No truck crash is good – they are all bad, and ugly. Yet, relative to each other, large truck crashes can be divided into three distinct categories corresponding to these three adjectives. The three crash categories are quite different in their causal profiles and in what they tell us about driver risk.
The “good” truck crashes are those not caused by the truck or truck driver. In crash causation studies, these are car-truck or other multi-vehicle crashes where the “critical reason” (the principal or proximal cause) is not assigned to the truck. In other words, the other driver made the critical error triggering the crash. In 56% of the car-truck crashes in the Large Truck Crash Causation Study (LTCCS), the critical reason was assigned to the car. Other drivers are at fault in an even larger percentage of fatal crashes. In 2012 fatal car-truck crashes, 84% of cars were cited with a “driver factor” (i.e., error) versus just 30% of trucks. The percentages add to more than 100% because both drivers could be cited. Most of these “good” truck crashes are caused by car driver inattention (distraction, looked but did not see, etc.), driving too fast, following too closely, asleep-at-the-wheel, illegal maneuvers, or physical illness (usually, a heart attack).
The “bad” truck crashes are these same multi-vehicle crashes when caused primarily by the truck or truck driver. They are fewer in number than the “good” crashes, but similar in nature. By-and-large, truck drivers make the same kinds of errors in traffic that car drivers make – inattention, driving too fast, etc. But there are some differences. When trucks cause a multi-vehicle crash, it is relatively more likely to be due to an equipment failure. Another common truck-at-fault scenario is when the truck driver fails to see another vehicle when making a lane change, especially a left-to-right lane change where visibility is problematic. Compared to car drivers, truck drivers in car-truck crashes are much less likely to be speeding, driving aggressively, asleep-at-the-wheel, ill, or impaired by alcohol or drugs.
Multi-vehicle crashes, both “good” and “bad,” are strongly affected by traffic density and proximity. Your crash risk jumps about five-fold instantly as you leave an Interstate or other freeway and enter an undivided road with local traffic. There is an opportunity for error every time you approach another vehicle. While some driver errors are egregious misbehaviors, many are unintentional mistakes, much like bumping into someone at a store. Think of all the small mental and physical mistakes you might make in a single day, most of which have no consequences. Now make those same mistakes in a moving 80,000lb vehicle. Large trucks are the bulls in the china shop. They are generally well-behaved bulls, but still capable of great damage.
The “ugly” truck crashes are those involving only the truck. Here, “ugly” isn’t referring to crash consequences — single- and multi-vehicle truck crashes are, overall, about equally harmful. Rather, “ugly” refers to single-vehicle crash causes and their implications about future driver risk. What does it say about a driver if he or she cannot keep a vehicle upright and on the road? A single-vehicle crash typically involves a fundamental loss of vehicle control due to driver misbehavior (especially speeding), driver impairment (usually fatigue or physical illness), or a vehicle maintenance failure (e.g., brakes, tires). The truck driver is almost always culpable in a single-vehicle crash, whereas that’s true in fewer than half of multi-vehicle crashes. Comparing LTCCS single-vehicle crash involvements to multi-vehicle involvements (including both the “good” and the “bad”) finds that truck drivers in single-vehicle crashes were six times more likely to have caused the crash by speeding, eight times more likely by physical impairment, and 32 times more likely by falling asleep-at-the-wheel. They were also ten times more likely to be driving aggressively, and three times more likely to have not worn their safety belt. How would you describe these drivers’ future risk? Ugly!
Ron Knipling, President
Safety for the Long Haul Inc.
5059 36th Street, North
Arlington, VA 22207-2946
( (703) 533-2895