1. What is a large truck?
Large trucks weigh more than 10,000 pounds and can be either single-unit vehicles or combination vehicles consisting of a single-unit truck or tractor pulling one or more trailers. In most states, the maximum permitted length for a single trailer is 53 feet. Tractors pulling two 28-foot trailers are known as twins or western doubles. Trucks even bigger than western doubles are allowed to travel on some of the nation's roads. These trucks, called longer combination vehicles, either have three trailers or have at least two trailers, one of which is 29 feet or longer, or the tractor and two trailers have a combined weight exceeding 80,000 pounds.
2. Do large trucks have high crash rates?
Large trucks are involved in more fatal crashes per unit of travel than passenger vehicles -- compared with 1.8 crashes per 100 million miles traveled in 2002. The disparities between large trucks and passenger vehicles vary by specific vehicle type, with passenger cars having the lowest fatal involvement rate and tractor-trailers having the highest rate. The higher fatal involvement rate for large trucks occurs although a much higher proportion of their miles is traveled on interstate highways, which are the safest roads. Their higher fatal involvement rate is attributable to the size disparity between large trucks and passenger vehicles. Tractor-trailers have a lower rate of nonfatal crashes resulting in injuries or property damage only, compared with passenger cars.
3. Who dies in crashes involving large trucks?
About 5,000 people die each year in crashes involving large trucks and about 85 percent of them aren't truck occupants. In fatal two-vehicle crashes involving passenger vehicles and large trucks, 98 percent of the deaths occur to the people in the passenger vehicles. Large trucks accounted for 3 percent of registered vehicles and 8 percent of vehicle miles traveled in 2002 but were involved in 11 percent of all passenger vehicle occupant deaths and in 21 percent of multiple-vehicle passenger vehicle occupant deaths.
4. Are multiple-trailer trucks more likely to crash than single-trailer trucks?
Multiple-trailer trucks have more handling problems than single-trailer trucks. In general, the additional connection points contribute to greater instability, which can lead to jackknifing, overturning, and lane encroachments. But the relationship between multiple-trailer trucks and crash risk isn't firmly established. A study in Washington state found doubles (tractors pulling two trailers) were two to three times as likely as other rigs to be in crashes, but a study in Indiana found doubles didn't show increased crash risk except on roads with snow, ice, or slush. Doubles often are operated by drivers with good safety records working for large companies with active safety programs.
5. Who oversees large truck safety in the United States?
Two agencies of the U.S. Department of Transportation and the states oversee large truck safety. The National Highway Traffic Safety Administration (NHTSA) sets standards for new truck equipment and has some jurisdiction over equipment standards for trucks currently on the road. The Federal Motor Carrier Safety Administration (FMCSA) oversees the safety of commercial vehicles in interstate commerce, and this agency's regulations cover equipment, licensing, hours of service, and vehicle inspections and maintenance. The rules pertaining to licensure, vehicle maintenance and hours of service are primarily enforced by the states. States regulate intrastate trucks.
6. Do truck drivers need special licenses?
Commercial drivers' licenses have been required since 1992 for commercial vehicle operations. Each driver holding a commercial drivers license is entered into a national database. This requirement is intended to ensure that truckers do not use multiple state licenses to conceal the overall total of their traffic violations. Both interstate and intrastate commercial drivers must obtain such licenses if they operate trucks with gross vehicle weight ratings of 26,001 or more pounds, if they transport 16 or more passengers, or if they transport hazardous materials.
7. Are there age restrictions on who is permitted to operate large trucks?
If large trucks cross state lines or if they carry hazardous materials, their drivers must be at least age 21. States permit drivers ages 18-20 to operate large trucks only within the state.
8. Are young truck drivers at higher risk of crashing?
Yes. Studies conducted in the United States, New Zealand, and Australia indicate that truck drivers younger than 21 and in their 20s have a high rate of involvement in both fatal and nonfatal crashes.
9. Is driver fatigue a factor in truck crashes?
Yes. Driver fatigue is associated with truck crashes. Research shows truck crash risk increases with driver hours behind the wheel. Crash risk is also higher between midnight and 6 a.m. The long hours truck drivers work cause sleep deprivation, circadian desynchronization, and fatigue. The Institute has found that truck drivers reporting hours-of-service violations were more likely to report having fallen asleep behind the wheel during the month before the interview. The proportion of large truck crashes for which fatigue is a contributing factor is uncertain.
10. What are the hours-of-service rules (work hour limits) and who violates them?
Under federal hours-of-service regulations that took effect January 2004, interstate commercial truck drivers won't be allowed to drive more than 11 hours or drive after 14 hours on duty until they have had a 10-hour break. Drivers cannot drive after accruing 60 work hours during a 7-day period or 70 work hours during an 8-day period, but a "restart" provision will allow truckers to drive 77 hours in 7 days or 88 hours in 8 days. Studies suggest that work rules are commonly violated.
11. How can violations of the hours-of-service rules be reduced?
Current regulations allow drivers to use written logbooks of their hours, which truck drivers call "comic books" because they are so easily falsified. Onboard computers reduce the opportunities for violating the rules because they automatically record when a truck is driven and its speed. Europe has required mechanical tachographs, which are nonelectronic devices designed to record vehicle travel hours, for about 30 years. Mechanical tachographs can be more easily falsified than onboard computers, so by August 2004, new trucks and intercity buses registered in the European Union must be equipped with electronic recording devices. The Institute and five other organizations petitioned the Department of Transportation to require the installation and use of tamper-resistant electronic onboard computers on commercial vehicles whose drivers now are required to maintain written logbooks. The National Transportation Safety Board also has repeatedly recommended that such recorders be mandated. In 2000, FMCSA published a proposal to require these devices but dropped the proposal from the final work-hour rules that take effect January 2004.
