The $82.7 million construction contract for the transit tunnel renovation was awarded to Balfour Beatty in August 2004, 12 percent below Sound Transit's estimates. The majority of the cost was paid by Sound Transit and supplemented by $8.1 million from King County Metro. As part of the renovations, the tunnel's roadway was lowered by to allow for level boarding, required by the Americans with Disabilities Act; as a result, Metro added strobe lights to bus mirrors, which were lowered to head height, and added warning signs. New electrical, mechanical, and emergency systems were installed, along with a new communications system connecting to a joint-operations center. The project ended up costing $94 million in total, 3.4 percent over the budget set in 2004. During the closure, Metro found that average travel time through downtown increased only 11 percent during the afternoon peak period, and ridership on popular routes only dropped slightly.