Drivers with children in the car were less likely to drink but just as likely to test positive for THC

In a Washington State roadside survey, drivers with child passengers were much less likely to have been drinking but equally likely to test positive for THC compared to drivers without children.

Romano, Eduardo et al.·Journal of studies on alcohol and drugs·2019·Moderate EvidenceCross-Sectional
RTHC-02262Cross SectionalModerate Evidence2019RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Cross-Sectional
Evidence
Moderate Evidence
Sample
Not reported

What This Study Found

Drivers with children were less likely to be alcohol positive (0.2% vs. 4.5%, p < .0001) but equally likely to be THC positive (14.1% vs. 17.7%, p = .29). Among drivers who perceived no impairment risk from cannabis, 40.6% of those with a child and 28.9% of those without tested positive for THC.

Key Numbers

2,056 drivers (1,238 male). Alcohol positive with child: 0.2%, without: 4.5%. THC positive with child: 14.1%, without: 17.7%. Among those perceiving no cannabis risk, 40.6% with a child tested THC positive.

How They Did This

Cross-sectional analysis of 2,056 drivers from the Washington State Roadside Survey (2014-2015). Oral fluid, blood, and breath samples collected to measure cannabis and alcohol. Self-reported data assessed risk perceptions.

Why This Research Matters

Adults appear to self-regulate alcohol use when driving with children but do not similarly reduce cannabis use, possibly because they perceive cannabis as less impairing or less risky.

The Bigger Picture

This reveals a public health blind spot: while drunk driving with children has been heavily stigmatized, driving after cannabis use with children has not received the same attention, even in a state where cannabis is legal.

What This Study Doesn't Tell Us

Cross-sectional roadside survey; THC presence does not confirm impairment at the time of driving. Self-reported risk perceptions may not reflect actual behavior. Washington State may not generalize to other jurisdictions.

Questions This Raises

  • ?Would targeted messaging about cannabis-impaired driving with children change behavior?
  • ?Why do risk perceptions for cannabis diverge so sharply from alcohol?
  • ?Are children in THC-positive drivers' cars at measurably higher risk?

Trust & Context

Key Stat:
14.1% of drivers with children tested positive for THC
Evidence Grade:
Moderate: systematic roadside survey with biological testing, but cross-sectional and unable to confirm actual impairment.
Study Age:
Published in 2019.
Original Title:
Use of Alcohol and Cannabis Among Adults Driving Children in Washington State.
Published In:
Journal of studies on alcohol and drugs, 80(2), 196-200 (2019)
Database ID:
RTHC-02262

Evidence Hierarchy

Meta-Analysis / Systematic Review
Randomized Controlled Trial
Cohort / Case-Control
Cross-Sectional / ObservationalSnapshot without intervening
This study
Case Report / Animal Study

A snapshot of a population at one point in time.

What do these levels mean? →

Frequently Asked Questions

Does testing positive for THC mean the driver was impaired?

Not necessarily. THC can remain detectable in biological samples long after effects have worn off. However, the study raises concerns about the frequency of recent cannabis use among drivers transporting children.

Why do drivers treat alcohol and cannabis differently?

Decades of public campaigns have stigmatized drunk driving, especially with children. Cannabis use while driving has not received the same level of public health messaging, and many users perceive it as less impairing.

Read More on RethinkTHC

Cite This Study

RTHC-02262·https://rethinkthc.com/research/RTHC-02262

APA

Romano, Eduardo; Kelley-Baker, Tara; Hoff, Staci; Eichelberger, Angela; Ramírez, Anthony. (2019). Use of Alcohol and Cannabis Among Adults Driving Children in Washington State.. Journal of studies on alcohol and drugs, 80(2), 196-200.

MLA

Romano, Eduardo, et al. "Use of Alcohol and Cannabis Among Adults Driving Children in Washington State.." Journal of studies on alcohol and drugs, 2019.

RethinkTHC

RethinkTHC Research Database. "Use of Alcohol and Cannabis Among Adults Driving Children in..." RTHC-02262. Retrieved from https://rethinkthc.com/research/romano-2019-use-of-alcohol-and

Access the Original Study

Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.

This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.