While outgoing Attorney General J.B. Van Hollen says the biggest law enforcement challenge his successor will face is curbing heroin and prescription drug addiction in the state, he also says enforcing marijuana laws is likely to become a growing problem.

Van Hollen said legalization of pot in Oregon and Colorado has made the drug more available, and that he’s especially worried about people driving while under the influence.

“Everybody is in uproar about the dangers and evils of drunk driving,” said Van Hollen. “I don't think people have stopped to realize the evils of ‘drugged driving’ once marijuana becomes more mainstream.”

Van Hollen said establishing what level of THC in a driver’s blood should be considered dangerous and lead to prosecution may become an important legislative challenge.