At three in the morning a commercial lot along Route 50 is just a white rectangle under pole lights, and somebody has to make it a parking lot again by six. RDM Construction Companies works that window all winter — plowing lots and driveways, stacking snow where it will not block sight lines, shoveling entrances and salting the walks. Saratoga Springs storms often taper straight into the morning rush, which means running the last pass while the first cars arrive. Ice after a thaw asks for as much attention as the snowfall did. The result is unremarkable in the best way: open pavement, dry doorways, a normal morning.