​(June 3, 2025) – The Maryland Department of Transportation State Highway Administration has closed the merge lane on northbound I-270 that transitions traffic from the local lanes to the main lines of northbound I-270 at Shady Grove Road. The department is maintaining the three local lanes on northbound I-270. Motorists can use the transition from the local lanes to the main lanes of northbound I-270 at the next exit.

The closure of the merge lane is necessary for the next phase of the State Highway Administration’s Innovative Congestion Management (ramp metering) project on northbound I-270 in Gaithersburg. The closure of the merge lane will enable traffic to be channeled to the I-370/MD 200 interchange where a ramp metering system will be installed, which is expected in summer 2025, weather permitting.

Drivers can expect shoulder closures in this area Mondays through Fridays from 9 a.m. to 3 p.m. and until the project is completed. In late June, crews will begin paving operations on the local lanes in this area. Drivers can expect overnight single-lane closures from 9 p.m. to 5 a.m., Sundays through Thursdays.

Ramp metering is a way of reducing overall congestion on high-volume highways where there are many on and off ramps, which cause congestion due to platoons of merging traffic. When ramp metering is in effect, motorists will see a warning sign with flashing beacons. Drivers should be prepared to stop when the beacons are activated, and the beacon turns red. Once the signal turns green, drivers may merge on the ramp and merge with traffic.

Additional information about the project is available here​.