OLYMPIA (AP) — Delays on the tunnel replacement for the Alaskan Way Viaduct through Seattle are now expected to cost the state about $149 million in overruns, a third less than feared in July.

Joe Hedges, program administrator for the Washington State Department of Transportation, said the main reason for the revised figure is that tunnel-boring machine Bertha has made steady progress since spring, and completed 72 percent of the route from Sodo to South Lake Union.

The Seattle Times reports the agency issued new figures Thursday to state lawmakers after telling them in July that the worst-case situation would add $223 million in overruns on the $2.1 billion tunnel, which is the biggest piece of a $3.1 billion replacement for the old Alaskan Way Viaduct.

The project is now three years behind schedule, with the expected opening in spring 2019.