It is used to wait for the traffic light while driving.
Perhaps there is a timer to display the rest of the waiting time. And then, we often glance at the timer for that check the time.

Focus on rest, get the ten of seconds free.
Raise your wrist after the meet traffic light. Set the hundred, ten and digit numbers refer to the rest of the traffic light timer. By use the digital crowd or numeric keyboard.
Perhaps, pick the appropriate time from the historical records.
The app notifies your wrist when three seconds remaining.
Change the rest time by plus or minus 3s after timer start.
Get ready, and continue driving.