Interstate 270 (Maryland)

Interstate 270 (Maryland)

Interstate 270 (abbreviated I-270) is a 34.70-mile (55.84 km) auxiliary Interstate Highway in the U.S. state of Maryland that travels between Interstate 495 (the Capital Beltway) just north of Bethesda, Montgomery County and Interstate 70 in the city of Frederick in Frederick County. It consists of the 32.60-mile (52.46 km) mainline as well as a 2.10-mile (3.38 km) spur that provides access to and from southbound I-495. I-270 is known as the Dwight D. Eisenhower Memorial Highway as well as the Washington National Pike. Most of the southern part of the route in Montgomery County passes through suburban areas around Rockville and Gaithersburg that are home to many biotech firms. This portion of I-270 is up to twelve lanes wide and consists of a local-express lane configuration as well as high-occupancy vehicle lanes that are in operation during peak travel times. North of the Gaithersburg area, the road continues through the northern part of Montgomery County, passing Germantown and Clarksburg as a six- to eight-lane highway with a HOV lane in the northbound direction only. North of here, I-270 continues through rural areas into Frederick County and toward the city of Frederick as a four-lane freeway.

The freeway was built in 1953 as the Washington National Pike between Bethesda and Frederick and carried U.S. Route 240, which was rerouted off what is now Maryland Route 355 between these two points. With the creation of the Interstate Highway System a few years later, the road was designated as Interstate 70S along with US 240. There were plans to extend I-70S to Interstate 95 in Washington, D.C. on the North Central Freeway from the Capital Beltway; however, they were cancelled in the 1970s due to opposition from residents in the freeway’s path. By 1975, I-70S became I-270 and the US 240 designation was removed from the road. Increasing traffic levels led to a $200 million widening of the road in Montgomery County to its current configuration and further increased traffic. Many improvements are slated for I-270, including the construction of three new interchanges and the widening of the route between Shady Grove Road and Frederick that would add HOV and express toll lanes.