My father served with the 51 Highland Division which landed in the days after D Day. The division was sent to the Eastern side of the beachead to reinforce the Airborne troops (paras and airlanded) and in their tradition plastered the route including the canal and river Bridges with the Divisional HD sign, hence their nickname of Highway Decorators.
After protests from the airborne troops they were made to remove the HD symbol from the bridges they have been known as Pegasus (canal) and Horsa (river) bridges ever since.