New Jersey lawmakers failed to agree on a plan to legalize marijuana in late March, which temporarily staved off a new wave of high-risk driver behavior from those who indulge.

Democratic Gov. Phil Murphy, who couldn't gather enough support in the state's Senate for the initiative, is expected to continue pushing for legislative approval of recreational use rather than the public ballots used to pass recreational and medical use of the drug in 10 other states. That would likely increase the risks associated with fleet drivers who use the drug, as well as the number of drugged drivers on the state's roadways.

"We are relieved that New Jersey did not pass that law, even though we know it is only a matter of time before they do pass a law legalizing marijuana," said Michael Freidel, the fleet systems and maintenance manager of Asplundh Tree Expert and chair of NAFA's Philadelphia chapter.

After the state's Senate called off a vote on the proposal, Murphy vowed to fight on.

"Eventually barriers do fall to those who are committed to breaking them down," he told reporters, including the New York Times.

A wave of marijuana legalization measures have arrived on the ballots of U.S. states in the past year, and have mostly been approved by voters. Recreational marijuana is now legal in Alaska, California, Colorado, Maine, Massachusetts, Michigan, Nevada, Oregon, Vermont, and Washington. Medical marijuana is now legal in 33 states.

A report released earlier this month from the American Transportation Research Institute highlighted the risk of increased impaired driving in states that have legalized marijuana. Law enforcement officers often have trouble detecting the drug, because there is currently no breathalyzer-type test they can use.

The study recommended increased data collection on the frequency and impacts of marijuana-impaired driving; public education and information on the risks of impaired driving; better equipping law enforcement and the court system to intercept and ultimately prosecute impaired drivers; and targeting tax revenue generated from marijuana sales to fund these activities.

Fleet managers must be sure to develop and disseminate written policies that bar drivers from using marijuana or other substances while operating a company vehicle, said Freidel.

"As far as we are concerned, we will treat marijuana as we do with alcohol, prescribed medications, and illegal drugs," Freidel said. "It will not be tolerated. Our policies have been revised to address our concerns, and any driver found driving impaired due to marijuana will be disciplined. The bottom line is that if any of our drivers are impaired, regardless of the substance, they are putting the general public at risk."

Fleet managers may also need to deal with other forms of cannabis, such as cannabidiol (CBD) oil, which is becoming a more popular natural alternative to pain medicine. Its use in topical form can trigger a positive DOT drug screen.