After many decades of being classified as an illegal commodity, America is gradually loosening the strings on the use of marijuana for medical and recreational use. Currently, as many as 33 states as well as D.C. have made the use of medical marijuana legal while 11 states and D.C. have also legalized recreational marijuana. Motorists are also afraid that car insurance rates will increase if the insurance companies think that the chances of auto accidents due to the free use of narcotics like marijuana will increase accident claims.

Estimating Driving Impairment – Alcohol vs. Marijuana

There is no doubt that by reducing incidences of impaired driving, there will be fewer car accidents, resulting in personal injury, death, and property damage. While the procedures for proving that the driver is under the influence due to alcohol are established, it is relatively difficult for law enforcement to prove influence due to weed. This will not only render law enforcement ineffective in prosecuting THC-impaired driving but also expose drivers to the chance of being prosecuted unfairly.

Unlike alcohol, it is very difficult to estimate how much THC enters the body of someone smoking pot as it depends on how it is consumed and the way it is prepared for consumption. The wearing off of the effect of THC is also not as predictable as that of alcohol. The situation is further complicated by the fact that THC can enter your system just by passively inhaling marijuana smoke while you need to consume alcohol directly. Most tellingly, the amount of THC in the blood is not a good indicator of the extent of impairment and on top of that, it tends to remain in the blood for relatively long periods, unlike alcohol that breaks down very fast. Again, unlike field tests for alcohol impairment, there are no established tests for THC influence.

No Consensus on Whether CBD Causes Impaired Driving

According to Washingtonpost, a study of the insurance claims of car accidents by the Insurance Institute for Highway Safety found that there was a 3% greater chance of accidents in the states that had legalized marijuana. However, another study in the American Journal of Public Health found no such correlation between the use of recreational marijuana and car crash fatalities. In fact, according to i49as well as other sources there does not seem to be any proven clinical evidence that there is any negative effect on driving skills due to the effect of CBD. Advocates of recreational marijuana say that the THC concentration level of the CBD products on sale in America is very low and cannot cause any intoxication. This view gets more credence because a large case-control study by the National Highway Traffic Safety Administration did not find cannabis to be a significant risk for auto accidents.


Even though auto insurers would like everyone to believe that the use of marijuana leads to more accidents, at present, the connection, if any, is extremely tenuous, and extensive research is still being conducted. Due to the fluid nature of the situation, it is important that drivers drive safely and not get involved in DUI cases because it is very likely convictions would have a significant impact on their premiums.