ANNAPOLIS, Md. — How can you tell when someone has had too much to drive when what they've had is hard to measure?
That's the case with THC – the part of marijuana that makes you high.
A bill making its way through the Maryland legislature could give police officers access to a device that could better tell who is too high to drive.
Recently, Montgomery County Police invited medical marijuana users to get high in front of some of its officers to help the officers learn how to spot drivers impaired by pot – a skill Montgomery County believes its officers will need even more with recreational marijuana coming to Maryland this summer.
"I'm very worried because I know unequivocally this is going to increase the amount of impaired drivers we have out on the streets," said Capt. Brian Dillman with Montgomery County Police Department at the January event.
Dillman said if other states with legal weed are any guide, the road ahead will have more impaired drivers with no standardized test for police to prove it.
Because THC affects the body differently than alcohol, there is no breathalyzer-equivalent for marijuana.
"We need new technologies to see if we can find a way to measure this level of intoxication," said Maryland State Sen. Jeff Waldstreicher, a Democrat from Montgomery County.
Waldstreicher says because he supports legal weed, he's trying to give police a tool to easily determine who's too high to drive based on cognitive impairment.
"Allowing adult use cannabis is only credible if we disallow cannabis intoxication while driving," said Waldstreicher. "Police are definitely worried about it. I'm worried about it as a lawmaker, but I'm especially worried about it as a father."
"We've seen in states like Colorado that were early to legalization an increase in driving while intoxicated and an increase in accidents and deaths," Waldstreicher said. "We want to see if we can head that off in Maryland."
Waldstreicher introduced a bill that would allow tech companies to partner with police departments on a trial basis to test new ways of determining a driver's impairment.
And a device made by the company Cognivue could be the first. It's an FDA approved mobile cognitive test.
The iPad-like device uses a wheeled joystick to test problem solving, perception, and other reactions to detect brain issues like Alzheimer's.
The company, and Waldstreicher, believe it could also help police officers test for the effects of marijuana and determine if a person should be driving.
Cognivue told WUSA9 it has tested the device in the lab, but the company needs to see the device on the streets to make sure it works in a roadside situation.
The test would take a driver about two minutes to complete. And because the driver taking the test is the only person interacting with it, Cognivue believes the test will be less susceptible to any biases an officer may have.
During this trial phase results could not be used against the driver in court.
But will drivers volunteer after being pulled over?
"So that's a legitimate question," said Waldstreicher. "I think we have to put it out there and see the results."
"It benefits everyone to have this technology perfected. And, so I think we're moving in the right direction," he said, adding that his fellow law makers have, so far, not objected to his legislation.