The Wisconsin State Patrol saw a 20-percent increase in drug arrests from 2016 to 2017. The number rose from 2,862 in 2016 to 3,439 last year, according to the law enforcement agency.

A drug arrest involves possession of illegal narcotics or paraphernalia. Along with drug arrests, the State Patrol also says there was an increase in drugged driving — driving while under the influence of a controlled substance. There were 312 drugged driving arrests in 2016, and it increased to 386 in 2017.

State Patrol Lt. Chris Joshka said there isn’t one reason for this increase, but there are several contributing factors, like better trained officers and marijuana legalization in other states.

Decriminalization and legalization of marijuana in neighboring states and around the country means the transportation of more illegal substances, Joshka said. Illinois, Minnesota, Michigan, and Ohio have legalized medical marijuana.

Sign up for daily news! Stay informed with WPR's email newsletter.

"That marijuana is bound to be moved through the state, and our officers are starting to see more of that," Joshka said. "So I certainly think that there’s a rise in drug arrests based on the fact that marijuana has been legalized in some of these states and we’re seeing it being transported to and from through Wisconsin."

The State Patrol gave more than 100 officers last year what's called advanced highway criminal interdiction training.

"I think this has a huge effect on our ability to identify people who are transporting illegal contraband," Joshka said.

Nationwide there were more drugged driving fatalities than drunk driving in 2015.