According to numbers compiled by the National Highway Traffic and Safety Administration (NHTSA), almost 4,000 people die, and an estimated 95,000 are injured every year in crashes involving large trucks on U.S. highways. 71 percent of those who died were occupants of other vehicles, while 11 were pedestrians, bicyclists, and others not in vehicles.

32 percent of bicyclist fatalities came from crashes with large trucks in New York City between 1996 to 2003, according to city statistics. Eight of the nine bicyclists killed in Boston from 2012 to 2014 died in crashes involving large trucks.

A safety element exists that could help save lives and is already mandatory on trucks in most of Europe and Japan.

Side guards work by physically covering that exposed space, shielding vulnerable road users from being swept underneath the truck’s rear wheels. For pedestrians, cyclists, and car passengers, they can be lifesavers. Side guards could also help prevent a car from sliding underneath the side of a semi truck, hopefully, to save lives. Side guards have been tested by the Insurance Institute for Highway Safety (IIHS) with excellent results.

Side guards won’t necessarily reduce the number of truck-involved crashes. However, they do seem to limit the number of fatalities resulting from accidents with trucks.

In a report published by Volpe, The National Transportation Systems Center, for NYC Citywide Administrative Services says fatal side-impact collisions between bicyclists and trucks dropped 61 percent after the U.K. required side guards on all large trucks.

Some American cities, including Boston, Portland, and Seattle, have begun experimenting with installing side guards on city-owned vehicles.

Side guards can be included in new fleet vehicles or retrofitted on older trucks.

How much does it cost? Side guard installation can be pricey, with costs between $1,000 to $2,000 per vehicle. The installation cost is small compared to the high price of lost lives. Hopefully, side guards will become standard equipment on trucks around the country.