PORTLAND, Maine (NEWS CENTER) -- Recent changes to state and local marijuana policies have some members of law enforcement concerned that they could see an increase in the number of drug-impaired drivers.

"People are already doing it," stated Cumberland County Sheriff Kevin Joyce.  "When it was illegal people were already doing it as well."

Before he became sheriff, Joyce was a highly trained drug recognition expert, and was often called upon to assist other officers in helping them determine not only if a someone was impaired, but what drug they had taken.

When a driver is suspected of being drunk, police officers have tools to help them make that determination, with drugs it often requires an intensive investigation.