In 2001, after all trucks had either been manufactured with retro reflective DOT C2 tape that met NHTSA specifications, or had been retro-fitted, the agency conducted a study of the reflective tapes effectiveness in preventing accidents.
It was found that by treating a truck and trailer with DOT C2 with the minimum required retro reflective DOT C2 (2″ wide), in accordance with the regulation, accidents at night were reduced by 44%. (up to 5000 injuries and 350 fatalities prevented) The report, quoted below, covers a variety of important subjects and discusses the difficulty of night time visibility when it comes to the large on the road trucks and trailers.
Keep in mind that 2″ wide DOT C2 tape is the minimum standard. But C3 and C4 (3″ and 4″ wide) tapes are also available and would provide even more night time conspicuity, hence decreasing accidents. (see DOT C2 FMCSA regulation)
The full study performed by the NHTSA is below.
