title: A pooled analysis of on-the-road highway driving studies in actual traffic measuring standard deviation of lateral position (i.e., "weaving") while driving at a blood alcohol concentration of 0.5 g/L.
abstract: The on-the-road highway driving test is generally regarded as a gold standard for assessing drug-induced driving impairment. The primary outcome measure is the standard deviation of lateral position (SDLP), a measure of road tracking error or "weaving". The test has been calibrated for incremental doses of alcohol almost 30 years ago in order to define the impact of drug-induced impairment in terms of blood alcohol concentration (BAC) equivalents. Drug-induced changes in SDLP exceeding 2.4 cm have been evaluated as clinically relevant ever since. The present analysis was conducted to assess the robustness of the alcohol effect in a range of on-the-road driving studies which have been conducted since the initial alcohol calibration study.
  
  
  
  The present study pooled data of 182 participants from nine placebo-controlled crossover studies who performed the highway driving test, while their BAC was at or just below the legal limit for drivers (i.e., 0.5 g/L).
  
  
  
  Overall, mean SDLP increased with 2.5 cm (95% CI 2.0-2.9 cm). Equivalence testing showed that the clinical relevance criterion value of 2.4 cm fell well within the 95% CI in each individual study. Gender did not affect alcohol-induced changes in SDLP.
  
  
  
  These results demonstrate the robustness and validity of the clinical relevance criterion for SDLP as measured during on-the-road driving.
authors.affiliation: Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Universiteitssingel 40, 6200 MD, Maastricht, The Netherlands. stefan.jongen@maastrichtuniversity.nl.
authors.forename: S
authors.initials: S
authors.lastname: Jongen
authors.affiliation: Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Universiteitssingel 40, 6200 MD, Maastricht, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Vermeeren
authors.affiliation: Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Universiteitssingel 40, 6200 MD, Maastricht, The Netherlands.
authors.forename: N N J J M
authors.initials: NN
authors.lastname: van der Sluiszen
authors.affiliation: Federal Highway Research Institute (BASt), Section U3/Traffic Psychology, Traffic Education, Bruederstrasse 53, D-51427, Bergisch Gladbach, Germany.
authors.forename: M B
authors.initials: MB
authors.lastname: Schumacher
authors.affiliation: Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Universiteitssingel 40, 6200 MD, Maastricht, The Netherlands.
authors.forename: E L
authors.initials: EL
authors.lastname: Theunissen
authors.affiliation: Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Universiteitssingel 40, 6200 MD, Maastricht, The Netherlands.
authors.forename: K P C
authors.initials: KP
authors.lastname: Kuypers
authors.affiliation: Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Universiteitssingel 40, 6200 MD, Maastricht, The Netherlands.
authors.forename: E F P M
authors.initials: EF
authors.lastname: Vuurman
authors.affiliation: Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Universiteitssingel 40, 6200 MD, Maastricht, The Netherlands.
authors.forename: J G
authors.initials: JG
authors.lastname: Ramaekers
mesh_terms: D000328:Adult; D001334:Automobile Driving; D000067401:Blood Alcohol Content; D018592:Cross-Over Studies; D000066448:Driving Under the Influence; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011597:Psychomotor Performance; D055815:Young Adult
chemical_list: D000067401:Blood Alcohol Content
keywords: Alcohol; Clinical relevance; On-the-road driving; Standard deviation of lateral position