How Do The Police Detect Marijuana DWI?

Marijuana is one of the most commonly used illegal substances. It is also one of the most common substances involved in DWI cases. Let’s discuss how the police discover and prove a driver is intoxicated by marijuana.

Signs of Marijuana Intoxication

How Do The Police Detect Marijuana DWI?Marijuana and alcohol generally affect the body differently, but share some similarities.

If an individual is under the influence of marijuana, they may experience:

  • Delayed reaction time
  • Red eyes
  • Rapid heart rate
  • Poor coordination
  • Increased appetite

Some of these effects may be visible to officers during a DWI stop. If they see the driver has bloodshot eyes, appears sluggish, or otherwise seems to be intoxicated, they may begin investigating the driver for potential marijuana DWI.


Marijuana has a strong scent. The odor of marijuana coming from inside the driver’s vehicle may also draw suspicion. It’s important to know that the smell of marijuana coming from a vehicle gives the police probable cause to conduct a search without the driver’s consent. This could result in drug possession and paraphernalia charges, in addition to a marijuana DWI charge.

Tests for Marijuana DWI

There is no breath test equivalent for marijuana DWI. Instead, police officers use other sobriety tests to collect evidence of marijuana intoxication.

  • Blood tests: The driver may be subject to a blood test. The blood test can show the presence of THC. However, it’s important to note that THC can remain in someone’s blood for about two days. This means that if the driver smoked or consumed cannabis at all within the past 48 hours, it could show on the test.
  • Urine tests: Like blood tests, urine tests may show THC in one’s system for up to a month after smoking, depending on that person’s cannabis habits.
  • Field sobriety tests: These tests may be conducted to show the driver’s lack of coordination, balance, or bodily control due to marijuana intoxication.

Marijuana and Drug DWI Defense in Texas

If you are facing charges for DWI of drugs in Texas, contact our attorneys at Deandra Grant Law. We have the knowledge and experience needed to defend you throughout your case. Discuss the details of your arrest and charges with our team today: call (214) 225-7117.

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