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The View Beyond the Viaduct Half a century after it opened for traffic, the Alaskan Way Viaduct has once again drawn the attention of city and state engineers, who want to replace it before a major earthquake forces their hand. If the highway is ultimately put underground, that would open up the waterfront to views and new developments, as envisioned here: parks, a new trolley route, bike paths and greenbelts that could connect landmarks from Safeco Field and the Pike Place Market to Seattle Center and even South Lake Union. There are no cost estimates, but think billions of dollars. Lacking tax dollars, tolls are likely. And advocates argue that burying the highway creates new possibilities for helping pay the tab by leasing surface and air rights to private businesses in what has become a high-rent area. Some possibilities Options include a new elevated highway, built to withstand an earthquake; a "cut-and-cover" highway similar to the I-90 freeway across parts of Mercer Island; a deep tunnel; or, most likely, some combination. Most city leaders prefer to put the downtown portion underground, using the new highway walls to rebuild the downtown seawall — also considered vulnerable to earthquakes. Cut-and-cover tunnel/aerial structure A new viaduct for cars going southbound, a shallow tunnel for northbound traffic. Double-deck cut-and-cover tunnel A tunnel that accommodates all former viaduct traffic. Deep tunnel A deep "bored" tunnel — most likely at the north end, linking the waterfront with Aurora Avenue. MICHELE LEE MCMULLEN / THE SEATTLE TIMES