Learn why testing positive for marijuana doesn’t automatically prove liability for car accidents

Marijuana Use and Car Accident Liability

Since recreational marijuana use is no longer a criminal offense in California, more and more individuals are using marijuana and then getting behind the wheel. This creates the potential for car accidents because THC, the psychoactive compound in marijuana, can impair a driver’s judgment, coordination, and reaction speed. However, proving that marijuana use caused a car accident can be trickier than you might think, as a recent ruling from the California Court of Appeals shows.

David V Hernandez Will Be a Guidepost Decision

In the case of David v Hernandez et al., the reliability of expert testimony for establishing marijuana impairment came under fire. The decision in this case will serve as a guidepost for attorneys seeking to prove or disprove marijuana impairment in other car accident injury cases.

The case involved a plaintiff, David, who was struck by a tractor trailer. The defendants in the case argued that David should be partially liable for his own injuries because he was allegedly impaired by marijuana at the time of the accident.

By his own admission, David had smoked marijuana within 36 hours of the accident. He also tested positive for THC in a urine test at the hospital after the accident. The defense had an expert witness who concluded from these two facts that David was impaired by marijuana at the time of the accident.

However, the trial court excluded the expert’s testimony because there was insufficient scientific evidence to conclude David was impaired. On appeal, the Court of Appeal agreed with the lower court, finding that the expert’s testimony was speculative because:

  • The concentration of active THC in David’s system was unknown. Only active THC leads to impairment. Active THC leaves the system within hours, while inactive THC can remain for days.
  • The way THC affected David as unknown: The same amount of active THC will affect different individuals in different ways, depending on their metabolism, their history of marijuana use, and other factors. In the absence of any observable signs of impairment, concluding David had enough THC in his system to impair him was pure speculation.

So How Can Marijuana Impairment Be Proven?

In order to establish that a driver was actually impaired by marijuana, it is not enough to prove that that driver had marijuana in their system, or even that they had active THC in their system. Instead, attorneys need to show evidence of impairment, such as erratic driving, physical signs of impairment, or marijuana or marijuana paraphernalia in the vehicle.

What Does This Decision Mean for Your Car Accident Case?

The fact that marijuana impairment is difficult to prove can affect car accident claims in two main ways. First of all, victims should know that testing positive for THC will not necessarily make them liable for their own injuries or impair their ability to receive compensation. However, they must also realize that just because the other driver may have used marijuana does not automatically them liable for the accident. Other steps must be taken to prove liability.

If you need help with a car accident injury case involving marijuana impairment, call The Law Offices of Larry H. Parker at 800-333-0000 now for a free consultation.

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