A new long-term “blueprint” to dramatically expand Northern Virginia’s bus rapid transit lines calls for significant investment along core Arlington routes.

A draft Bus Rapid Transit Action Plan , unveiled yesterday (Wednesday) is meant to guide agencies throughout the region as they consider future transit investments. A proposed map of possible BRT lines envisions two routes connecting Columbia Pike to Crystal City and D.C., and another route running east from Falls Church into Rosslyn, across the Potomac River and into Georgetown.

According to Northern Virginia Transportation Authority (NVTA) estimates, all three of these routes would be some of the most heavily trafficked in the entire region.

A full build-out of the proposed BRT network is estimated to cost about $4.2 billion — but the action plan won’t obligate agencies to invest any funding. Instead, NVTA spokesperson Abigail Hillerich said that it’s meant to provide a region-wide vision forming the basis for future investment.

“This was really establishing a solid blueprint,” Hillerich told ARLnow. “Somebody had to step up and do it, and really look at how we can connect more people.”

Overall, the proposal envisions a coordinated network of 28 routes and 282 stations, spread across 700 miles of roads.

Core characteristics of a BRT system include high-frequency service, extended service hours, routes with a limited number of stops and improved facilities for customers.

About 13% of the proposed network would be in Arlington. The draft action plan spotlights the importance of a few Arlington BRT lines in particular.

For instance, one possible Columbia Pike route — connecting locations along the busy road to Pentagon City and Crystal City in the east and Skyline in the west — could have the third-highest ridership of all proposed routes, according to NVTA projections . The agency estimates that this BRT line would see between 9,600 and 11,600 boardings every weekday, shifting about 900 driving trips to transit.

Another route likely to see heavy traffic would run west from Columbia Pike out to Bailey’s Crossroads and Annandale. In the east, the line would run across the Potomac for a stop in Farragut Square.

A third Arlington route with heavy projected ridership would run across the entire length of the county between East Falls Church and Rosslyn, then jump across the Potomac for a solution that finally connects Rosslyn to Georgetown .

In total, Arlington routes represent about 13% of BRT lines in the NVTA’s proposed vision. About 1% are in Falls Church.

A bit over half of the lines, 52.2%, would be in Fairfax County.

Arlington is already home to one of Northern Virginia’s first BRT initiatives, a 4.5-mile route between Pentagon City and the Braddock Road Metro station in Alexandria. That route is expanding by 1.1 miles this year.

The NVTA is currently collecting feedback on its draft action plan, before the agency’s board of directors considers it for approval later this year. The following “pop-up” engagement events are scheduled to take place in Arlington and Falls Church.

An online form to provide feedback will take comments through May 18.

Hillerich said she sees BRT as a major next step for Northern Virginia jurisdictions seeking to expand their public transit networks.

“This framework is that next step of saying, we have an existing framework,” she said. “Let’s build off of it and give our region more options, past driving alone.”