The city of Falls Church is rebuilding the Van Buren Bridge over Four Mile Run in Benjamin Banneker Park. A spur of the W&OD Trail connects to Van Buren just south of the bridge and a repair was needed here. The bridge had gotten so bad that the sidewalk had been closed and replaced by a flexpost protected walkway.
During construction, expected to last until March 2018, pedestrian and bike traffic will be redirected onto the trail
The Van Buren Bridge project will replace the existing Van Buren Bridge to accommodate pedestrians along this corridor to the East Falls Church Metro. The current bridge has no pedestrian access and has been identified as “structurally deficient” during its annual inspection. The new bridge will accommodate two lanes of vehicular traffic and have a 12' pedestrian walkway on the downstream side.
It also appears that it will include bicycle markings that aren't quite sharrows. I'm not sure what these are. I guess they're what you go with when sharrows seem too aggressive. "We want drivers to share the road, but in a modest way. We're not a bunch of hippies."
The crosswalk (which I'll note is not zebra striped) and sidewalk represent a connection between the end of the W&OD Trail spur and the start of a footpath along the south side of Four Mile Run.