If your nose looks like a radish and your eyes are more watery than chicken soup at a bad diner, the only equipment you should be operating is a thermometer.

The common cold, it turns out, is an automobile accident waiting to happen. The sneezing, tearing, fever and puffy eyes make your reactions behind the wheel as slow and unsteady as a party-goer who’s pounded back several drinks, reports a UK team.

One reason: A single sneeze lasts two to three seconds, and your eyes automatically close during it. If you’re driving 70 miles an hour and go “ah-ah-ah-choo,” you’re driving blind for 315 feet. You don’t need us You Docs to tell you that’s scary. It also explains something we didn’t understand in the past: why getting a flu shot decreases accident deaths.

North Americans get 1 billion colds each year. So you can bet that many sneezing, blowing, dripping drivers will be bobbing and weaving down highways. Don’t be one of them.

What if you have a ferocious cold and absolutely have to go someplace? Do not take the nearest cold medicine without checking the warning label. Many contain decongestants that can give you the shakes, or make you nod off or respond slower. Instead, pick up the phone and ask a friend or a taxi service for a lift.

Once you’re back on your feet, stave off your next battle of the sinuses with this trio of cold-fighters: Get eight hours of sleep nightly. Take 1,000 IU of virus-fighting vitamin D-3 daily. And wash your hands like a maniac.

The You Docs — Mehmet Oz, host of “The Dr. Oz Show” and Mike Roizen of Cleveland Clinic — are authors of “YOU: Losing Weight.” To submit questions, go to www.RealAge.com. A King Features syndicate.