Maryland Route 355 (Rockville Pike)

Maryland Route 355 (Rockville Pike)
State	MD
Type	MD
Route	355
Alternate name	Rockville Pike; Wisconsin Avenue; Jefferson Plaza
Length mi	31.64
Established	1927
Direction a	South
Terminus a	Washington, D.C.
Direction b	North
Terminus b	Frederick, Maryland
Counties	Montgomery County, Frederick County

Maryland Route 355 (Rockville Pike) is a major north–south state highway in central Maryland connecting Washington, D.C. with Frederick. The route follows historical corridors such as the Western Maryland Railway right-of-way and the old Rockville Turnpike alignment, serving as a commercial spine through Bethesda, Rockville, and Germantown. MD 355 links with several primary arteries including Interstate 270, U.S. Route 15, and U.S. Route 29, functioning as both local main street and regional commuter route.

Route description

MD 355 begins at the District of Columbia border where Wisconsin Avenue continues from Georgetown into Bethesda; the highway runs north through high-density commercial and institutional corridors adjacent to Walter Reed National Military Medical Center, National Institutes of Health, and the American University. Through Bethesda Row and the Federal Highway Administration environs, MD 355 is lined with retail centers, office towers occupied by tenants such as Lockheed Martin, Booz Allen Hamilton, and medical research institutions affiliated with Johns Hopkins University. North of Woodmont Avenue, the route becomes Rockville Pike, intersecting Capital Beltway at the Springfield Interchange complex and providing access to Washington Metro stations on the Red Line and Purple Line corridors.

Continuing into Rockville, MD 355 parallels the CSX Transportation mainline and the Rockville station transit node, passing civic landmarks like Montgomery County Courthouse and the Rockville Town Center. The highway widens to accommodate commuter traffic approaching I-270; northward the route serves suburban and exurban communities including Gaithersburg, Germantown, and Clarksburg. Approaching Frederick County, MD 355 transitions into predominantly two- to four-lane arterial segments, intersecting with US 15 and terminating near downtown Frederick with connections to US 40 and the National Museum of Civil War Medicine area.

History

The corridor that became MD 355 traces to 19th-century turnpikes and early 20th-century auto trails connecting Washington, D.C. with western Maryland and the Chesapeake and Ohio Canal. The state designated the route in 1927 as part of Maryland’s numbered highway system during the era of the Good Roads Movement and expansion of the U.S. Numbered Highway System. The highway absorbed alignments of historic roads used during the Civil War logistics network and later paralleled the Baltimore and Ohio Railroad and the Western Maryland Railway, facilitating suburbanization in the mid-20th century tied to the construction of Interstate 270 and the I-495.

Postwar growth transformed MD 355 from a rural turnpike into an urban arterial; commercial development accelerated with shopping centers such as the original Hecht Company locations and suburban malls hosting retailers like Sears and Macy's. In the 1960s–1980s, transportation planning debates—featuring agencies such as the Maryland State Highway Administration and regional bodies like the Metropolitan Washington Council of Governments—addressed capacity, transit integration with WMATA, and historic preservation in downtown Rockville. More recently, corridor revitalization initiatives have emphasized transit-oriented development near White Flint and the redeveloped Rockville Town Center.

Major intersections

MD 355’s principal intersections include connections with several federal and state routes and major interstates: the D.C. border matching Wisconsin Avenue, I-495, US 29, MD 187, Montgomery Village Avenue, I-270/I-70 interchange proximities, US 15, and approaches to US 40 near Frederick. Intersections serve multimodal transfers to Washington Metro stations, MARC Train lines at Rockville station and commuter bus services operated by Ride On (bus) and regional carriers.

Traffic and usage

MD 355 functions as a mixed-use arterial with peak-period commuter congestion influenced by employment centers in Bethesda and Gaithersburg, federal activity at NIH and Walter Reed, and retail draws such as the Tower Oaks and Lakeforest Mall commercial complexes. Traffic counts measured by the Maryland Department of Transportation indicate high annual average daily traffic volumes near the I-495 interchange and through downtown Rockville, with lower volumes in rural Frederick County segments. The corridor supports extensive transit ridership on Washington Metro Red Line feeder buses, MARC commuters toward Union Station, and park-and-ride facilities serving I-270 express lanes users. Safety and multimodal conflicts have prompted implementation of bicycle lanes, pedestrian streetscapes, and access-management measures near county urban centers.

Future developments and improvements

Planned and proposed projects along MD 355 span roadway modernization, transit investments, and land-use changes coordinated by the Maryland Department of Transportation, Montgomery County Planning Department, and municipal governments of Rockville and Gaithersburg. Initiatives include corridor improvements to reduce congestion near the I-270 interchange, multimodal enhancements tied to the Purple Line light rail project, and redevelopment of transit-adjacent nodes like White Flint into mixed-use districts influenced by zoning reforms. Federal grant programs and state transportation funding mechanisms have targeted intersection upgrades, stormwater management retrofits linked to Chesapeake Bay restoration commitments, and streetscape projects to support economic development adjacent to institutions such as Walter Reed and NIH. Long-range planning documents evaluate converting segments to bus rapid transit or managed lanes to balance regional freight, commuter, and local access demands.

Category:State highways in Maryland