NHTSA report: tyre underinflation, low tread contribute to highway accidents

ERJ staff report (TB)

Washington DC -- Tyres underinflated by 25 percent or more are three times as likely as properly inflated tyres to be cited as factors in highway crashes, the National Highway Traffic Safety Administration (NHTSA) found in a recent study.

Low tread depth and driver inexperience also add to tyre-related pre-crash vehicle problems, according to the April 2012 NHTSA study titled, “Tyre-Related Factors in the Pre-Crash Phase.”

The study uses data collected through the National Motor Vehicle Crash Causation Survey between 2005 and 2007, NHTSA said in the study's executive summary. Of the 5,470 crashes sampled in the survey, 9 percent of the vehicles had tyre problems before the crash, the agency said.

“Of the tyres that were underinflated by more than 25 percent of the recommended pressure, approximately 10 percent were in vehicles that experienced tyre problems in the pre-crash phase,” NHTSA said. “In contrast, among the correctly inflated tyres, a much smaller percentage (3.4 percent) belongs to vehicles that experienced tyre problems.”

About 26 percent of the tyres with tread depths of zero to 2/32 inch created problems on vehicles that crashed, NHTSA said, whereas only 8 percent of the tyres with 3/32- to 4/32-inch tread depth created problems.

The study found that tyre problems were significantly more in evidence among vehicles that rolled over in a crash compared with vehicles that didn't, the agency said. Forty-five percent of SUVS that had tyre problems rolled over, compared with less than 25 percent of other types of vehicles, it said.

“When drivers were less familiar with the vehicles they were driving, the vehicles experienced tyre problems in the pre-crash phase significantly more than chance,” the agency said. “This was also the case when drivers were inexperienced and lacked sufficient driver training.”

From Tire Business (A Crain publication)

Tire-Related Factors in the Pre-Crash Phase from NHTSA