Edible cannabis use on simulated driving performance

Abstract

Objective: To assess driving performance after consuming edible cannabis using a driving simulator, examining frequency of use, THC dose, and rural versus urban settings. Methods: Adults in Denver, Colorado (N = 88), between 25 and 55 years old, were recruited from November 2023 to July 2024 and assigned to groups based on past 90-day cannabis use: daily (N = 29), occasional (N = 30), or no recent use (i.e., comparison group; N = 29). This within-subjects study compared driving performance (i.e., speed, lane departures per minute, and standard deviation of lateral placement (SDLP)) using a validated driving simulator (miniSim™) at baseline and two post-consumption tests (52 and 119 min). Linear mixed models were used to evaluate performance. Results: Daily-use group drove slower than the occasional-use group (decrease in average speed from pretest of 2.49 mph (urban, p < 0.01 post-1); 1.80 mph (p = 0.02 post-2)) and the comparison group (decrease in average speed from pretest of 2.70 mph (urban, p < 0.01 post-1); 2.68 mph (urban, p < 0.01 post-2)). Lane departures increased in the occasional-use group from 0.17 at pretest to 0.47 in post-1 and 0.40 in post-2 (p < 0.01). Their rural SDLP increased: post-1 (29.37 cm, p < 0.01), post-2 (29.81 cm, p < 0.01), versus pretest (25.45 cm). This group had significantly greater change in lane departures than both the comparison group (0.26, p < 0.01) and daily-use group (0.34, p < 0.01) in post-1. In post-2, the change remained greater than the daily-use group (0.20, p = 0.02). Conclusion: Our study found significant changes in driving performance following edible cannabis use, including findings related to effect duration, use frequency, and road settings. The occasional-use group showed greater impairment than daily-use group, suggesting tolerance contributes to outcomes beyond THC concentration alone.