Successfully Handling DUI Cases in Los Angeles for 19 Years . Call Us Now at 213-479-5322

Blog Archive

CHP Officer at DUI Marijauna StopDUI Marijuana and You

As smoking marijuana is now legal, at least with a doctor’s recommendation, and at least as far as California law is considered, there has been an increase in charges of DUI Marijuana.  The problem with DUI marijuana is that the tests used to determine the presence of marijuana in a person’s blood/urine are inaccurate.

DUI Marijuana is easy to charge but hard to prove.

First, these prosecutions for DUI marijuana are problematic because NO scientific literature has shown that marijuana impairs a person’s ability to drive.  The results of crash fault studies fail to show that drivers with marijuana in their system are significantly more likely than drug-free drivers to be at fault in crashes.

The active ingredient in marijuana (THC or delta-9-tetrohydrocannibinal) is metabolized to 11-Hydroxy-THC or THC-OH (which is psychoactive) which can be detected in the blood, but not the urine.  THC-OH is quickly metabolized to 11-nor-9-carboxy-THC or THC-COOH (non-psychoactive).

According to research, the level of THC rises to 150 ng/ml instantly after use, it then decreases to 15 ng/ml after 1 hour and 5 ng/ml at 2 hours.  The THC quickly dissipates and by the time the blood is tested (after the stop, initial investigation and DRE, transport to station or hospital for blood draw) the THC is low even if the person had smoked just before driving. THC can remain at low levels for 8 hours without any measurable sign of impairment. Journal of Anal. Tox. Vol. 32: 160-164 (2008).

As with all blood tests, there are two problems: (1) a single blood test cannot predict concentration at the time of driving, the only thing that can do that is a blood test AT the time of driving; and (2) even drug concentrations at the time of driving can never predict whether a person was impaired by drugs because of the wide responses to a drug.  This is a pharmacological truth and cannot be changed by crime lab personnel to obtain a criminal conviction.

Even NHTSA recognizes difficulty of DUI marijuana prosecutions.  In their Drug and Human Performance Fact Sheets, they state that it is difficult to establish a relationship between a person’s THC level in blood and performance impairing effect. They acknowledge that “It is inadvisable to try and predict effects based on blood THC concentrations alone, and currently impossible to predict specific effects based on THC-COOH levels.”

So if you’ve been accused of DUI marijuana, it is easy to fight and win when you know the science of drug use and testing.

My article on DUI Drugs in general is here.

My article on preliminary drug testing is here.

If you have questions about DUI marijuana call me at (213) 479-5322. If you have an opinion, leave a comment.

DUI Drugs Booking FormDUI Drugs CA: Easy to Charge, Hard to Prove

More arrests are being made for DUI drugs than ever before.  While it’s always been illegal to drive while under the influence of drugs, the legalization of marijuana, ready availability of other illicit drugs and proliferation of prescription medications has increased the number of arrests and prosecutions of people for driving while their ability to drive is impaired by drugs.

The way a DUI Drugs arrest usually happens is that a cop observes something that he feels is indicative of being under the influence.  He then pulls the person over, runs them through the field sobriety tests (see here for an explanation why the FSEs are bunk). He then does a preliminary alcohol screening test and it comes up negative or below the legal limit for alcohol. The cop then calls in a different cop with training in a different level/kind of voodoo called a Drug Recognition Evaluater (DRE).

That cop then runs through a 12 step protocol (irony alert) to determine if the person’s ability to drive is impaired by drugs. One of the things they are taught to look for is a green tongue as evidence that the person has smoked marijuana.  This is ludicrous.

As part of the DUI Drugs screening, the cop asks the person to identify all the drugs they take, legal and illegal.  Most people want to cooperate with cops (this is always a mistake — remember: unless you are a lost six year old, that cop is NOT there to help you!) because they think that will get them on their way.  The person admits to using some drug, often thinking that if they admit to the drug they are legally taking, they will be released.

