GRAND ISLAND, Neb. -- Nebraska ranks highest for the percentage of drunk drivers on the road - that's according to the Centers for Disease Control and Prevention.
But another risky behavior is a rising concern while driving.
NTV's Cheryl Hwang rode along with an officer while a man was arrested for a drug DUI.
According to the definition from the Grand Island Police Department, a drug DUI is categorized as when a person is driving under the influence of any substance - other than alcohol- put into the body that can impair the ability to drive.
"Be honest with me how much marijuana do you have in your vehicle?" Officer Andre O'Connor of Grand Island Police asked.
A college student out for ice cream got pulled over for speeding during the ride along.
"I don't. I don't have any," the student said.
"I'm going to give you one more chance to be honest with me. Why does your car smell like marijuana?" the officer asked.
The student was arrested for driving under the influence of marijuana.
"You're extremely nervous, and shaking," O'Connor pointed out during the arrest.
Police said this case is one of 81 other drug DUI cases so far this year in Grand Island.
Most people think of DUI as drunk driving, but drugs make up a large percentage.
According to police that percentage is rising, from 16 percent four years ago in 2014 to 39 percent now.
Officer O'Connor said Grand Island was the first to be a part of the Drug Recognition Expert Program (DRE) in Nebraska because the city has had a long drug problem.
He questioned the young man in custody and took him through the official drug recognition process.
"We have definitely had an increase in DUI drugs cannabis related categories and I think that is directly related to legalization of marijuana in Colorado in 2014- so the spike or the increase in cannabis related arrests is contributing to the legalization of marijuana," O'Connor said.
The officer said you can be driving under the influence of not only illicit drugs, but also common medication.
"DUI drugs can be over the counter or prescription drug use. And if your doctor prescribes you medication and it impairs your ability to operate a vehicle safety, you could potentially be arrested for DUI drugs," O'Connor said.
Officer O'Connor said he has arrested some people on ADD medication, anti-depressants and painkillers.
He also said the best way to avoid getting arrested is to check your prescription.
"If it gives you caution or label on there -- 'use caution while operating any motor vehicle or heavy machinery' -- you should probably not operate a vehicle," O'Connor said.
Officers said Grand Island has the highest number of drug DUI cases in the state of Nebraska - more than Omaha- but there are that many more DRE officers proactively combating these cases.