Hmmm this is a first,I worked with a gal who was a city driver for UPS Freight,and UPS never seem to mind her gender.
http://www.allgov.com/Controversies/ViewNews/Truck_Driver_Lawsuit_a_Winner_for_Women_100502
http://www.allgov.com/Controversies/ViewNews/Truck_Driver_Lawsuit_a_Winner_for_Women_100502