The percentage of truck drivers testing positive on random drug tests during 2011 dropped to the lowest level since mandatory testing began almost two decades ago.
The positive rate was 0.9% for the 492,000 drivers in the 2011 sample, DOT said.
The 2011 total was lower than the 1% of 455,000 drivers who tested positive in 2010, and less than half the 2.2% rate for the 438,000 drivers tested in 1996 when regulations first required all carriers to conduct random tests, according to data that DOT and its Federal Motor Carrier Safety Administration supplied Transport Topics.
Trucking industry leaders cautioned that the percentages may not accurately reflect drug use among drivers.
“We certainly think [the results are] encouraging, but we are very aware of the limitations of urine testing, so urge some caution in reviewing the results,” said Rob Abbott, vice president of safety policy for American Trucking Associations.
Carriers are required under federal law to do only urine testing on drivers and prospective hires, and many in the industry have concluded urine testing is not as effective as hair testing.
ATA supports changes that would allow carriers to choose between hair tests and urine tests for drivers.
“If our goal is to keep [drug users] from entering the industry, then hair is a superior gatekeeper,” Abbott said.
DOT, asked for comment on the results, said through spokesman Justin Nisly: “We work closely with our partners in the trucking industry on education and enforcement efforts, and we’re pleased that the positive drug test rate for truck drivers fell to an all-time low this year.”
The overriding issue between the two different methods is hair testing’s effectiveness.
“We get five to 10 times the number when you do side-by-side comparisons,” said Ray Kubacki, CEO of the testing firm Psychemedics Corp., which does hair testing for several carriers.