A research team backed by two British insurance companies came out with the study, which claims driving with a cold can be equivalent to downing more than four double shots of whiskey.
Sick drivers have diminished reaction time, have trouble negotiating curves and brake suddenly, according to the study.
The determination doesn't shock state troopers.
"It's taking away your attention," said WSP trooper Keith Leary. "You're more focused on your cold than you are on your driving."
That's what happened to Daniel Zeufeldt, who was stone sober but sick with a cold when he was recently pulled over.
"I was reaching over to grab a tissue and weaved a little bit," he said.
Leary said the study should be a wake-up call that sick motorists should pause before they start their cars.
"You should be evaluating yourself," he said. "Can I drive safely while I'm feeling as ill as I am?"
Leary also said drivers should be especially careful if they're taking cold medicine that causes drowsiness.
While there's no law against driving while sick, Zeufeldt's story is proof that it can get you into trouble.