before the construction of the Interstate Highways or State Route 520; the original Lake Washington Floating Bridge (opened 1940) provided the only road out of town to the east; construction of the Alaskan Way Viaduct, the first limited-access highway through the city center, was still underway. Even with the lesser population of that time and fewer major highways, difficulty parking downtown had already become "practically an institution". The total number of vehicles parking downtown in a day would already have filled a parking lot the size of downtown had they all been there at once; naturally, many of these were there only briefly for shopping. Parking meters had been introduced in the early 1940s, and multi-level parking garages provided some relief (and would later provide more), but the impact of the automobile on the city was very apparent. The city was considering various proposals, such as the establishment of large parking lots on the periphery of downtown with shuttle buses into the center. The city was seeking (and failing to get) state permission to use the right of eminent domain to acquire property for multi-level parking lots. Later, in the mid-1960s, the historic Seattle Hotel building was torn down for just this purpose; the reaction against that sparked the preservationist movement for the revival of Pioneer Square and made it clear that the city would not solve its problem by demolishing a ring around downtown. Over 15,000 Seattleites are members of the car sharing program Zipcar (formerly Flexcar). While not all members are frequent users, the use of these shared cars has been substantial enough to justify the purchase of over 150 cars and other light vehicles for the program, with an additional vehicle purchased approximately every ten days. Two other car-sharing services, Car2Go and ReachNow, operate within Seattle. SR 99 Tunnel The SR 99 Tunnel is a bored double-decker highway tunnel carrying a section of State Route 99 (SR 99) under Downtown Seattle from SoDo in the south to South Lake Union in the north. Since the 2001 Nisqually earthquake, the replacement of the Alaskan Way Viaduct has been the source of much political controversy demonstrating the Seattle process. Options for replacing the viaduct, which carried 110,000 vehicles per day, included either replacing it with a cut-and-cover tunnel, replacing it with another elevated highway, or eliminating it while modifying other surface streets and public transportation. The current plan emerged