Research shows that increasing rates of marijuana use have resulted in an increased rate of car crash fatalities. It is a problem that many proponents for legal adult use of recreational marijuana wish to pretend does not exist.

In fact, Vermont Gov. Phil Scott vetoed his state's marijuana legalization bill today with concerns about public safety on his mind. Scott is sending the bill back to the state legislature, asking for harsher penalties for those who drive under the influence.

"If they're willing to address concerns in a new bill, there is a path forward on this issue," Scott said in a press conference. "But we must get this right."

In an effort to better prepare those New England states that have recently passed legislation allowing for recreational adult use of marijuana — Maine and Massachusetts the American Automobile Association (AAA) of Northern New England and the Maine Bureau of Highway Safety recently held an Impaired Driving Summit, bringing together experts from across the nation.

Marilyn A. Huestis, Ph.D., an adjunct professor at the University of Maryland School of Medicine and considered to be the world's leading expert on the biologic assessment of cannabinoids within human systems, gave an update on driving related research.

Huestis provided education regarding biologic testing to an audience consisting of primarily law enforcement specialists and administrative personnel associated with municipalities and organizations that will be dealing with the increased numbers of marijuana-impaired drivers. This information is critical for law enforcement and was updated from her presentation at the first summit sponsored by the federal National Institutes of Health on cannabinoids, held about this time last year.

Huestis continues to advocate for more research to enable better tools to detect marijuana-impaired drivers. Lt. John Flannigan, the Traffic Operations Commander in Vermont and the state coordinator for the Vermont Drug Evaluation and Classification Program, contributed to the discussion of biologic testing from a law enforcement perspective in his overview lecture on "Oral Fluid Testing." Some of the practical aspects of biologic specimen collection were covered.

Chris Halsor of Understanding Legal Marijuana, LLC, a former Colorado traffic safety resource prosecuting attorney with expertise in impaired driving, provided an overview of the Colorado experience. Halsor was recently hired by the state of Nevada to act as the state's traffic resource prosecutor for rural communities in order to provide services and training in response to Nevada's recent approval of legal recreational marijuana.

Starting in 2014, Halsor in collaboration with the Colorado Attorney General's Office developed a four-hour course targeting law enforcement officers: "Marijuana 101: An Introduction to Legal Marijuana for Law Enforcement." He has also developed basic drug recognition expert (DRE) courses specific to teaching law enforcement officers how to more effectively investigate marijuana impaired driving.

Part of these courses includes a "Green Lab" where volunteers are dosed with marijuana so as to demonstrate the impairments. This live laboratory experience is the only such experience available anywhere in the United States.

Lt. Col. Kevin Eldridge of the Colorado State Police provided an overview of the Colorado perspective titled, "Driving High: Colorado Enforcement Efforts." He acknowledged that the marijuana-impaired driving problem is complex and as of yet there are no good comprehensive solutions. Eldridge brings the perspective of a trained defensive driving course instructor and additional expertise in accident scene reconstruction.

The federal perspective on marijuana was discussed in the presentations by Michael W. Wardrop from the U.S. Drug Enforcement Administration (DEA) and Eric C. Adair representing the Federal Motor Carrier Safety Administration. The closeout of the summit featured presentations specific to the judicial perspective and the courtroom experience related to marijuana-impaired driving.

The Supreme Court case that resulted in the need for a warrant to obtain blood specimens was reviewed by Scot Mattox of the Maine Bureau of Highway Safety and Patt Mador an Assistant District Attorney of Sagadahoc County Maine. A view from the bench was provided by Honorable Brian Burgess the Judicial Outreach Liaison for the National Highway Transportation Safety Administration.

Data from states having legalized recreational marijuana are indicating that there is a significant risk of a fatal crash with marijuana use. Meta-analysis studies support this.

The AAA states that the best resource to identify impaired driving are drug recognition experts, who are highly specialized law enforcement officers. But short of that, providing education about marijuana-impaired driving to transportation professionals and law enforcement will help prevent some of the fatal crashes that are occurring.