A professor of public policy at New York University says that driving under the influence of marijuana should be a traffic violation rather than a crime. According to the professor, drivers who smoke pot before they get behind the wheel are much less likely to crash than those who are using hands-free cellphones. While marijuana use doubles a driver's accident risk, hands-free cell phone use quadruples it.
The relatively minimal accident risk created by marijuana use is just one of the controversies related to marijuana impairment laws. A study by AAA found that the tests for THC impairment that are used by law enforcement have no scientific basis. Testing a driver's blood for THC can determine that the driver has consumed marijuana at some point, but the test cannot determine how impaired the driver at the time of the stop.
Some states set a legal limit for the THC blood level while others have a zero tolerance policy. Because different people can have very different reactions to the same levels of THC, some observers believe that the legal THC thresholds for drivers are meaningless. People who consume marijuana regularly may always have some THC in their blood even if they are not impaired.
DUI charges related to marijuana can have a similar adverse effect on a defendant's future as those involving alcohol if a conviction is obtained. Criminal defense attorneys can attempt to combat them in a variety of ways. As is the case with a drunk driving charge, they could choose to challenge the initial traffic stop as being made without probable cause, for example.