12. Is the use of alcohol and other drugs among truckers a big problem?
Alcohol is much less of a problem among truck drivers than among passenger vehicle drivers. Only 6 percent of all tractor-trailer drivers who were killed in crashes during 2002 had blood alcohol concentrations of 0.08 percent or more, compared with 32 percent of fatally injured passenger vehicle drivers. A 1995 roadside study in four states found that almost 5 percent of truck drivers tested positive for illicit drug use but only 0.2 percent tested positive for alcohol. This study did not test for use of legal over-the-counter stimulants, which were present in 12 percent of truck drivers in an earlier Institute study. In 1999 almost 3 percent of drivers of large trucks tested positive for illicit drugs after a non-fatal crash. Federal regulations require carriers to test all commercial drivers for drugs before employment, after crashes, and on a random basis. Alcohol tests are required only after crashes and on a random basis. New alcohol test rules were issued in 1994 that place drivers out of service if they are found with any alcohol in their systems.
13. Are radar detectors legal in large trucks?
Radar detector use is banned in commercial vehicles involved in interstate commerce. The Institute and other organizations petitioned for such a regulation in 1988 and again in 1990 because the only use for radar detectors is to evade speed limit enforcement. FHWA issued the ban on detectors, effective in 1994, but did not specify a mechanism for enforcement.
14. Are large trucks prone to rolling over?
Yes. The high center of gravity of large trucks increases their risk of rolling over, particularly on curving ramps. A little more than half of deaths among occupants of large trucks occur in crashes in which their vehicle rolled over, compared with about 60 percent of SUV occupant deaths and 45 percent of pickup occupant deaths (both SUVs and pickups also have high centers of gravity). In contrast, about 25 percent of passenger car occupant deaths occurred in vehicles that rolled over.
15. Is defective equipment a factor in truck crashes?
Yes. Institute researchers who examined crashes of large trucks in Washington state found that tractor-trailers with defective equipment were twice as likely to be in crashes as trucks without defects. Brake defects were most common. They were found in 56 percent of the tractor-trailers involved in crashes. Steering equipment defects were found in 21 percent of crash-involved trucks. The proportion of large truck crashes in which defective equipment is a contributing factor is uncertain. Underride guards prevent many of the deaths and injuries that occur in rear impact crashes.
16. How effective are truck brakes?
Compared with passenger vehicles, stopping distances for trucks are much longer. On wet and slippery roads there are greater disparities between the braking capabilities of large trucks and cars. Brake problems will be aggravated by poor maintenance practices. Out-of-adjustment brakes are the most common reason for authorities to order trucks out of service. New large trucks must have automatic brake adjusters, visible brake adjustment indicators, and antilock brakes. Antilock brakes, which keep wheels from locking, improve driver control of trucks during emergency stops and reduce the likelihood of jackknife in tractor-trailers.
17. When were large trucks required to have antilock brakes?
NHTSA issued a rule in 1995 requiring antilock brakes on newly manufactured medium and heavy vehicles. They were on new tractors as of March 1997 and on new trailers, single-unit trucks, and buses as of March 1998. Antilocks are required on all new trucks, buses, and trailers in Japan and the European Union.
18. What are truck underride crashes?
In an underride crash, a passenger vehicle goes partially or wholly under a truck or trailer, increasing the likelihood of death or serious injury to the passenger vehicle occupants. A 1997 Institute study of fatal crashes between large trucks and cars estimated that front, rear, or side underride occurred in half of these crashes. A federal rule to upgrade the rear impact guard standard for new trailers only took effect in January 1998. The new guard will prevent many of the deaths and injuries that occur in rear impact crashes.
19. Can trucks be made more visible to other drivers at night?
During the day, trucks are easy to see, but it's a different story at night. Research indicates that if drivers of other vehicles can recognize medium and heavy trucks more easily, these drivers can gauge the trucks' speed and distance more accurately and react sooner when necessary. Federal studies have reported that enhancing the conspicuity of trailers reduced the incidence of crashes in which trailers were hit from the side or rear at night on unlighted roads. A federal rule requires improved conspicuity -- adding reflective sheeting or reflectors -- for trailers manufactured after December 1993 and truck tractors (bobtails) manufactured after July 1, 1997. Starting June 1, 2001, the Department of Transportation required the enhanced markings for all trailers on the road, not just new ones.
20. Are Mexican and Canadian trucks allowed to operate in the United States?
Canadian trucks are allowed to deliver loads from Canada and pick up loads with a Canadian destination, but generally cannot pick up U.S. loads with a U.S. destination. At this time, Mexican trucks are restricted to border cities, but the U.S. government has announced its intentions to permit Mexican motor carriers the same access to the United States as Canadian motor carriers, provided they meet certain safety and insurance requirements. Because of legal challenges, these plans currently are on hold. At least initially, few Mexican motor carriers have applied for such operating authority.
21. Do Mexican trucks pose a safety risk on U.S. highways?
Data on the crash experience of Mexican trucks are insufficient to determine if they have a higher crash risk than U.S. trucks. Past safety inspection data indicate that out-of-service rates for Mexican trucks were lower within California, a state with a stringent inspection program, than in the three other border states with less frequent inspections. However, within the past few years, more safety inspectors have been hired and border inspection facilities have been improved. Information from IIHS.
