This map shows various points where the ramp metering will occur. Yellow stars are in north and souhtbound ramps, blue stars are southbound ramps only and magenta stars are northbound ramps only. Credit: Maryland Department of Transportation

Ramp metering began at several exit ramps along I-270 in Frederick and Montgomery counties Tuesday in an effort to control traffic and relieve congestion.

The Maryland Department of Transportation State Highway Administration activated the metering at 23 locations, ranging from Urbana at the northern end all the way down to the I-270/I-495 spur.

For now, flashing yellow stop lights indicate ramp metering will soon be coming, according to a news release.

Around Sept. 15, the metering system will begin, which consists of the following:

  • “When the beacons are activated [and are red], motorists should be prepared to stop at the stop line.”
  • “Once the signal turns green, drivers may proceed on the ramp and merge onto the highway.”
  • “The signal will allow one car at a time to enter the highway, optimizing traffic flow onto I-270.”
  • “Motorists are advised to use caution and reduce speeds approaching the traffic signal as there may be stopped vehicles waiting to merge onto the highway.”

An MDOT SHA video shows how it works.

Transportation Secretary Greg Slater said in a prepared statement that ramp metering is new to Maryland, but a proven tool in other states.


MDOT SHA Administrator Tim Smith said in a prepared statement that metering could help save drivers up to 30 minutes on commutes between Frederick and the Capital Beltway.

The metering is part of a $132 million I-270 Innovative Congestion Management (ICM) Project introduced by Gov. Larry Hogan in 2016. It is separate from Hogan’s plan to widen I-270 and replace the American Legion bridge.

The ICM project also includes “additional auxiliary lanes between interchanges, extension of acceleration and deceleration lanes, and reconfiguration and restriping of existing lanes to optimize traffic operations,” according to the news release.