Bus Expert Testifies Regarding Reaction Time

Bus expert witness Charles Scalia, owner of Scalia Safety Engineering of Madison, testified that the 78-year-old driver of a bus that slammed into an overturned semitrailer truck, killing five people 18 months ago, had plenty of time to stop if his recognition of the hazard and reaction time were normal.

According to the Winona Daily News, Scalia testified:

Normal reaction time for a driver seeing a hazard is 1.6 seconds, including time to perceive a problem, consider a course of action and start the reaction, Scalia said. The vehicle response time is typically .3 seconds, he said, making for a total reaction time of 1.9 seconds.

Scalia recreated the accident, and found the overturned semi, assuming some light from the bus’ headlights was reflecting off it, would be recognizable for a driver with normal vision at about 500 feet away.

Given that, a bus going 65 mph would have traveled 181 feet during the reaction time. At full braking with normal brakes it would take 235 feet to stop the bus, leaving the bus still 84 feet from the semi, he said.

At 71 mph, the estimated actual speed of the bus, which was filled with 44 band students, teachers and chaperones, it still stops 20 feet from the truck, Scalia testified.