The University Record, September 28, 1992

UMTRI researchers recommend reflective tape for large trucks

By Terry Gallagher
News and Information Services

All large trucks in the United States may soon sport bands of candy-striped reflective tape to make them more visible at night, if recommendations of U-M researchers are adopted.

A federally funded study by the U-M Transportation Research Institute (UMTRI) indicates that making trucks more conspicuous to other drivers approaching from the side or rear could significantly cut car-truck collisions that result in many fatalities and injuries as well as expensive losses of property and productivity.

Present regulations require few running lights and reflectors. They do not make trucks visible enough to prevent other drivers from crashing into them.

The U-M researchers say trucks that are the most conspicuous to other drivers, including auto haulers and dump trucks, have the lowest number of accidents involving being struck from behind. Flat-bed trucks are far more likely to be involved in such collisions.

More than a quarter of all crashes involving a large truck and another vehicle are related to how well the sides and rear of the truck can be seen by the other motorist, according to the study.

Visibility-related crashes involving trucks are more severe than other truck crashes, the researchers say. Among such crashes at night, more than 47 percent resulted in a casualty, compared with only 34 percent for nighttime two-vehicle crashes in general.

“Car/truck collisions are relatively serious, for the car and its occupants at least, due to the great discrepancy in mass between the two vehicles,” according to Paul L. Olson, principal investigator of the study. “Even a relatively low-speed impact may result in serious injury or death for the car’s occupants.”

Sponsored by the National Highway Traffic Safety Administration of the U.S. Department of Transportation, the study may be used by the federal government as the basis for revised trucking regulations. Current federal regulations require a minimum of three lights and three reflectors on each side and one red light and one red reflector on the rear of a truck body or trailer that is 30 feet or longer.

Among the recommendations :

—Use of an alternating red-and-white pattern of reflective material in strips at least two inches wide, with approximately equal amounts of each color.

“This will provide good visibility and a pattern that will be easily recognizable as a hazard and, in time, come to be associated with large trucks,” according to Olson.

—Use of a broken or continuous red-and-white strip along the bottom of the sides and a continuous strip along the bottom of the back of the truck, along with white reflective markers at the top corners of the rear of the truck.

—The reflective material should be separated from turn signals and brake lights by about six inches so that brake lights remain a primary danger indication.

According to data compiled by interstate truck carriers in 1986, the mean cost of property damaged in conspicuity-related truck accidents was nearly $11,000 per crash. Similar accidents that resulted in a fatality had a mean cost of more than $16,000 per crash. In another study, one trucking company reported an average savings of $3,200 for each crash prevented in its fleet.

The U-M researchers conducted laboratory and field experiments to test patterns in truck markings and their placement on the vehicles, the relative performance of different reflective materials, and the effects of age and dirt on those materials on trucks in actual use.

Test subjects clearly preferred a pattern with equal amounts of red and white as a means of marking a potential hazard, according to Olson.

The U-M researchers examined records of 23,269 accidents in Michigan between 1985 and 1988 involving a large truck and another vehicle and found that nearly 6,000, or about 25 percent, were conspicuity related.

Other researchers involved in the study were Kenneth Campbell, Dawn Massie, Dennis S. Battle, Eric C. Traube, Toshiaki Aoki, Takashi Sato and Leslie C. Pettis.