In 2009, Murray was the prime sponsor of a $2.4 billion Washington Senate financing bill authorizing the construction of a deep-bore tunnel underneath Seattle to replace the Alaskan Way Viaduct. Murray advocated for the project, which attracted well-documented concerns. Bertha, the machine drilling the deep-bore tunnel, broke down in December 2013, leading to costly delays and significant challenges such as destabilizing soil conditions under Seattle's historic Pioneer Square and the Viaduct itself. As of mid-2018, cost overruns on the tunnel project exceed $600 million.