At the end of the DUI Drugs evaluation, the evaluation cop makes a guess about what drug the person is under the influence of (mostly based on what the person tells them) and sends their blood out to be tested. The case is prosecuted as a DUI Drugs case.  The blood test comes back and shows the person has a drug in their system or doesn’t.

These DUI Drug cases are insidious because they are so easy to charge.  The drug the person has in their system doesn’t have to be illegal and since a majority of people use prescription drugs to manage some problem and all these drugs have some side effect, the cop can easily make an arrest. The cops take two mostly unrelated events: admission to drug use and failure on their Drug DUI evaluation to correlate that the person’s supposed impairment (based on the cop’s observation of ‘poor’ driving) is caused by drugs.

The problem is that science tells us that you can’t determine whether a person is impaired by drugs by the fact that they have a certain drug in their system.  First, drugs remain in the blood a long time after they have any effect on one’s ability to drive.  So presence in the blood doesn’t mean the drug is still acting on the body.

Second, and most importantly, everyone who uses a drug — prescription or other — develops a tolerance to the drug.  That tolerance is unique to the individual and can’t be predicted.  The person who uses a drug over a period of times adapts to it’s presence in the body. So use of a drug, doesn’t predict that the person was impaired by the drug.

This means that DUI Drugs prosecutions are difficult if not impossible to convict.  The State’s lab tech has to admit that he can’t tell by the presence of a drug that the person was impaired by the drug. The prosecutor then has to rely on the obviously biased testimony of the DRE cop to say that the person’s behavior was due to being under the influence of whatever drug the blood test showed.  This can be a different drug than the one they guessed during their evaluation.  The problem with this scientifically and logically is that it’s confusing correlation (the presence of two variables) with causation (one variable [drugs in the body] caused the other [subjective failure of the DRE]).  There is also the problem present in all DUI prosecutions that failure on subjectively evaluated tests means impaired ability to drive.

See my article about DUI and marijuana here.

See my article about the DUI Drug Test in CA here.

If you have any questions about DUI Drugs, impairment by drugs, or other DUI or drug related topics, call me at (213) 479-5322. If you have an opinion, leave a comment.

The DUI Drug Test At DUI Checkpoints in California: Don’t Do it.DUI Drug Test machine on CHP Car

Portable drug tests at DUI Checkpoints are the LAPD’s new way to invade your privacy while you’re a guest at one of their numerous checkpoints (LA and other counties have hundreds of thousands of dollars of checkpoint grant money they need to spend).

The test purports to be able to tell if the subject has amphetamines, marijuana, cocaine benzodiazepine (the active ingredient in prescription drugs like Xanax) and other illegal substances.

Before you swab, remember: the only test you HAVE to take when arrested on suspicion of DUI Drugs is a Blood Test after Arrest. (This is based on the Implied Consent laws, not HAVE to take based on Fourth Amendment grounds.) The swab test when administered at the checkpoint is the equivalent of the PAS handheld breath tester given to those suspected of being impaired by alcohol. Because of that, there should be an admonition stating that you are free to refuse to take the test without consequence. But there isn’t.

There should be an admonition read, because you are free to refuse the test. So refuse to take the test if asked.

Once arrested the Supreme Court has said that taking a sample of your DNA is a constitutionally reasonable seizure. However, the law in California doesn’t provide for the admission of these drug swab tests as evidence in a DUI, like a Blood Test would be admitted. Many foundational issues exist with respect to the admission of a new technique like saliva swabbing for drug detection.

The LA City Attorney has yet to use one of these portable drug test swabs in an actual trial.

Check out additional articles on What to do at a DUI Checkpoint and Case Law for DUI Checkpoint Arrests.

If you are going out this weekend, make sure to check here for the location of DUI Checkpoints. If you have questions about checkpoints, DUIs or DUIs with drugs call me at (213) 479-5322 or visit my website at

How Can We Help You?

Your Name (required)

Your Email (required)

Your Phone Number

Your Message / Case Info / Best Time to Call

Your information is 100% Confidential.
Apex Chat

Copyright 2014 The Law Office of Edward J. Blum