2003 Ford Focus used as the smoking car

In this photograph taken Thursday, April 16, 2015, smoke created by water vapor billows out of the windows of a car during a demonstration by the Colorado Department of Transportation in southeast Denver. Colorado authorities took the car to fight stoned driving right to the target demographic -- males 21 to 34 years of age -- at public rallies and concerts in observation of the 4/20 marijuana holiday. (AP Photo/David Zalubowski)

(David Zalubowski)

Just because a motorist may look stoned doesn't mean they're driving impaired, a Massachusetts judge found in a evidentiary hearing for the state Supreme Judicial Court.

Despite acknowledging a correlation between marijuana consumption and impaired driving, Central District Court Judge Andrew M. D'Angelo said a universal and legally fair way to determine at what point one qualifies as impaired on marijuana remains elusive.



A police officer cannot accurately determine the impact of marijuana consumption on a particular person's ability to drive, D'Angelo found.



D'Angelo based his finding on studies which found a vast majority of people under the influence of THC, the intoxicating ingredient in marijuana, still pass field sobriety tests, especially when accustomed to the substance.



Even 50 percent of non-frequent smokers pass field sobriety tests, another study found.



Attleboro Attorney Michael DelSignore, in a weekend blog post agreeing with the finding, said he expects the Supreme Judicial Court will as well.

"I expect the SJC will affirm Judge DeAngelo's decision and hope that this case will be followed nationally by other courts addressing this issue," DelSignore wrote.



At the heart of Massachusetts' ballot Question 4 -- the legalization of marijuana for recreational and commercial use, approved by a more than 50 percent majority of voters Tuesday -- was the question of road safety.



Opponents used the potential for more impaired drivers on Bay State roads and highways as a key argument in their favor, while supporters pushed back, saying the consumption of the legal drug alcohol compromises one's ability to drive to a much greater degree.



In the run up to the election, various municipal police chiefs said they intended to patrol for motorists intoxicated on marijuana the same way they do for drunk drivers.



Judge D'Angelo's finding casts doubt on the viability of such an approach.



Several potential problems the judge identified have already been recognized other places where commercial and recreational marijuana has already been legalized.



Red eyes and drowsiness may indicate a stoned driver, D'Angelo found, but he also said there's "no evidence that these characteristics equated with impaired driving," according to DelSignore.



That creates problems if a police officer is attempting to arrest or charge a detained motorist after identifying these traits.



"An (operating under the influence of marijuana) charge is a very winnable case, because typically the commonwealth will have no evidence as to how much you smoked, when you smoked and will lack an expert to say what impact any marijuana intake would have on your ability to drive," DelSignore adds in a post on his website.



The Department of Transportation in Colorado, where recreational marijuana has been legal since 2012, says "any amount of marijuana consumption puts you at risk of driving impaired," on its website.



"No matter the level of THC, law enforcement officers base arrests on observed impairment," the website adds.



The official legal limit of THC impairment while driving in Colorado is five nanograms of active tetrahydrocannabinol in a person's blood determined by blood test, according to the website.



However, some have tested the limit and found smokers can still turn up far over the limit after a night's sleep and 15-plus hours after consumption -- and after being deemed sober by a physician.



The SJC will hear arguments on the case beginning in January, according to DelSignore. D'Angelo's finding could lead to a different approach being taken by Massachusetts law enforcement, but what that might be remains to be seen.





