MD 355 Interchange Design-Build

Montgomery County, Maryland

KCI partnered with Concrete General Inc. on this $25 million interchange project that relocated existing Randolph Road slightly south to align with the recently completed Montrose Parkway and provided a new grade-separated interchange at Rockville Pike (MD 355) Montrose Parkway. The construction was necessary to improve safety and traffic flow at the busy Rockville intersection by providing a grade-separated interchange for MD 355 over the connection of Relocated Randolph Road to Montrose Parkway.

The most significant engineering challenges were associated with lowering of the new Randolph/Montrose Road connection under MD 355. The new interchange required a cut in excess of 25 feet, severely impacting traffic, drainage and utilities. The team turned this challenge into an opportunity by using the design analyses as a springboard to investigate all of the project elements and proposed improvements that could be redesigned to save time and materials. The team determined that by shifting MD 355 to the east along the proposed exit and entrance interchange ramps, the west side of the interchange would be opened for preliminary excavation of the new parkway road and construction of the bridge, with an additional benefit of reducing the depth of construction for the storm drain, easier access for utility relocations, and reduced impact to the adjacent park and ride lot.

The improvements addressed the county’s transportation needs for a high volume interchange connection to the recently constructed east-west Montrose Parkway. The interchange—used by more than 55,000 motorists each day—provides additional capacity for development growth in the area while improving pedestrian connectivity to the local shopping centers, apartments, schools, and park-and-ride lots and transit stops. Safety enhancements for both pedestrians and vehicles included reconstructed traffic signals, accessible pedestrian signals with countdown features, sidewalks with new crosswalks and ADA ramps, and a new bike path.