Cannabis effects on driving lateral control with and without alcohol

- We model cannabis' effects on driving lateral control via sophisticated simulator.
- Models are based on blood THC and breath alcohol concentrations during driving.
- THC increased standard deviation of lateral position (SDLP); 0.26 cm per μg/L THC.
- Alcohol increased SDLP 0.42 cm per 0.01 g/210 L; additional lateral control measures.
- During-drive 7-10 μg/L blood THC produced similar SDLP to 0.05 g/210 L breath alcohol.
- Concurrent alcohol and cannabis produced additive rather than synergistic effects.