November 29, 2018
New research has found that traffic crashes have jumped in states that have approved recreational pot usage – namely Colorado, Nevada, Oregon and Washington. Now a number of school districts and bus drivers have even more to worry about on their daily routes, in addition to drunk drivers.
According to new data that was released several weeks ago, those states that have legalized marijuana for recreational use, compared with neighboring states that have not legalized pot, reported an increase in motor vehicle crashes, announced the Insurance Institute for Highway Safety (IIHS) and Highway Loss Data Institute (HLDI).
Marijuana is still an illegal controlled substance under federal law, and the size of the negative effect has varied by state, the report notes.
“The new IIHS-HLDI research on marijuana and crashes indicates that legalizing marijuana for all uses is having a negative impact on the safety of our roads,” said IIHS-HLDI President David Harkey.
States that are “exploring legalizing marijuana should consider this effect on highway safety,” he commented.
The study findings come as campaigns to decriminalize marijuana are picking up steam with many voters and legislators across the U.S. Meanwhile, Canada began allowing recreational use of marijuana last month.
The two new studies were presented at the Combating Alcohol- and Drug-Impaired Driving Summit in Ruckersville, Virginia on Oct. 18. The event was hosted by IIHS and HLDI, at the Vehicle Research Center. Highway safety and law enforcement experts discussed the prevalence and risk of alcohol- and drug-impaired driving, plus strategies to reduce that dangerous driving.
A review of those states showed that Colorado and Washington were the first states to legalize recreational marijuana for adults who are 21 and older, with voter approval in November 2012. Retail sales began in January 2014 in Colorado, then in July of that year in Washington. Oregon voters approved legalized recreational pot use in November 2014, with sales beginning the following October. Next, Nevada voters approved recreational marijuana in November 2016, and retail sales began in July 2017.
Frequency of Claims Jumped 6 Percent After Retail Sales Began
HLDI analysts estimate that the frequency of collision claims per insured vehicle year increased a combined 6 percent after retail sales of recreational pot were launched in Colorado, Nevada, Oregon and Washington, compared with the control states of Idaho, Montana, Utah and Wyoming. The combined-state analysis was based on collision loss data from January 2012 through October 2017, they said.
The analysts controlled for differences in key indicators:
Insured vehicle fleet
Mix of urban versus rural exposure
Rated driver population
Not surprisingly, collision claims are the most frequent type of claims that insurance companies receive. As readers may recall, insurers note, vehicle collision coverage insures against physical damage to a driver’s vehicle that is involved in a crash with an object or other vehicle, and usually when the driver is at fault.
Claim frequencies are reported as the quantity of claims per 100 insured vehicle years. So, an insured vehicle year is one vehicle insured for one year, or two vehicles that are insured for six months each.
A separate IIHS study that was discussed, examined police reports of crashes that occurred from 2012 to 2016, or before and after retail pot sales were launched in Colorado, Oregon and Washington. IIHS estimated that those three states combined experienced a 5.2 percent increase in the rate of crashes per million vehicle registrations, compared to neighboring states that did not legalize pot sales.
IIHS researchers also compared the change in crash rates in Colorado, Oregon and Washington, with the change in crash rates in the neighboring states that did not adopt recreational pot laws. Researchers compared Colorado with Nebraska, Wyoming and Utah, and then Oregon and Washington with Idaho and Montana. The study controlled for differences in demographics, unemployment and weather in each state, they commented.
Results Varied By State
The analysts explained that the size of the effect varied by state. Although the study controlled for several differences among the states, the models were not able to capture each difference. For example, “marijuana laws in Colorado, Oregon and Washington differ in terms of daily purchase limits, sales taxes and available options for home growers. These differences can influence how often consumers buy marijuana, where they buy it and where they consume it.”
However, the 5.2 percent rise in police-reported crash rates after recreation pot use was approved, was consistent with the 6 percent increase in insurance claim rates that were estimated by HLDI.
In addition to the study states, Alaska, California, Maine, Massachusetts, Vermont and Washington, D.C. also allow recreational pot use for adults 21 and older, plus medical use of marijuana. “Another 22 states allow medical marijuana, while 15 more states permit the use of specific cannabis products for designated medical conditions.”
Legalizing pot use is pending in New Hampshire, New Jersey, New York and Pennsylvania, analysts reported. Michigan legalized recreational marijuana earlier this month, though a similar vote failed in North Dakota. However, voters in Oklahoma approved medical marijuana in June, and Missouri and Utah followed suit three weeks ago.
Driving High is Illegal, But Measuring Impairment is Difficult
Driving under the influence of marijuana is illegal in all 50 states and D.C., but determining impairment is challenging. “Unlike alcohol, the amount of marijuana present in a person’s body doesn’t consistently relate to impairment,” the study authors stressed. “THC (tetrahydrocannabinol) is the primary psychoactive component of cannabis. A positive test for THC and its active metabolite doesn’t mean the driver was impaired at the time of the crash. Habitual users of marijuana may have positive blood tests for THC days or weeks after using the drug.”
The study authors explained that the role of pot in crashes isn’t as clear as the connection between alcohol and crashes. “Many states do not include consistent information on driver drug use in crash reports, and policies and procedures for drug testing are inconsistent,” they noted.
In addition, “More drivers in crashes are tested for alcohol than for drugs. When drivers are tested, other drugs are often found in combination with alcohol, which makes it difficult to isolate their separate effects,” analysts wrote.
14 Percent Used Pot
Also significant was the revelation in this latest study that 14 percent of 2,056 drivers (over age 21) tested positive for canabis use in the Washington State Roadside Survey. The survey was conducted just before and after retail sales of recreational pot began there in July 2014.
IIHS-HLDI’s Harkey also concluded that legalizing pot is negatively impacting motor vehicle safety.
“Despite the difficulty of isolating the specific effects of marijuana impairment on crash risk, the evidence is growing that legalizing its use increases crashes,” he said.