At the Trafalgar Square end of Northumberland Avenue, there is a pedestrian crossing. These lights turn to red after traffic coming from The Mall and Cockspur Street proceeding straight to Northumberland Avenue or right into Whitehall have had their green phase. When the lights in the middle of Trafalgar Square turn red, these lights then turn red about four seconds later, as an additional safeguard for pedestrians crossing, so that slow-moving traffic over the first stop point - but still proceeding, do not continue to creep across the crossing. Unfortunately, there is at present no white line marked on the road at this point, so drivers assume that the red lights are a mirror of the previous set and not a new stopping point. Accordingly, they plough on through a green man. Could I ask why there is no white line marked on the roadway?