How Do California Police Officers Test for Marijuana?

Just as driving drunk is illegal, so is driving under the influence of marijuana. Essentially, any impaired driving can get you into trouble. If you’re pulled over by a police officer who suspects impairment, tests can detect THC if necessary.

While it’s true that recreational marijuana use is legal in many states, including California, it’s still against the law nationwide to operate a motor vehicle while under the influence of drugs or alcohol of any kind.

Thus, law enforcement agencies can legally request that you consent to a weed DUI test. But what are these tests, and how do police officers detect THC? To answer this question and more, we first need to define what it means to drive under the influence of marijuana.

Marijuana Use While Driving

Drivers are affected by marijuana and thus under the influence when consumption causes physical and mental impairment to the point where the driver can no longer safely operate a vehicle. But to determine whether the driver in question is under the influence, a judge or jury will have to decide.

This is because California law doesn’t have a set legal limit for marijuana in one’s system. What’s more, there is much debate surrounding the effects of marijuana while driving. Some proponents argue that cannabis use actually makes you sharper and more aware of your surroundings.

Others, however, claim it to be just as dangerous as drunk driving. If a driver is under the influence of marijuana at the time of arrest, a prosecutor must convince the judge or jury in court.

DUI cases regarding marijuana driving pose a serious challenge to prosecutors. As stated, California doesn’t set limits on how much cannabis a person can have in their system while driving. Thus, prosecutors have to prove that however much a person had present in their body was enough to cause impairment behind the wheel. 

THC vs CBD: Knowing the Difference

THC is short for delta-9-tetrahydrocannabinol and is the primary ingredient in cannabis that causes psychoactive effects. It’s also what makes cannabis users feel “high.” Some weed contains minimal THC content, but the CBD (cannabidiol) content might be high. CBD is a non-psychoactive substance found in hemp. 

In fact, many medical marijuana users choose high CBD strains to get the health benefits of marijuana without the intoxicating effects. This can ensure that they don’t fail a drug test for work, for example.

Chemical Testing: Does It Work?

Chemical testing is available for checking a person’s THC levels. However, these tests are unreliable. To make matters worse, experts disagree on how much THC is safe. As such, this division and unreliability present problems for convicting a driver of a DUI charge.

With that said, the test results from chemical testing aren’t needed for conviction. This is often confusing to drivers in California. But if there is enough evidence elsewhere to show that you were impaired, test results become unnecessary.

Also, it’s important to note that if all the prosecution has is a positive chemical test and there’s no other evidence, the test usually won’t be enough for a conviction. At the end of the day, it often comes down to other forms of evidence that prove you were under the influence and unsafe to drive a motor vehicle.

Other Evidence

So, what are the other forms of evidence that you might need to be worried about? Examine the examples below to better understand the evidence that can result in a DUI conviction.

  • Your driving pattern
  • The statement you gave to the police
  • Your performance in Field Sobriety Tests
  • You had marijuana on you or in your vehicle
  • You had drug paraphernalia on you or in your vehicle
  • There’s evidence that shows you’re addicted to cannabis

Moreover, if there is a Drug Recognition Expert (DRE) at the scene, they will make a note of your appearance and actions. People who are intoxicated will exhibit the following traits:

  • Delayed/slow reaction time
  • The smell of weed
  • Rapid breathing
  • Fast heart rate
  • Dilated pupils
  • Dry mouth
  • Red eyes

Most of the time, when there is suspicion of drug use, the attending officer will call in a DRE to examine the suspect. If the case goes to court, the DRE can testify on the arresting officer’s behalf, thus providing potentially damaging evidence against the suspect.

Testing for Marijuana: How It’s Done

If the officer suspects drug use in a person who chose a breath test, a blood test may be ordered. However, a blood test can only be requested if the officer believes the following: 

  • The driver is under the influence of marijuana or other types of drugs
  • The blood test will show that drugs are present

Moreover, blood tests usually come up in the following scenarios: 

  • The breath test came back negative, or the alcohol content was very low
  • The police officer smells marijuana on the driver
  • The police officer observes physical signs revealing intoxication
  • The police officer found drugs in the driver’s vehicle
  • The police officer found drug paraphernalia in the vehicle

If a blood test is not possible, such as if a medical condition prevents it or a blood test isn’t readily available, a urine screen will be presented instead.

Chemical Tests and Reliability

Using chemical tests to prove that someone is driving under the influence of marijuana has three fundamental problems:

  • There is no consensus on the extent to which cannabis can cause driving problems
  • Chemical tests cannot reliably indicate when someone used marijuana
  • They cannot reliably indicate how much has been used

Test results may also vary based on the type of test used. When you secure the services of a trusted DUI attorney in California, you can look forward to comprehensive research and representation that fights for your rights.

Your lawyer will carefully examine all evidence to make sure that proper protocols are followed at all times. So if you are facing DUI charges, consider getting legal counsel. You will have the guidance and direction you need to ensure that nothing is overlooked in your case.

Blood Testing

The most commonly used chemical test in cannabis DUI cases is a blood test. The blood test directly looks for the presence of THC. But unlike alcohol, the rate of metabolism of THC is not stable, especially when smoking. Conversely, the THC level in the blood can reach a peak in just ten minutes and then drop rapidly.

When someone’s arrested, and blood samples are taken, most of the THC will likely be gone. Furthermore, THC can be detected within one month after smoking marijuana.

But the bigger problem with THC blood testing is that, unlike water-soluble alcohol, THC is fat-soluble. This means that once ingested, it will be stored in the body’s fat tissues.

These fatty tissues can filter stored THC back into the blood for up to a month or more. Therefore, even if the driver has not smoked or used marijuana recently, the THC blood test may be positive. 

In addition, low THC levels in the blood may be due to relatively recent use or long-term use. So even if a person didn’t recently consume cannabis, it could still show up. As such, a positive blood test does not factor in as well as one might think.

Urine Testing

The urine test does not directly check for the presence of THC. Instead, it detects the presence of inactive metabolites found in cannabis. These inactive metabolites can be detected in the urine for a long time after using cannabis. Some estimates indicate that they can be detected in long-term users for up to 4 weeks.

Since these substances do not cause harm by themselves, a positive urine test does not prove that someone is “affected” by marijuana. It only indicates that the person had smoked marijuana at some point in the past month or so.

It’s also worth noting that strains high in CBD can trigger false positives. With so many variables, it’s difficult for prosecutors to paint a clear picture of factual use in a suspect. This is why it’s so important to have a qualified DUI attorney in your corner. 

Your lawyer will focus on the inaccuracies of the testing methods used and fight to prove to the court that you weren’t impaired while driving. Moreover, your attorney will carefully gather evidence and make sure that proper procedures are followed at all times. 

To ensure that you receive the representation you deserve, contact a California DUI attorney today.

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