The DOT regulations resemble policies instituted for DOT employees and include pre-employment, postaccident, periodic, reasonable suspicion, and random testing. Employers are required to conduct random drug tests on 50 percent of covered workers each year, and testing costs are to be incurred by employers. The DOT regulations do not require employers to pay for rehabilitating employees who test positive for drugs. As of 1989, workers covered by the DOT regulations included 3 million truck drivers, 90,000 railroad workers, 538,000 airline employees, 120,000 maritime employees, 116,500 pipeline employees, and 195,500 mass transit employees. The DOT regulations have elicited both strong support and strong opposition, with random testing requirements generating the most controversy. Congressional initiatives related to transportation industry drug testing are noted, and policy considerations associated with the random drug testing of transportation workers are discussed. 7 references and 27 footnotes