Seattle's Alaskan Way Viaduct is likely either to be rebuilt or else replaced by a six lane tunnel, Washington State officials have said. These are emerging as the most popular and likely of five options, ahead of a new larger bridge, a bypass tunnel or a surface route. The deteriorating viaduct suffered earthquake damage in 2001. It has been assessed as having a 1 in 20 chance of being hit within 10 years by an earthquake large enough to force its closure.