This page is an excerpt from Kamala’s planning thesis regarding alternatives to rebuilding Seattle’s Alaskan Way Viaduct. Her paper discusses the viability of highway capacity reduction as a strategy for retro-fitting downtown Seattle for sustainable transportation and land use.
Seattle’s Alaskan Way Viaduct
Download the full research paper here.
Many of the arguments for replacing the Alaskan Way Viaduct (with another viaduct or tunnel) hinge around the purported imperative of rescuing the parallel stretch of I-5 from ‘gridlock’. The charts below use published demand projections to estimate when I-5 will be ‘gridlocked’ anyway, even if the new viaduct or tunnel is built. While this model is not meant to be predictive, it does demonstrate the fallacy behind trying to build your way out of congestion. In this case the multi-billion dollar investment in a tunnel or viaduct only delays I-5’s gridlock by ~10years.