Thirty Years of Dutch Drugs and Driving Research: Strengths and Limitations of the On-The-Road Highway Driving Test and Future Challenges

The Dutch on-the-road driving test is a standardized test, conducted on a public highway in actual traffic. Participants are instructed to drive for 100-km, while maintaining a steady lateral position and constant speed (95 km/h). Standard Deviation of Lateral Position (SDLP) is the primary outcome measure of the test. This review summarizes the results of 30 years of Dutch on-the-road driving research applying this test. Many central nervous system (CNS)-drugs show dose-dependent impairment on the driving test, expressed in significantly elevated SDLP values relative to placebo. This review discusses several determinants of drug-related driving impairment, including those related to the drug, its use, driver demographics, and the environment. Implications for study design, and limitations of the current methodology are discussed, as well as future challenges to improve the methodology. Overall, the on-the-road driving test has proven to be a reliable and sensitive test to assess the potential effects of CNS drugs on driving ability.