New bridges to accommodate highway traffic crossing the canal also became necessary as deepening and widening progressed. Two mechanical lift bridges at St. Georges and Chesapeake City were toppled by ship collisions and replaced in the 1940s with high-level highway spans (the former, the St. Georges Bridge, has largely been bypassed by the new Senator William V. Roth Jr. Bridge, opened in 1995). Two other high-level vehicular traffic bridges, Summit Bridge in 1960 and Reedy Point Bridge in 1968, were constructed as part of the 1954 improvement authorization.