The large bridge that carried the Beltway over the trail (before being replaced in 2001) was not built to carry the Beltway over a path; rather, it was built to carry the Beltway over a six lane limited-access highway. That grassy area next to the hospital is not there by accident; it was supposed to be the site of an extensive freeway interchange. The omission of Exit 22 was not a mistake; it was supposed to be the future exit number for the Northern Parkway.
|This was the proposed interchange of the Northern Parkway and the Capital Beltway. Holy Cross Hospital is center left (note the smokestack). Sligo Creek Golf Course is at right. The Beltway is the highway running from left to right, and the Northern Parkway is the one running from bottom-left to top-right. The Boys and Girls Club (building with rounded roof) is also visible along Forest Glen Road. Image from Douglas Willinger's blog "A Trip Within The Beltway".|
The Northern Parkway may have gotten the I-370 designation had it come to fruition, since the road could have been a spur of I-270; branching off of the mainline in Gaithersburg and rejoining it in Silver Spring near the 16th Street bridge over the CSX tracks. The road was called a parkway, but I believe it was to be built to full interstate standards, meaning it could easily accommodate trucks. The word "parkway" may have been used since most of its route runs through Sligo Creek Park, Wheaton Regional Park, and Northwest Branch Park.
|The Northern Parkway running along the railroad tracks and 16th Street through Woodside. The Summit Hills apartment complex can be seen at the bottom. Georgia Avenue is the road running from middle-right to top-left.|
In the end, it's probably a good thing this road was not built. The benefits of a few minutes saved do not outweigh the loss of massive quantities of parkland and the destruction of dozens of homes in a historic neighborhood. Highways are an important part of infrastructure, and they are one aspect of a well rounded multi-modal transportation network. Roads are meant to connect communities, but when those same roads degrade a community's quality of life by destroying parks and private property, they do more harm than good.