Injuries/Violence
Polysubstance Use and Involvement of Fatal Motor Carrier Crashes Stanford Chihuri* Stanford Chihuri
Motor carrier drivers play a crucial role in commerce and daily supply chain logistics, often facing high-risk conditions such as long hours, fatigue, and, in some cases, substance use as a coping mechanism. Despite stringent regulations, including mandated lower alcohol impairment thresholds and random drug testing, substance use may still contribute to motor carrier involvement in fatal crashes. However, the role of polysubstance use in these crashes remains underexplored. Using data from the Fatality Analysis Reporting System during 2007–2022, we assessed the association between polysubstance use (Blood Alcohol Concentration ≥0.01 g/dL and positive for any nonalcohol drug) and the risk of fatal crash involvement in motor carrier drivers. The study included 6,675 motor carrier drivers and 7,113 non–motor-carrier drivers involved in 6,393 fatal multivehicle crashes, with available toxicological testing data. Using McNemar’s test to assess drivers involved in the same crashes, non-motor carrier drivers were significantly more likely than motor carrier drivers to test positive for any nonalcohol drug (29.0% vs. 6.4%, χ²=920.94, P<0.0001), alcohol (15.8% vs. 1.0%, χ²=832.69, P<0.0001), and a combination of both (6.8% vs. 0.3%, χ²=381.87, P<0.0001). Conditional logistic regression revealed that motor carrier drivers had 53% lower odds of testing positive for any nonalcohol drug (odds ratio (OR) = 0.47, 95% confidence interval (CI) = [0.33, 0.68]), 83% lower odds for alcohol (OR = 0.17, 95% CI = [0.09, 0.33]), and 98% lower odds for polysubstance use (OR = 0.03, 95% CI = [0.003, 0.23]), after adjusting for age, sex, history of driving while intoxicated, previous accidents, speeding, and survival status. These findings highlight that, despite increasing drug use among the general driver population, motor carrier drivers have a significantly lower risk for drug-related fatal crashes, likely due to effective mandatory and random testing programs.