The drive to legalize the use of marijuana has spread across the country in recent years. At least 38 states have made it lawful to use the substance for medical or recreational purposes, or both.
In the past year, five states had proposals on the ballot to legalize recreational marijuana, with voters approving the expansion in Maryland and Missouri, but rejecting proposals in Arkansas, North Dakota and South Dakota.
But as people use marijuana more frequently and openly, the risks around driving while under the influence grow. And the prospect of more crashes linked to marijuana use also is on the rise.
“As recreational marijuana becomes more widely available, there are concerns about the potential dangers of driving under the influence,” says Pat Aussem, associate vice president of consumer clinical content development at Partnership to End Addiction, a New York nonprofit.
That reality can impact the rates you pay for car insurance.
- 38 states and the District of Columbia allow the use of marijuana for medical purposes.
- States that legalized recreational marijuana saw increased collision claim frequency by 4% from 2012 to 2019.
- Following a DUI, car insurance rates jump by 80% on average and rates tend to jump from an average of $1,447 to $2,610.
- Following a DUI, car insurance rates double on average. The national average cost of a full coverage policy is $2,076 a year, but after a DUI, it’s $4,291.
- How does marijuana affect drivers?
- How is marijuana regulated at the state and federal levels?
- What are per se laws regarding marijuana?
- What are marijuana impairment laws and how are they different from BAC testing?
- Marijuana laws per state: Which states are per se and which are impairment states?
- How will a DUI affect auto insurance rates?
How does marijuana affect drivers?
Marijuana and driving do not mix. According to the National Institute on Drug Abuse, driving under the influence of this substance impairs your:
- Motor coordination
- Reaction time
Having THC – the psychoactive component in marijuana – in your body can reduce your ability to drive a car safely. In fact, marijuana is the illegal drug that shows up most often in the blood of drivers involved in crashes, according to the National Institute of Drug Abuse.
Those with THC in their blood are anywhere from three to seven times more likely to be responsible for a crash than those who drive unimpaired by any substance.
There is evidence of an increase in the accident rate since marijuana was legalized in several states.
An examination by the Highway Loss Data Institute of insurance records found that legalizing retail marijuana sales in four states – Colorado, Nevada, Oregon and Washington – increased collision claim frequency by 4% compared with other Western states from 2012-19.
A separate study conducted by the Insurance Institute for Highway Safety found that the use of recreational marijuana was associated with a 6.5% increase in injury crash rates and a 2.3% increase in fatal crashes from 2009-19.
Aussem says people must understand the risks of driving while under the influence of marijuana. It is imperative to understand how long they should wait before driving after smoking cannabis or consuming edibles.
How is marijuana regulated at the state and federal levels?
Laws related to marijuana use differ sharply between how the federal government views the substance and how various states treat recreational and medicinal use.
The federal view is simple and straightforward: All marijuana use remains prohibited. However, that is often not the case at the state level. How many states have legalized marijuana? In truth, marijuana laws by state vary.
The overwhelming number of states – 38 – allow the use of marijuana for medical purposes. Meanwhile, 21 states and the District of Columbia allow the use of marijuana for recreational purposes.
The Colorado Department of Transportation’s blog says that people who have consumed marijuana should do the following:
- Wait at least six hours after smoking marijuana containing less than 35 mg THC before driving or biking. If you have smoked more than 35 mg, wait longer.
- Wait at least eight hours after eating or drinking marijuana containing less than 18 mg THC before driving or biking. If you have consumed more than 18 mg or if you have consumed alcohol as well, wait even longer.
What are per se laws regarding marijuana?
A per se law prevents people from legally driving if they have specific amounts of a drug in their bodies.
For marijuana, per se laws define impairment as a certain amount of THC in a person’s blood. Aussem says this varies from state to state but is usually between 2 ng/ml to 5 ng/ml.
“There is a tremendous debate as to whether these limits are accurate in reflecting impairment due to the different ways in which people metabolize the drug,” Aussem says.
Currently, 17 states have zero tolerance or non-zero per se laws for marijuana, according to the Governors Highway Safety Association:
- Ten states have zero tolerance for THC (the psychoactive compound that makes people feel “high”) or a metabolite (the molecule into which THC breaks down).
- Three states have zero tolerance for THC but no restriction on metabolites.
- Four states have specific per se limits for THC.
A single state – Colorado – has a permissible inference law for THC.
What are marijuana impairment laws and how are they different from BAC testing?
Unlike per se laws, impairment laws go beyond the substance in your system and focus on driving quality and behavior when you are stopped.
“Impairment laws typically rely on a drug recognition expert to assess an individual for impairment using a 12-step protocol,” Aussem says.
This includes items such as:
- Blood-alcohol content
- A statement from the arresting officer
- A reading of the driver’s pulse
- Examination of the driver’s pupils
- Divided-attention tests
Testing for the presence of THC in your blood can be challenging. And some states use oral fluid testing “to confirm that substances are in a person’s system at the time of the arrest.”
The Insurance Information Institute says there is no equivalent of a “breathalyzer” test for testing impairment from marijuana. While some have suggested that testing saliva may reveal a driver’s THC levels during stops, others say such results cannot accurately indicate a driver’s level of impairment.
The AAA Foundation for Traffic Safety notes that the best way to test a person’s THC levels is to take a blood sample. However, that reality “has practical and constitutional implications for roadside testing.”
In addition, THC metabolizes quickly, so collection typically needs to happen within an hour of the person driving.
Aussem says better testing methods are needed to identify the level of impairment in people who use marijuana and drive. She says statistics about marijuana use and driving accidents can be misleading because finding the presence of cannabis in a driver’s system does not mean the drug played a role in the crash.
“Someone could use cannabis on Friday night and get into an accident on Monday morning,” Aussem says. “THC would still be in the person’s system, but it would not be a reason for impairment in this scenario.”
Marijuana laws per state: Which states are per se and which are impairment states?
Here is a breakdown of which states have per se laws and those that follow an impairment model:
How will a DUI affect auto insurance rates?
A DUI can significantly impact how much you pay for auto insurance. In fact, following a DUI, your can expect your car insurance to double, and stay that way for three years.
The national average cost of a full coverage policy is $2,076 a year. After a DUI, the average cost of car insurance jumps to $4,291.
The Insurance Information Institute notes that if the spread of marijuana use spreads to more states and becomes an increasing factor in accidents, it could cause auto insurance rates to increase for everyone to keep up with mounting claims costs.