Bruce Kirk of La Plata, Maryland, writes:Marilyn: I'm an instructor for AARP's Driver Safety Program, and I have more information about the four-way stop question.
(January 11, 2009) In the situation you addressed, the right of way must be yielded by the mail truck to the emergency vehicle to its right. You are correct that the states make the traffic laws, but all 50 states and the District of Columbia have the same laws concerning right of way. In the case of a four-way stop where neither of the roads is occupied or favored by signs or traffic lights, etc., two separate laws apply: a) traffic must yield to any emergency vehicle that is flashing lights and/or sounding a siren; and b) if vehicles are approaching or are stopped at the same time at an intersection, the vehicle on the left must yield to the vehicle on its right. The first supercedes the second, so the mail truck must yield