Several studies in recent years suggest an increase in car accidents following cannabis legalization, but the data typically lacks enough detail to provide a proper analysis. For example, the primary studies do not account for other substances, who was at fault or when the driver smoked cannabis. The latter is key since a person can test positive for cannabis several weeks after consumption. Nevertheless, a new study reconfirms what many others have, namely that driving drunk is significantly more dangerous.
"Cannabis, alcohol and fatal road accidents," published by the PLoS One journal in November 2017, examined details from the Metropolitan France police force that included more than 4,000 drivers involved in car accidents. "Drivers under the influence of alcohol are 17.8 times more likely to be responsible for a fatal accident," the study concluded, while "drivers under the influence of cannabis multiply their risk of being responsible for causing a fatal accident by 1.65." That's an elevenfold difference in terms of who caused the accident. Moreover, the study found that 28 percent of fatal accidents could be prevented if no drivers exceeded the legal alcohol limit compared to four percent for cannabis. The study added, "Alcohol remains the main problem in France."
The researchers also compared their findings to a similar one conducted in France nearly a decade earlier. The study noted, "The overall number of deaths from traffic accidents has dropped sharply during this period, and the number of victims attributable to alcohol and/or cannabis declined proportionally." This is obviously good news, and it highlights the benefits of education-based programs (which increased over the decade) designed to decrease drunk and stoned driving.