Evidence in CA drugged driving cases often limited or questionable

Evidence against people charged with DUID is often limited, since state law establishes no legal limit and testimony from arresting officers is subjective.

Torrance residents who take prescription drugs or use medical marijuana often understand the cognitive side effects and do their best to avoid driving while impaired. Still, even drivers who try to be conscientious may be at risk for criminal charges and penalties. Fortunately, in many cases, drivers may be able to challenge charges of driving under the influence of drugs because of the relative lack of objective or meaningful evidence in California DUID cases.

Officer testimony

California has not set a legal level of impairment for any prescriptions or illicit drugs, according to NBC News. This means DUID charges often rely on the testimony of officers who have been trained as Drug Recognition Experts.

These officers use observations and specialized field sobriety tests to identify impaired drivers. Although officers must successfully complete field testing with people who have used impairing substances to earn their titles, their observations and sobriety tests are far from foolproof forms of evidence. Additionally, according to Los Angeles Weekly, a large number of officers still have not completed DRE training.

Chemical testing issues

Chemical testing can also act as evidence in a DUID case, as it can establish that the driver actually used prescription or illicit drugs. However, the presence of drugs or even the amount measured does not provide compelling evidence of impairment.

A 2010 article posted on the National Institutes of Health website highlights some issues with using chemical tests to judge impairment from drugs. The review focuses on the differences between impairment due to marijuana and alcohol, but it also points to broader issues with establishing the impairment level of a driver who has used drugs recently:

  • The body does not process every substance like alcohol - compared to blood-alcohol content, levels of the psychoactive component of marijuana, THC, peak in the blood quickly after inhalation, then fall rapidly. Accurately measuring the amount of the substance in a driver's blood at the time of a traffic stop or accident can be challenging.
  • Even the most accurate measurements may not be inherently meaningful - different drivers show different levels of impairment at comparable levels of blood-THC content, due to factors such as tolerance.
  • Real-world culpability studies do not lend support to a clear threshold comparable to the BAC limit - studies yield remarkably different findings on the relationship between blood-THC level and accident risk.

Several other substances may present similar issues, since the pharmacology of each substance is distinct. People facing DUID charges may benefit from calling attention to these limitations in the evidence supporting the charge.

Help for DUID charges

Statistics suggest that many drivers in California may be at risk for DUID charges. A 2012 roadside survey from the state's Office of Traffic Safety found that more drivers tested positive for drugs than alcohol; 14 percent of drivers had drugs that could impair driving in their systems. The number of drivers who tested positive for marijuana alone narrowly outstripped the number of drivers who tested positive for alcohol.

Los Angeles Weekly notes that many DUID charges are dropped because of the difficulty prosecutors face in proving that a driver really was impaired. Still, anyone facing these charges should not take chances. Instead, it is best to meet with a criminal defense attorney as soon as possible to discuss the circumstances of the arrest and the best way of challenging the charge.

Keywords: drug, driving, arrest, DUI