How Can Police Tell if Your Driving High

Title: How Can Police Tell if You’re Driving High?


With the increasing prevalence of marijuana legalization and decriminalization across the globe, concerns about impaired driving have become a subject of great importance. Just as driving under the influence of alcohol is illegal, driving while impaired by drugs, including marijuana, is also a significant offense. Law enforcement agencies are constantly seeking innovative ways to identify drivers under the influence of cannabis, ensuring public safety on the roads. This article aims to shed light on methods employed by the police to determine if a driver is driving high and provides answers to frequently asked questions regarding this issue.

Methods Used by Police to Detect Cannabis Impairment:

1. Observational Clues:
Police officers are trained to observe certain behavioral and physical cues that may indicate marijuana impairment. These can include bloodshot eyes, slowed reaction time, impaired coordination, and a distinct odor of cannabis coming from the vehicle or driver.

2. Standardized Field Sobriety Tests (SFSTs):
Similar to alcohol impairment tests, SFSTs are commonly used to evaluate a driver’s physical and cognitive abilities. These tests involve assessing the driver’s balance, coordination, and response to instructions. However, SFSTs alone cannot conclusively determine marijuana impairment.

3. Drug Recognition Experts (DREs):
DREs are specially trained officers who undergo extensive training to identify signs of drug impairment in drivers. They use a 12-step evaluation process, which includes an interview, physical examination, and additional tests to determine if a driver is under the influence of drugs, including cannabis.

4. Chemical Tests:
Chemical tests, such as blood, urine, and saliva tests, can detect the presence of THC (the psychoactive compound in marijuana) in a driver’s system. However, these tests only confirm the presence of THC and not necessarily impairment at the time of testing.

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Frequently Asked Questions (FAQs):

Q1: Can I refuse to take a field sobriety test if I’m suspected of driving high?
A1: While you have the right to refuse a field sobriety test, it may lead to legal consequences, such as license suspension or arrest. Refusing a test can be seen as an admission of guilt, providing grounds for further investigation.

Q2: Can I be charged with driving under the influence of marijuana even if I have a medical marijuana card?
A2: Yes, having a medical marijuana card does not exempt you from impaired driving laws. It is essential to understand the laws and regulations in your jurisdiction regarding marijuana use while operating a vehicle.

Q3: How long does marijuana impairment last?
A3: The duration of marijuana impairment varies depending on factors such as consumption method, dosage, and individual tolerance. THC can remain in the body for several hours or even days, but impairment usually lasts for a shorter period, typically a few hours.

Q4: Can a police dog detect marijuana in my car during a traffic stop?
A4: Yes, trained police dogs can detect the presence of marijuana and other drugs in a vehicle. If a dog alerts to the presence of drugs, it may provide probable cause for a search without a warrant.

Q5: What are the legal consequences for driving high?
A5: The penalties for driving under the influence of marijuana vary depending on jurisdiction. They can include fines, license suspension, mandatory drug education programs, and even imprisonment, particularly in cases involving injury or death.


Police officers utilize a combination of observational clues, standardized field sobriety tests, drug recognition experts, and chemical tests to determine if a driver is impaired by marijuana. While each method has its limitations, the collective efforts of law enforcement aim to curb impaired driving and ensure road safety for all. It is crucial to be aware of and abide by the laws in your jurisdiction to avoid legal consequences associated with driving under the influence of marijuana.

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