People Against Drink/Drug Driving

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Cannabis use is a risk factor for motor vehicle crash (MVC) fatalities, but the degree of a driver’s intoxication varies by tetrahydrocannabinol (THC) level. However, cannabis testing does not assess THC levels in most US states, and testing rates among MVC decedents vary among states and over time, which may bias estimates of cannabis involvement. Researchers assessed cannabis involvement and THC levels among fatally injured drivers in Washington State before and after the legalization of non-medical (“recreational”) cannabis use, with and without imputation of missing cannabis testing data among the roughly half of decedents who were not tested.

• Using data from all MVC decedent drivers based on observed and imputed values, the prevalence of cannabis involvement in MVC fatalities was 9% prior to legalization and 19% after.
• In adjusted analyses, the proportion of decedent drivers with high THC levels (>10 ng/mL) increased nearly 5-fold after legalization.
• Although cannabis testing rates increased during the study period, findings were generally similar when restricted to those with completed cannabis testing.

Comments: This study is one of the first to impute cannabis involvement in MVC fatalities among decedents without testing, and to measure and impute THC levels (rather than simply the presence or absence of THC). Legalization of non-medical cannabis use in Washington State was associated with increases in cannabis involvement in MVC fatalities, including at levels clearly associated with impairment. These results add to literature suggesting that legalizing cannabis may increase MVC fatalities, and highlights the need to better characterize and mitigate those risks.

Timothy S. Naimi, MD, MPH

Reference: Tefft B, Arnold LS. Estimating cannabis involvement in fatal crashes in Washington State before and after recreational cannabis legalization using multiple imputation of missing values. 

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Also See 

Drug-impaired driving jumped 43% in first full year after Canada legalized cannabis

New Statistics Canada data shows the number of police charges for drug-impaired driving jumped 43% after Parliament legalized marijuana. “Drug-impaired driving is significantly under detected,” Canada, according to Blacklock’s Reporter. “Drugs may be involved as often, or maybe more often, than alcohol in impaired driving incidents.”

“Unlike drinking and driving charges that peak in twilight hours, the rate of drug-impaired driving varies little from one time of day to another,” said the report.

“Police reported just as many of these incidents between 11 a.m. and 3 p.m., as between 11 p.m. and 3 a.m.,” wrote analysts. For complete story Toronto Sun July 2021 

• Australian cars will be fitted out with sensors that can 'sniff' out alcohol levels
• The sensors measure carbon dioxide and alcohol molecules in drivers' breath
• If the sensor detects alcohol levels over the legal amount the car will not move
• Experts say the new game-changing technology will save thousands of lives 

By OLIVIA DAY FOR DAILY MAIL AUSTRALIA 11 October 2021 

Australian cars will soon be fitted with sensors that can 'sniff' out alcohol, with experts saying the revolutionary technology could save thousands of lives. 

The technology behind the 'ultimate breath test' can detect a driver's blood alcohol level in less than one second using their exhaled breath. 

The sensors use infrared light beams to measure the amount of carbon dioxide and alcohol molecules in the air inside the car. 

For complete story

Your phone can tell when you're high: Data from accelerometer and GPS sensors can be used to predict with 90% accuracy if someone is stoned, study finds

• An algorithm based on sensors data combined with the time of day and day of the week was right nine out of ten times
• The most important features were sensors tracking movements, GPS location 
• Current marijuana tests have a three-day window and are difficult to administer in the field
• The algorithm could 'deliver a brief intervention when and where it might have the most impact to reduce cannabis-related harm' 

By DAN AVERY FOR DAILYMAIL.COM PUBLISHED: 30 September 2021

Sensors on a person's smartphone can be used to determine if they're high with uncanny precision, according to a new study out of Rutgers University

Researchers at the school's Institute for Health, Health Care Policy and Aging Research found that an algorithm that combined sensors tracking movements and GPS location with data on the time of day and day of the week had a 90 percent accuracy rate in determining if someone was stoned.

The algorithm could help law enforcement and health professionals more accurately predict if an individual is currently experiencing 'cannabis intoxication,' according to a release.

'We might be able to detect when a person might be experiencing cannabis intoxication and deliver a brief intervention when and where it might have the most impact to reduce cannabis-related harm,' said co-author Tammy Chung, director of the Institute's Center for Population Behavioral Health in the statement. 

Researchers have been able to create an algorithm that predicts whether a regular pot smoker is high with 90 percent accuracy. The system combines GPS and movement data from their smartphone with info on the time of day and day of the week

The study, published in the journal Drug and Alcohol Dependence, evaluated the feasibility of using smartphone sensor data to identify episodes of 'cannabis intoxication' — being noticeably high— in a non-lab environment.

Just based on the time of day and day of week, the algorithm had a 60 percent accuracy rate

Getting high has been linked to slower response times, which can impair driving and other focus-intensive activities.

Existing marijuana detection measures — like blood and urine tests — present logistical issues and would be too time-consuming to use as an intervention.

In addition, such tests can return positive results for up to three days after a subject has last used marijuana and would no longer be considered high.

As more states legalize marijuana, a smartphone app could be used to determine acute cannabis intoxication, rather than just general usage. 

The authors of the study, who include faculty from Stevens Institute of Technology, Stanford University, Carnegie Mellon University, University of Tokyo and the University of Washington say future research should investigate how algorithms like theirs would rate in classifying people who use weed less frequently.

Most current marijuana tests can return positive results for up to three days after a subject has last used pot. The algorithm could help 'detect when a person might be experiencing cannabis intoxication and deliver a brief intervention when and where it might have the most impact,' researchers say

For complete article

17^th September 2021

Belgium is looking into whether it can prohibit navigation apps such as Waze and Coyote from showing where alcohol and drug controls are set up, after France announced it would ban the practice from 1 November.

Drivers using navigation apps such as Waze or Coyote can, as soon as they notice a traffic jam, indicate via the app where exactly it is. The app then alerts other users so they can avoid the route.

However, this is also the case with police checks, which has raised some ethical questions, as it allows drivers who are under the influence to choose an alternative route.

The French government now wants to counter this practice and will require the apps to block certain messages and notifications for several hours. This will apply to alcohol and drugs checks, or when the police are looking for a fugitive, for example, but not to speed checks.

Federal Mobility Minister Georges Gilkinet is investigating whether a ban could also be introduced in Belgium and has ordered a study on this by the traffic institute Vias.

“Hopefully politicians will follow our recommendation and warnings like these will no longer be issued,” Vias spokesperson Stef Willems said on Flemish radio on Friday, adding that the institute has been in favour of such a ban for a long time.

“That is not only to do with road safety, but it is also about someone who is not insured, and so on,” Willems said. “If everyone starts continuously warning each other about such checks, then it is just those kinds of people who are going to get away.”

For complete story