The Hood River-White Salmon Interstate Bridge will be closed to all vehicle traffic tonight and tomorrow night from 9:30 p.m. to 5 a.m.  The Port of Hood River is advising motorists they expect traffic congestion to take place at around 9 p.m. both nights, so plan trips accordingly.  Motorists must use alternate routes to cross the Columbia River during the closures, with the Bridge of the Gods in Cascade Locks and the Highway 197 Bridge in The Dalles the closest crossings.  The closures are required for the replacement of the bridge lift span motors.  Emergency response vehicles will coordinate Hood River-White Salmon crossings during active emergencies via 911 dispatch.