of collisions involving the sides or rears of tractor-trailers consist of impacts to the trailers, police accident reports provide less information for trailers than for other types of motor vehicles.

Few police accident report forms include spaces for the vehicle identification number (VIN) or license plate numbers of trailers. Neither do the forms instruct police officers to fill in this information for trailers. The VIN can be decoded to indicate the trailer manufacturer, model year, and other trailer characteristics. The license plate number is a link to state vehicle regis­tration records containing the trailer VIN. The NTSB recommends that NHTSA add trailer vehicle identification number and trailer model year to the Fatality Analysis Reporting System database for trailers with gross vehicle weight ratings in excess of 10,000 pounds.

If you need more information on this subject, contact Boyd Newton at 404-593-2630 or by email at