With the nation slowly relaxing its view on marijuana, many believe that the number of driving under the influence (DUI) arrests related to marijuana will steadily begin to rise.

No Limit in California

Unlike some states where marijuana has been legalized in one form or another (currently, only medical marijuana is legal in California), there is no law on the books in California that places a limit on the amount of THC (tetrahydrocannabinol – the active ingredient in marijuana) that a driver is allowed to have in his or her system before the presence of the substance is considered illegal for the safe operation of a motor vehicle. For example, the law places a limit of .08% on alcohol, which means that anyone found in operation of a motor vehicle with a blood alcohol content of .08% or higher can be arrested and charged with driving under the influence – but no limit of this sort has been set in California for THC.

Instead of following a set limit, California law can find a person guilty of driving under the influence of marijuana (or any other narcotic) if the person is unable to operate a motor vehicle with the same amount of care and caution as someone who is sober. This is both good and bad for drivers. On the one hand, a person with marijuana in his or her system may be able to avoid driving under the influence charges if that person can show that the drug did not impair his or her ability to safely operate a motor vehicle.

On the other hand, this allows the police to help the prosecution secure a conviction if the police offer testimony that shows the individual was, in fact, unable to operate a vehicle safely. This can be shown by the officer’s testimony that the driver was swerving in traffic, was following other vehicles too close, failed to stop at a stop sign or red light, etc. Essentially, any error committed on the road can be used as evidence of impairment when a person is discovered to have been operating a vehicle with marijuana in his or her system.

Chemical Testing

California law also makes it mandatory for anyone who is suspected of driving under the influence of alcohol or drugs to submit to chemical testing. Failure to submit to chemical testing is a violation under California’s implied consent laws, and is generally not the best decision that a person suspected of DUI can make. In most cases, it is better to submit to a blood or urine test (the presence of drugs cannot be detected by breath tests), than it is to refuse testing.

Just because a person submits to chemical testing, however, it does not mean that the person has no hope of avoiding serious consequences. While submitting to a chemical test, the DUI suspect is advised to exercise his or her right to remain silent as early as possible. The sooner this right is exercised, the sooner the DUI suspect will be afforded the full protections of the fifth amendment, which would allow the suspect’s silence not to be used against him or her in court. Simply standing silent, as of a recent Supreme Court ruling, is no longer enough to grant a person full 5th amendment protections against self incrimination.