Big Valley Law Is Here For You

How do the police know if you are driving while high?

On Behalf of | Jan 5, 2022 | DUI

At this time, there exists no established test to determine if a motorist is too high on marijuana to operate a vehicle safely. However, since recreational weed is now allowed in Virginia, more residents than ever face DUI convictions for drugged driving.

With the lack of accurate testing in mind, how are police officers able to determine when someone is driving under the influence of cannabis? In most situations, officers must rely on their training and experience. As you might imagine, this leaves a lot of room for mistakes and erroneous arrests.

What detection methods can reveal marijuana intoxication?

Most states now employ officers trained to fill the role of a drug recognition expert (DRE). These specialized officers provide expert assistance in determining when a driver is stoned on weed. Some of the methods DRE officers use include:

  • Rule out alcohol first by examining the field sobriety test results
  • Interview the arresting officer for details about the situation and the defendant
  • Examine the defendant physically to rule out injury and detect signs of weed ingestion (eyes, speech, appearance, etc.)
  • Give the defendant a series of psychophysical tests similar to field sobriety tests
  • Take and record the defendant’s vital signs (pulse, blood pressure and temperature)
  • Examine the subject’s pupils under three different lighting conditions with a pupilometer device

The DRE will continue their assessment by speaking with the subject and at least once more taking a pulse reading. When finished, the DRE analyzes the findings and determines whether the defendant was driving under the influence of drugs. The details provided by a DRE can make a big difference in the severity of the DUI charges defendants can face.

We recommend learning more about DUI and drugged driving in the state of Virginia. Knowledge of the law combined with legal counsel can help you avoid the most unfavorable outcome in your case.

Practice Areas


FindLaw Network