The first time you drive a car with lane-keeping assist, it might seem as if we’re on the verge of self-driving cars.The steering wheel turns itself and keeps you in between the lines.

Even though most systems require you to keep your hands on the wheel, it’s tempting to sit back and let it take over.But it only works if your car can “see” the lines. If the lines are faded, or you hit a little water on the road, the car could suddenly stop steering itself and leave you unexpectedly on your own.

“Autonomous vehicles and modern safety systems are able to read current road guidance indicators in fair weather,” Jonathan Cliffen, an application development engineer for 3M Canada, said in an e-mail. “Nighttime driving and driving in the rain limit the ability for these advanced systems to perceive their environment.”Lane-keeping assist systems use a camera to gauge the contrast between lines and the pavement.