Jeff beat me to this, but I'd already written it, so...
The National Park Service recently announced that they would begin reconstruction of the George Washington Memorial Parkway's Humpback Bridge.
Construction improvements, slated to begin in January and end by spring 2010, include widening the bridge, adding barriers to better separate pedestrians from traffic and building tunnels under the bridge so that people can get to both sides without walking through traffic.
Although many of the improvements are aimed at helping motorists, a number of additions will aide pedestrians, Snyder said. She cites the example of a sidewalk that currently runs alongside the roadway, noting that a person riding a bike on that path risks falling into traffic.
"The need is great to eliminate the danger there," said Bill Line, a spokesman for the National Park Service. A waist-high, stone-faced barrier will be erected to better separate the roadway from pedestrians, bikers and joggers.
The pedestrian crosswalk will be replaced with two tunnels to keep visitors from having to walk through traffic to get from the Potomac shoreline side of the parkway to the Columbia Island Marina side, Line said.
"It will eliminate the need for any human being on foot or bicycle or whatever to risk getting hit by a car and risk a fatality," Line said. "Our concern is safety first and foremost, with those two tunnels underneath and obviously placing those barriers."
This project made up part of one of my 2005 Christmas Wish List items - a few of which are finally starting to happen.
Though they don't mention it, and the drawing of the cross-section (above) doesn't show it, it appears the sidepath will be widened - if the drawing is to scale, which it may not be. I love the odd choice of cars.
In addition to widening the path, the bridge will do much more for cyclists. It will trade out a dangerous at grade crossing for two grade separated crossings - one on the D.C. side and one on the Virginia side. It will reroute the trail, so that riders going north won't have to take a sharp right turn and then go around the Memorial. Instead they'll continue in a straighter, flatter path between the road and the memorial. New trails will be built along the Boundary Channel, both of which will provide better access to the Pentagon.
As Jeff stated, it's unclear how much the trail will be impacted during construction.