How Do Police Detect Drivers Under the Influence of Marijuana?

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States around the U.S. are beginning to reconsider their laws criminalizing marijuana. It's important to remember that although smoking marijuana may not be illegal in some parts of the county, driving a vehicle while under the influence of marijuana is still a crime in all 50 states.

Similar to how alcohol's effects on the body make it unsafe for an individual to operate a vehicle, the effects of marijuana on the body and mind also create a dangerous impairment for drivers. Studies indicate that marijuana use can cause drowsiness, lethargy, an altered sense of time, and inhibit people's ability to perform divided-attention tasks.

Police assert that various "tell-tale signs" help them detect drivers under the influence of marijuana:

  • Drivers with bloodshot, watery eyes
  • Drivers having trouble responding in normal amounts of time
  • An odor of marijuana coming from the vehicle
  • Drivers traveling at unusually slow speeds

If police have a reasonable suspicion that a driver has ingested marijuana, they will likely perform a roadside sobriety test—the same test given to those suspected of being under the influence of alcohol or other drugs. If the driver fails the sobriety test, then the officer can either make an arrest or call an ambulance to the scene to conduct a voluntary blood test. This measures THC levels in the driver's blood.

DUI laws regarding drugs and other controlled substances vary from state to state. Pennsylvania has its own "Drugged Driving" laws detailing the penalties for drivers found to be under the influence of marijuana. While personal marijuana use may not be a crime in some regions, this is not the case if someone else's marijuana use puts others at risk.

Have You or a Loved one Been a Victim of a Driver Under the Influence?

If you or a loved one were a victim of a driver under the influence of marijuana or another substance, contact us today for a free legal consultation. There's no obligation to use our services, so you have nothing to lose.

Call 412-394-1000, or fill out the form at the top right of this webpage to get started. Accidents happen around the clock which is why our phones answer 24/7. Contact us at any time to find out if you have a case and learn your legal options.

Sources: “Don’t puff & drive? Expect DUIs for pot in Colorado.” January 3, 2014.