Researchers analyzed evidence from around the world to get a sense of how much is known about how frequently truck drivers use legal and illegal “psychoactive” substances like alcohol, marijuana, amphetamines and cocaine.
They found widely varying estimates - based both on drivers’ own reports and on drug testing - but overall use of mind-altering substances was high and linked to poor working conditions.
The media often focuses on this problem in Brazil, said Edmarlon Girotto, who led the review at the Universidade Estadual de Londrina in the Brazilian state of Parana. As a result, he expected to find considerable drug use by truck drivers in his own country, but did not expect to see similar results in other developed countries.
Alcohol and driving don’t mix, and the case for marijuana is similar; both increase sleepiness, decrease concentration and could lead to accidents, Girotto and his colleagues write in Occupational and Environmental Medicine.
Amphetamines and cocaine may help drivers stay awake, the authors add, but can cause vertigo, agitation, hallucinations and change perceptions and reactions.
Girotto’s team included 36 previous studies in their review - most from large countries that rely heavily on trucking, like Brazil, the U.S. and Australia - and the rest from countries in Europe, Scandinavia and Asia.
The majority of studies relied only on what drivers admitted to taking in surveys, about a dozen were based on physical drug testing and two used both sources of data.
When drivers were asked, about half admitted to drinking and driving and 30 percent admitted to using amphetamines, on average. The numbers varied greatly from country to country, however, ranging from 9 percent of drivers in Pakistan to 91 percent in Brazil saying they drank alcohol. Similarly, amphetamine use ranged from less than one percent in Italy to 70 percent in Brazil.
Though drivers most frequently admitted to drinking alcohol, that was the substance found least often when they were given drug tests. But surveys and drug tests were usually given to different groups of drivers, so they can’t necessarily be compared side-by-side, the authors note.
About eight percent of drivers tested positive for amphetamines, compared to between three and four percent for alcohol, on average. For amphetamines, the testing results ranged from 0.2 percent of drivers in Norway to 83 percent in Thailand.
One U.S. study had the highest frequency of positive alcohol tests worldwide, at 12.5 percent.
Many drivers also tested positive for the stimulants caffeine and ephedrine, though these have not been linked to impaired driving.
Almost 20 percent of drivers reported they used marijuana and 3 percent said they used cocaine.
These results come from small, specific groups in many countries and can’t necessarily be applied to all truck drivers everywhere, the authors caution. More studies are needed to get a fuller picture of drug use among drivers.
“The consumption of psychoactive substances is an important risk factor for the individual and collective health,” Girotto said in an email. “Thus, we believe that use of these substances could affect the steering capacity.”
It could also give companies the impression that drivers can handle longer trips than they actually can, he told Reuters Health. All of these factors could lead to more accidents.
A dozen of the studies linked drug use to other lifestyle factors. Drug users were more likely to be young, inexperienced, to make more money, to have longer routes that often involved nighttime driving, to work for small or medium sized companies and to have previously been in an accident.
“Maybe big companies give better working conditions, which in addition to the salary, involve benefits such as food stamps and health plans,” Girotto said. “Also, we suggest that large firms are better able to ensure the drivers more time to rest, reducing the consumption of these substances.”
In Brazil only alcohol, benzodiazepines and opioids are legal in some amounts, Dr. Marcos Basíllio said. Basíllio is a physician with the Federal Highway Police of Brazil and was not involved in the review.
“Marijuana, cocaine, LSD, heroin and amphetamines are illegal, though easily found at gas stations and rest stop locations,” he told Reuters Health.
Brazil is first in the world in traffic accidents, which Basíllio believes is due to drowsiness and drug use.
Even when other drivers on the road are aware that truck drivers may be intoxicated, defensive driving is the only option, and many people fail to do that, he said.
Other drivers should be especially aware of trucks on the road, signaling and honking more than they perhaps otherwise might, Basíllio said.
A spokesperson for the U.S. Department of Transportation‘s Federal Motor Carrier Safety Administration (FMCSA) told Reuters Health in an email, “Safety is our number one priority and FMCSA has strict requirements on pre-employment screening and random and post-accident drug and alcohol testing. FMCSA’s own Drug and Alcohol Testing Surveys of U.S. drivers regularly show the positive rates for random drug and alcohol tests for the drivers we regulate is very low, around 1 percent.
“We acknowledge the pressure and daily demands on commercial motor vehicle drivers, but also believe the vast majority of truck drivers are dedicated professionals who would never jeopardize their careers, their safety and the safety of other travelers by using substances or medications that would adversely impact their ability to operate safely on the nation’s highways.”
Reducing travel hours would disincentivize drug use for truck drivers, Basíllio noted.
Girotto agreed, “Improving these working conditions, such as restricting the working hours and better pay (preferably not involving the salary based on production) could contribute decisively to reducing the consumption of these substances.” (Reuters)