This is the bridge over the Cedar River between the Renton Airport and the Boeing factory. They apparently use it to move the planes from the factory to the paint shop and to the airstrip over the river. Many cyclists doing the Lake Washington loop ride would use this bridge while using Perimeter Rd, the Cedar River Trail and N. 6th St. In lieu of the Boeing bridge, one needs to do N. 6th St, the trail to the Logan St./Cedar River bridge, and then the south tip of the airstrip. I'm told the recent fatal collision on the trail has led to a strict 10mph speed limit, too.