The "High Alert" smartphone intervention was well received by young cannabis users and showed preliminary efficacy in reducing driving after cannabis co-use, though recruitment barriers and high attrition posed challenges.
Digital health researchers, public health practitioners, and substance use intervention developers focused on impaired driving prevention.
Preliminary efficacy for reducing co-use driving
What the researchers found
High Alert, a digital smartphone intervention for youth DUIC, was positively received by participants and showed preliminary efficacy in reducing driving after cannabis co-use compared to a no-contact control. However, implementation challenges including online bot activity, recruitment barriers, and high attrition rates were significant.
Why it matters
Cannabis-impaired driving among youth is a growing concern in jurisdictions with legalized cannabis. Digital interventions are scalable, but this study highlights the practical challenges of deploying them to high-risk young populations.
The numbers in context
Most participants were willing to engage with the app and recommend it to peers. Content and delivery ratings exceeded those of static infographics. Preliminary efficacy was shown for reducing driving after cannabis co-use vs. no-contact group.
How the study worked
Pilot randomized controlled trial comparing High Alert (smartphone intervention) to an active control (DUIC infographics) and a passive control (no contact), evaluated using the six-step Intervention Mapping framework including formative, process, outcome, and acceptability evaluations.
What this study cannot tell us
Pilot study with small sample size. High attrition limits generalizability. Bot activity during online recruitment complicated data quality. Active control group may have also received benefit from infographic exposure.
How to read the evidence
Pilot RCT with small sample, high attrition, and implementation challenges. Provides proof of concept but not definitive efficacy evidence.
When this study was published
2025 publication
The bigger picture
This study demonstrates both the potential and the pitfalls of digital health interventions for substance-related driving behaviors. The recruitment and retention challenges reported are common across digital intervention research with young adults.
Questions still open
- Can High Alert be scaled effectively given the recruitment and retention challenges? Would combining the app with in-person touchpoints improve engagement?
Common questions
What is High Alert?
Did the app actually reduce cannabis-impaired driving?
Read the original research
Using intervention mapping to evaluate 'High-Alert,' a brief smartphone intervention to reduce youth cannabis-impaired driving.
PloS one, 20(8), e0329383
Citation
Colonna, Robert; Tucker, Patricia; Mandich, Angela; Alvarez, Liliana. (2025). Using intervention mapping to evaluate 'High-Alert,' a brief smartphone intervention to reduce youth cannabis-impaired driving.. PloS one, 20(8), e0329383. https://doi.org/10.1371/journal.pone.0329383