Robert J. Lokan

Bio: Robert J. Lokan is an academic researcher. The author has contributed to research in topics: Blood alcohol content & Benzodiazepine. The author has an hindex of 3, co-authored 4 publications receiving 368 citations.

The relationship between blood benzodiazepine concentration and vehicle crash culpability

Abstract: Objective: The purpose of this study was to determine the relationship between blood benzodiazepine concentration and crash risk. Methods: Blood samples from 2500 injured drivers were analyzed for benzodiazepines and the relationship between concentration and crash risk was assessed using culpability analysis. Benzodiazepine concentrations were expressed as a proportion of the peak concentration of the drug in blood or plasma for a standard therapeutic dose of the drug. Results: There were 68 drivers (2.7%) who tested positive for at least one benzodiazepine. Of these, 16 (23.5%) also tested positive for alcohol. Drivers who tested positive for benzodiazepines, either alone or in combination with alcohol, had a higher culpability rate than drug-free drivers. There was a significant linear relationship between benzodiazepine concentration and culpability for drivers who tested positive for benzodiazepines alone. Conclusion: The results here provide clear evidence of increased culpability associated with benzodiazepine use, which was marked at higher concentrations.

Acute cannabis consumption and motor vehicle collision risk: systematic review of observational studies and meta-analysis

Abstract: Objective To determine whether the acute consumption of cannabis (cannabinoids) by drivers increases the risk of a motor vehicle collision. Design Systematic review of observational studies, with meta-analysis. Data sources We did electronic searches in 19 databases, unrestricted by year or language of publication. We also did manual searches of reference lists, conducted a search for unpublished studies, and reviewed the personal libraries of the research team. Review methods We included observational epidemiology studies of motor vehicle collisions with an appropriate control group, and selected studies that measured recent cannabis use in drivers by toxicological analysis of whole blood or self report. We excluded experimental or simulator studies. Two independent reviewers assessed risk of bias in each selected study, with consensus, using the Newcastle-Ottawa scale. Risk estimates were combined using random effects models.

A review of drug use and driving: epidemiology, impairment, risk factors and risk perceptions

Abstract: The existing literature on the prevalence of drug driving, the effects of drugs on driving performance, risk factors and risk perceptions associated with drug driving was reviewed. The 12-month pre...

Cannabis intoxication and fatal road crashes in France: population based case-control study

Abstract: Objectives To evaluate the relative risk of being responsible for a fatal crash while driving under the influence of cannabis, the prevalence of such drivers within the driving population, and the corresponding share of fatal crashes. Design Population based case-control study. Participants 10 748 drivers, with known drug and alcohol concentrations, who were involved in fatal crashes in France from October 2001 to September 2003. Main outcome measures The cases were the 6766 drivers considered at fault in their crash; the controls were 3006 drivers selected from the 3982 other drivers. Positive detection of cannabis was defined as a blood concentration of Δ 9 tetrahydrocannabinol of over 1 ng/ml. The prevalence of positive drivers in the driving population was estimated by standardising controls on drivers not at fault who were involved in crashes resulting in slight injuries. Results 681 drivers were positive for cannabis (cases 8.8%, controls 2.8%), including 285 with an illegal blood alcohol concentration (0.5 g/l). Positive cannabis detection was associated with increased risk of responsibility (odds ratio 3.32, 95% confidence interval 2.63 to 4.18). A significant dose effect was identified; the odds ratio increased from 2.18 (1.22 to 3.89) if 0 9 tetrahydrocannabinol 9 tetrahydrocannabinol 5 ng/ml. The effect of cannabis remains significant after adjustment for different cofactors, including alcohol, with which no statistical interaction was observed. The prevalence of cannabis (2.9%) estimated for the driving population is similar to that for alcohol (2.7%). At least 2.5% (1.5% to 3.5%) of fatal crashes were estimated as being attributable to cannabis, compared with 28.6% for alcohol (26.8% to 30.5%). Conclusions Driving under the influence of cannabis increases the risk of involvement in a crash. However, in France its share in fatal crashes is significantly lower than that associated with positive blood alcohol concentration.