Save water; it’s easier than you think

So it said on a small sticker on the mirror in front of the Sloan automatic faucet in one of the Los Angeles International Airport restrooms. Why then, didn’t the automatic faucet use motion detection only to let water run instead of using a timer? When I wash my hands I follow four steps: 1) wet my hands, very shortly; 2) put some soap and rub my hands; 3) rinse my hands with water, a bit longer than the first time; 4) dry my hands. During the first step the faucet let water run for a period of time much longer than necessary, thus wasting water. If they had used only motion detection the system would have stopped water flow sooner when I was soaping and rubbing my hands and water would’ve have been saved; it would’ve been easier than what the Sloan engineers thought.