There should be an additional field in the calendar forms where you could add the time needed to get to a meeting.
i.e. the meeting starts at 2 PM but you need to get out of the office at 1 PM in order to be at the customer site on time. It should also be reflected in the calendar view so that anyone checking the calendar is aware that someone is travelling or at the meeting itself. Additionally it should be linked to resource reservation.
Since this item has been mentioned at the LS 09 "Ask the developers" session I'm "re-posting" my idea.