Single-unit trucks or tractors pulling one or more trailers qualify as large if they weigh more than 10,000 pounds. Potential hazards of these vehicles involve both their drivers; particularly how long they work at a stretch, and the equipment including the brakes.
Do large trucks have high crash rates?
They don't have high overall crash rates, but their fatal crash rates are higher than for passenger vehicles (cars, minivans, pickups, and SUVs). On average, large trucks travel many more miles than passenger vehicles, and they're involved in more fatal crashes per mile traveled — 2.1 per 100 million miles compared with 1.7 for passenger vehicles in 2004. The rate is highest for tractor-trailers (2.4) and lowest for cars (1.5) vehicle crashes involving a large truck and a passenger vehicle, 98 percent of the deaths are people in the passenger vehicles.
Are rigs hazardous, or is the problem mostly drivers?
Large truck equipment is a factor in crashes. In the late 1980s Institute researchers examined crashes of large trucks in Washington sate, finding that tractor-trailers with defective equipment were twice as likely to be in crashes as truck rigs without defects. Brake problems were the most common, found in 56 percent of the tractor-trailers involved in crashes.
Can monitoring of truck driving hours be improved?
A problem is that truckers keep track of their own hours in written logbooks, notoriously underreporting their driving time. Onboard computers reduce opportunities for violating work rules by automatically recording when a truck is driven and its speed. Such equipment is required in EU countries, and the Institute and others repeatedly have asked the government to require tamper-proof recorders in trucks on US roads (see Status Report, July 26, 1997; on the web at iihs.org). But the government doesn't require them.
Are licensing requirements rigorous for truckers?
Compared with getting a license to drive a car or other passenger vehicle, truck drivers have to be older — at least 21 to drive a big rig that crosses state lines or carries hazardous materials. This is important because studies conducted in the United States and elsewhere indicate that truckers in their 20s and younger have high crash rates.
Who dies in large truck crashes?
Mostly it isn't the truck drivers. About 85 percent of the 5,000 or so people who die every year in crashes involving large trucks are in vehicles that collide with the trucks, or they're others on the road including pedestrians. In twoStatus Report, Vol. 41, No. 6, July 15, 2006.
How good (or bad) are truck brakes?
Truck stopping distances are much longer than for cars. On wet and slippery roads, the disparities are greater. Brake problems are aggravated by poor maintenance. Out-of-adjustment brakes are the most common reason for authorities to order trucks out of service.
Do trucks need antilock brakes?
Antilocks are intended to help drivers of all kinds of vehicles maintain control during emergency stops, but the safety benefits haven't panned out for cars. The antilocks on many models haven't reduced crashes. In contrast, the federal government requires antilocks on big trucks because of their poor braking capability, compared with cars, and because of their potential to jackknife. Antilock brakes shorten truck-stopping distances on wet and slippery roads and help drivers maintain control.
What's underride? Is this still a big problem or has it declined?
In an underride crash, a passenger vehicle goes partially or all the way under a truck or trailer, increasing the likelihood that the passenger vehicle occupants will be killed or seriously injured. A 1997 Institute study of fatal truck-car crashes estimated that underride occurred in half of these collisions. A 1998 federal rule upgraded the requirements for underride guards on the backs of trucks, but no rules address front or side underride. For answers to 22 questions about trucks, go to iihs.org/research.
