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Study breakdown

What interventions actually work to prevent drugged driving?

Systematic ReviewModerate evidence
The takeaway

A systematic review of 28 studies found that cannabis packaging warnings, roadside drug testing, and motivational interviewing showed the strongest evidence for preventing drugged driving, while state-level legal sanctions showed little effect on drug-related fatalities.

Policymakers designing drugged driving prevention programs, public health officials in legal cannabis jurisdictions, and researchers studying traffic safety interventions.

Legal sanctions: little effect on fatalities

What the researchers found

Cannabis packaging with health warnings increases knowledge about drugged driving effects (high certainty). Roadside drug testing can reduce drugged driving among cannabis users (moderate certainty). For youth, motivational interviewing can prevent drugged driving and driver education increases knowledge (moderate certainty). State sanctions, including criminalization and per-se laws, showed little or no effect on drug-related fatalities (very low to low certainty).

Why it matters

As cannabis legalization expands, preventing drugged driving becomes urgent. This review reveals that punitive legal approaches may be the least effective strategy, while information-based and behavioral interventions show more promise.

The numbers in context

11 RCTs + 17 nonrandomized studies; 33,711 youth participants; packaging warnings: high certainty; roadside testing: moderate certainty; motivational interviewing: moderate certainty; legal sanctions: very low to low certainty

How the study worked

Systematic review searching MEDLINE, PsycINFO, Web of Science, Embase, and other databases through May 2020. Included 11 RCTs and 17 nonrandomized studies (predominantly youth aged 15-25, n=33,711). Evidence certainty rated using GRADE guidelines.

What this study cannot tell us

Most studies focused on youth; applicability to older adults unclear. Heterogeneous interventions and outcome measures. Limited evidence on actual crash and fatality outcomes. Most studies measured knowledge and attitudes rather than behavior change.

How to read the evidence

Systematic review with GRADE certainty ratings. Evidence strength varied by intervention type, with the strongest evidence for packaging warnings.

When this study was published

Published in 2021; drugged driving prevention research is rapidly evolving with cannabis legalization.

The bigger picture

The finding that legal sanctions have little impact on drug-related fatalities is striking and challenges the assumption that tougher laws automatically improve road safety. Education, testing, and behavioral interventions appear more effective, suggesting a public health rather than criminal justice approach may be warranted.

Questions still open

  • Why do legal sanctions fail to reduce drug-related fatalities? Would combining interventions (e.g., roadside testing with education) be more effective than single approaches? How can motivational interviewing be scaled for broader populations?

Common questions

Do tough laws prevent drugged driving?
This review found very low to low certainty evidence that legal sanctions, including criminalization and per-se THC limits, have little or no effect on drug-related fatalities or injuries.
What actually works?
The strongest evidence supports cannabis packaging with health warnings (high certainty), roadside drug testing (moderate certainty), and motivational interviewing for youth (moderate certainty).

Read the original research

Interventions to Prevent Drugged Driving: A Systematic Review.

American journal of preventive medicine, 61(2), 267-280

Citation

Razaghizad, Amir; Windle, Sarah B; Gore, Genevieve; Benedetti, Andrea; Ells, Carolyn; Grad, Roland; Filion, Kristian B; Eisenberg, Mark J. (2021). Interventions to Prevent Drugged Driving: A Systematic Review.. American journal of preventive medicine, 61(2), 267-280. https://doi.org/10.1016/j.amepre.2021.03.012

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