The Bicycle Beltway is a nickname given to a combination of trails that would make a circle around NW DC. It includes the trail along the National Mall, the Potomac section of the Rock Creek Park Trail, the Capital Crescent Trail and the Metropolitan Branch Trail. The last two trails on that list are not yet complete, but doing so would increase bike commuting and transportation, not just into and out of DC, but suburb to suburb as well. Luckily, this entire project is being planned, which is all the more impressive when you realize that it is actually four separate projects.
First there is the effort to complete the Capital Crescent Trail. Currently it is paved from Georgetown to Bethesda, but from there to Silver Spring it is either unpaved or on road. That could all be changed with construction of the Purple Line. The Purple Line, if built, will use the same ROW as the interim CCT from Bethesda to the end of the old rail spur and will then continue into Silver Spring and to points beyond. In addition to paving the trail and allowing for the trail to go off-road into the Silver Spring Transit Center, it would also remove the at-grade crossings at Connecticut Avenue and Jones Mill Road. It would connect to new neighborhoods like Woodside. And, or course, it would connect to all of the Purple Line stations along the route. The current interim trail is significantly less popular than the permanent trail - getting half as much traffic on the west end and only 1/10th as much at the east end. It's not unreasonable to believe that traffic on the new trail would match or exceed traffic on the existing western section. The trail is part of the Purple Line functional master plan, as it likely must be, due to the railbanking statute under which it was acquired. While this is all good news for those who support the trail, none of this is funded. And the Purple Line is at least four years away from breaking ground, so the project is going to need sustained support to see fruition.
The next project of importance is Montgomery County's section of the Met Branch Trail. This trail will connect to the CCT at the Silver Spring Transit Center and with the DC section at the boundary. Part of this trail, a section alongside Fenton Street and Takoma Avenue to the DC boundary, is complete and has been for several years. A short section of the trail is also being built with the Silver Spring Transit Center. But the remaining section between these two are years away. Phase I, which would extend the trail from the Silver Spring Transit Center south through the Ripley District and across Georgia Avenue on a new trail bridge has been budgeted and is scheduled to be built in 2016. Phase II, which will complete the Montgomery County section, will be designed at the same time as Phase I, but will have to wait longer to resolve CSX and SHA issues. It is expected to be completed in 2019.
The third project is the remainder of the DC section of the MBT. Sections of this trail have already been built, creating a continuous trail from Union Station to Franklin Street. The EA for the whole trail has been completed and design should already have begun on the section from Michigan Avenue to 1st St NE. But it's unclear when that section, or the not-yet-designed section north of that, would be built. It will probably be several years before the entire DC section is finished.
The final piece is the Prince George's County Connector, though not part of the beltway, it has the potential to be a strong complement to it by connecting the MBT to the Anacostia Tributary Trail system. A very short section of this trail has been built in the Avondale neighborhood. DC included their section of this trail in their EA, so it appears to be making progress on that at well. It is unknown when DC would build its section or when Prince George's County will build its remaining section from Avondale to the Northwest Branch Trail. The PG County trail is on indefinite hold.
Once all of these projects are completed, and that could be over a decade away, it will create new connections between DC and the inner Maryland suburbs. The number of trips coming into and out of DC on the Met Branch Trail should go way up, as will trips east-west between Hyattsville and Bethesda. It is arguably the most important set of facilities being built in the DC area and it's important that they continue to move forward.