Ads on elevator doors have been around some time, and their appeal is obvious: being front and center while people are waiting for the car to come down.

Volkswagen has taken the venue an important step forward with an ad that takes advantage of the motion of the doors opening and closing.

The ads, placed on some 100 elevator doors in Milan, Italy, have a car on either door, and as the doors close, it appears that the car on the right door will rear-end the car on the left door. Then the doors close fully, and the right car stops short of hitting the left door car.

The copy, appearing at the top of the ad, reads: “Keep a close distance.” Then at the bottom: “Volkswagen for safety.”

Just which elevator doors is also part of the message. The elevators are in eight hospitals in and around Milan.

“The idea of communicating inside hospitals gives the message the chance to reach the driver exactly when he’s particularly concerned about the problem of safety and health,” says Vicky Gitto, group executive creative director at DDB Milan, the agency that placed the ads.

Gitto says running the ads in hospitals enables Volkswagen to raise consciousness in the place where the notion of safe driving is most deeply felt.