While many truck accidents are the result of driver negligence, even the most experienced over-the-road drivers can’t stop the laws of physics when they find their rig in dangerous situation at highways speeds.
Some information every trucker knows, but car drivers may not
According to statistics reported by the Federal Motor Carrier Safety Administration (FMCSA) truck driver a critical factor in about 23 percent of all truck crashes. Predominantly because it often affects the truck driver’s ability to perform appropriately to a dangerous situation. The critical factors that figure into the speed equation include the truck driver’s perception distance; the trucker’s reaction distance; and the truck’s braking distance. All are figured relative to the speed of the truck.
- The time it takes for the trucker to perceive a problem ahead: Whether the situation requires appropriate braking, swerving or even speeding up, nothing can happen behind the wheel until the trucker perceives the danger and his brain engages. With the rig moving at 65 miles per hour on a highway, a trucker’s typical perception time of .75 seconds means the truck will travel nearly 72 feet; and that is before the driver begins to move a muscle. Indeed, some truck drivers may be quicker to perceive the problem, but just as many may be slower.
- The time it takes for the trucker to react: It will typically require an additional .75 seconds for an alert truck driver to begin engaging the brake or turning the steering wheel (in the case of swerving). This means that at 65 mph, the rig will travel an additional 72 feet before beginning to come to a stop.
- The time it takes to stop the rig: Stopping distance is directly related to the load weight and the road conditions. On dry pavement at 65 mph, it may take as long as five full seconds for the truck to complete to a full stop. This will mean the rig could travel upwards of another 400 feet, after the truck driver engages his perception and his body to react.
The math isn’t pretty. Altogether, a fully loaded 18-wheel semi-tractor trailer can take upwards of 550 feet to come to a stop in an emergency situation.
But the stopping time is only critical factor in truck accidents
In addition to stopping time, truckers know that the physical configuration of their cab and trailer causes many problems for themselves and other drivers on the road next them and behind them.
Truckers are trained to adjust their driver-side and passenger-side mirrors before hitting the road. Most do. Some do not. When there are two drivers splitting driving time on long runs, forgetting to adjust the mirrors when the second driver takes over may be more common. Many side-view mirrors on trucks today include convex mirrors to account for blind spots. Older trucks, however, may not be outfitted with these, however. The mirrors must be set so they see other vehicles driving on either side.
Managing the physical size of these behemoths
Truckers also know that their cabs and trailers do not behave the same way a car does when turning. Large trucks must start to negotiate a turn earlier; they take up roughly 30 percent more lane width than a sedan car; their trailers are given to wide swings during wind gusts; and they often become unstable when negotiating a curve at speeds that are too high for the degree of bank. This is why you will see many trucks crowd the “outside” of their lane before heading into a curve.
All of this means that truck drivers must not only know how to drive at the right speed, they must take into account variables that are affected by speed, road surfaces and weather conditions that automobile drivers rarely have to think about.
Learn more about the causes of truck accidents at our website page.