The idea of tearing down the creaky Seattle waterfront viaduct and replacing it with a surface road is gaining momentum, according to this prominent Sunday newspaper story. Local politicians are calling for the surface-road option to be considered along with a tunnel and a replacement overhead structure. It's about time. The state and advocates of a pricey replacement tunnel say the no-rebuild option would lead to traffic chaos. But state data suggest that 50,000 cars a day would need to find a new route if the viaduct disappeared. The billions of dollars saved from a tunnel could go a long way toward meeting that need.