Cannabis use has increased in the young adult population and its effect on motor vehicle control is still not well studied. To build on previous research, the current study looks at variability in vehicle control among young adult drivers who use cannabis compared to young adult drivers who do not use cannabis.
Data for this study was pulled from studies completed at the National Advance Driving Simulator at the University of Iowa. Inclusion criteria included 18-23 years of age and being a license driver who drives at least 5,000 miles per year. Participants in the cannabis group also had to have used cannabis at least once every 3 months and no more than 3 times per week. The nonusers had to report no drug use and pass a drug screening. The final group analyzed included 12 participants in the user group and 18 in the nonuser group. The driving analysis simulated a driving scenario that was 35-40 minutes and length with urban, interstate, and rural driving conditions. Variables measured included lateral control such as lane position, steering frequency, and steering reversal rate. Longitudinal measures were average speed, accelerator pedal holds, and accelerator pedal reversal rate.
Results showed there were no significant differences in lane position or accelerator pedal reversal rate. Cannabis users had significantly lower steering frequencies, lower average steering reversal rates, and less variability in steering reversal rates. The longitudinal controls showed that cannabis users drove slower, exhibited more accelerator pedal holds, and had a higher average accelerator pedal reversal rate. These results provide that cannabis users have a more passive engagement when driving and may experience deficits in underlying executive control faculties. Further research should be conducted to see how cannabis use effects diminish over time and variables such as severity of use and how that affects driving.
Take Away: The current study looks at variability in vehicle control among young adult drivers who use cannabis compared to young adult drivers who do not use cannabis. Data was used from studies completed at the National Advance Driving Simulator. The final group analyzed included 12 participants in the cannabis user group and 18 nonusers. The driving analysis simulated a driving scenario 35-40 minutes in length with urban, interstate, and rural conditions. The results showed that cannabis users have a more passive engagement when driving and may experience deficits in underlying executive control faculties. Further research should be conducted to see how cannabis use effects diminish over time and variables such as severity of use and how that affects driving.