During daylight saving transitions we either lose or gain an hour, which changes the overall length of the day.
Over a daylight saving transition we look at the total status durations irrespective of the time on the clock.
Someone drives from 1am to 5am during a night when daylight saving time ends. At 2am the clocks are changed backward by one hour. The observed status duration is five hours.
Someone drives from 1am to 5am during a night when daylight saving time starts. At 2am the clocks are changed forward by one hour. The observed status duration is three hours.
It is important to understand that, regardless of the recorded length of a day when a daylight saving transition occurs, your HOS working hours and break obligations remain unchanged. You cannot legally work an additional hour, or claim an additional break hour, if your shift includes a change in time.