Highway Torpedos

A year and a half after the incident, it's still hard to imagine the carnage.

The driver of a tractor trailer loaded with scrap metal ran a stop light in the middle of a busy suburban area and rammed a total of four cars. The first car took the brunt of it, the full force of the impact. In a single second, the driver of that car suffered a crushed pelvis, two broken legs, two broken arms, multiple broken ribs, a collapsed lung, and a lacerated liver. The worst of it, though, was the cervical spine fracture that will keep him confined to a wheelchair and attached to a respirator for the rest of his life.

We're talking here about a man with several small children who had just returned from his fourth tour in Iraq and Afghanistan. For him, a drive in the family car proved to be more hazardous than bullets in a war zone.

According to the insurer, the company that owned the offending truck has already burned through the $4 million in insurance coverages and now is facing the kind of very dark choices that business owners hate—the kind of choices where you pray to all things holy that your corporate veil is 100 percent intact.

When you think about it, it's hard to wrap your head around the notion that so much misery can be caused by a single moment of driver inattentiveness.

For the record, I'm told that no official cause has been assigned for the accident, but apparently certain facts are not in dispute: the truck went through a red light and a post-accident vehicle inspection showed no mechanical deficiencies in the truck.

For the sake of argument, then, let's say that driver inattentiveness played at least a part. Much has been written in the news recently about how cell phone use and text messaging create significant hazards on the road. I take the data at face value, but I would argue that those distractions are but a few of many that create hazards—things like eating, drinking, and adjusting the radio. At the end of the day, it all comes down to precious few seconds that either save lives or ruin them.

Highway safety experts agree that a fully attentive driver takes as long as two seconds to react to an approaching hazard. That's the time it takes for the driver to realize that something's not right and then move his foot from the accelerator to the brake pedal. (SWAT teams use the same assumption of a two-second reaction time during assault operations.)

At 50 miles per hour, a vehicle will have traveled 147 feet during that two seconds of reaction—and that's if the driver is fully attentive. Once the brakes are applied, assuming that the brakes and the tires are in perfect shape, the vehicle will eat up another 119 feet in actual stopping distance. In a perfect world, then, if man and machine do everything exactly right, a vehicle traveling at 50 miles an hour will eat up 266 feet of roadway as it comes to an emergency stop.

Add in a two-second distraction, and we're up to 413 feet, or one and a half football fields.

If you're feeling a little cocky as you read this because you don't drive anything larger than the family sedan, give yourself a little slap because the numbers for stopping distance remain essentially identical regardless of the size of the vehicle. Think about it: brake size is commensurate to the size of the vehicle.

One of the reasons why motor vehicle accidents happen with such frequency is because drivers frequently forget (or have never learned) the physics of driving. Take a look at the table, which shows the various elements of reaction and stopping distance as a function of vehicle speed.

Try to remember it next time you're making the decision to dial your phone or pick up that dropped French fry.

—John Gilstrap,
Director of Safety