Why isn’t there a breathalyzer to detect marijuana?

On Behalf of | Nov 2, 2017 | Blog |

If you have ever been busted for pot possession or driving under its influence, the police probably asked you to give a urine sample. 

Why don’t they use a roadside breath tool like they use for alcohol? Because alcohol is very simple to detect, while marijuana is very complicated from a chemical standpoint.

Chemical complexities

Because of this complexity, tests of blood, saliva, urine and hair have all been used to detect levels of tetrahydrocannabinol (THC). It is difficult to develop a breathalyzer tool that will deal with the complexities of marijuana testing.

Researchers say that marijuana use resists useful detection several ways:

What to test for

  • People may have high levels of THC for different reasons. In California, for instance medical marijuana is perfectly legal.
  • It’s unclear, then, what a marijuana breathalyzer should be testing for – level of the substance or degree of impairment.
  • Marijuana metabolites are easily detected, but they can stay in the body for months after smoking. So a person can score a high number in a test, while being sober.
  • Scientists simply don’t understand the relationship between the levels of marijuana in the human body and its effects on cognition and competence behind the wheel.
  • Detection technologies may show how much THC is in a person, but they can’t show how high you are. People accustomed to marijuana seem to drive quite safely under the influence. People less accustomed get higher and are more likely to cause accidents.
  • In addition, occasional users of marijuana may have very low levels of marijuana in their blood and be high, while frequent smokers may have high levels of marijuana in their blood and be sober or safe behind the wheel.

The technology is coming anyway

Despite these confusions, companies are preparing marijuana breath testing machines, and some are being tested in various locations right now.

Our sense is that these new machines, as they roll out to police departments around the country, will spur an entirely different set of legal defenses for driving under the influence.

As always, Yeretsian Law will be ready to defend you.