I-270 sign

I-270 sign

​System to Operate on 23 Southbound Ramps at 18 Interchanges

(September 9, 2021) – The Maryland Department of Transportation State Highway Administration (MDOT SHA) will fully activate new ramp meters on 23 ramps to southbound I-270 in Frederick and Montgomery counties Wednesday, September 15, weather permitting. Ramp metering is a part of the
I-270 Innovative Congestion Management (ICM) project to help improve safety, reduce congestion and save drivers up to 30 minutes on their morning commute between Frederick and I-495 (Capital Beltway).   

Ramp metering uses traffic signals and sensors to manage traffic flow entering the highway. The system balances highway demand and capacity, maintains optimal highway operation and reduces congestion for safer, more efficient travel. The ramp metering signals will have the capability to operate between 4 a.m. and 11 p.m. daily and are anticipated to be active during peak traffic hours and when I-270 experiences traffic congestion.   

I-270 Ramp Metering 

Signals at the end of the ramps have been flashing yellow for about a month to alert motorists that activation of ramp metering is coming. When ramp metering is in full operation, motorists will see a warning sign with flashing beacons and should slow down, watch for queued vehicles and be prepared to stop at the stop line just prior to the highway entrance. Once the signal turns green, a driver may proceed and merge onto the highway one vehicle at a time. When ramp metering is not in operation, beacons will be dark and the traffic signals will flash yellow, allowing motorists to proceed without stopping.   

Motorists are advised to use caution and reduce their speeds approaching the traffic signal, as there may be stopped vehicles waiting to merge onto the highway. The system also detects the length of vehicles in queue to help ensure ramps don’t back up onto arterial roadways. For more information and to view a location map and ramp metering video, click HERE.

While a first for Maryland, ramp meters have been used elsewhere as a proven, cost-effective tool to help improve safety and efficiency and reduce congestion. Ramp metering is one piece of the I-270 ICM Project that Governor Larry Hogan announced in 2016 to provide congestion relief and improve travel times throughout the 34.4-mile I-270 corridor from I-70 to I-495. Other elements of the overall $132 million I-270 ICM Project include additional auxiliary lanes between interchanges, extension of acceleration and deceleration lanes and reconfiguration and restriping of existing lanes to optimize traffic operations.

In addition to the 23 southbound I-270 ramps being activated this week, MDOT SHA plans to install ramp metering on another 22 ramps onto northbound I-270 in 2022, for a total of 45 ramps at 18 interchanges by the end of next year.   

The I-270 ICM Project is separate from the New American Legion Bridge I-270 to I-70 Traffic Relief Plan. The ICM Project is aimed at helping improve today’s congestion by eliminating existing bottlenecks and adding intelligent traffic system that will improve reliability and predictability for today’s users. The New American Legion Bridge I-270 to I-70 Traffic Relief Plan will address long-term growth throughout the region. It will transform the corridor by moving more people and goods with less congestion and provide opportunities for rapid bus services, carpooling, new bicycle and pedestrian connections, and the option for single-occupant vehicles is to pay a toll when they need a faster, more reliable trip.   

Phase 1 South: American Legio​n Bridge I-270 to I-370 proposes to replace the 60-year-old American Legion Bridge and provide two managed High Occupancy Toll (HOT) lanes from the bridge to I-270, and north on I-270 to I-370. Phase 1 North: I-370 to I-70, is in the pre-National Environmental Policy Act (NEPA) stage. While separate initiatives, the I-270 ICM Project and the New American Legion Bridge I-270 to I-70 Traffic Relief Plan would work in tandem as part of a multi-faceted traffic relief approach for the region. The I-270 ICM Project provides congestion relief and travel time savings along the I-270 corridor. The New American Legion Bridge I-270 to I-70 Traffic Relief Plan offers a public-private partnership to replace the aging bridge and provide new opportunities for transit and ridesharing, bike/pedestrian connections as well as congestion relief for the National Capital region.

MDOT SHA works hard to maintain safe traffic mobility in work zones for our crews as well as our customers. Drivers need to stay alert, focus on driving and look for reduced speed limits, as well as other driving pattern changes. Please drive like you work here and slow down in construction zones. 

Motorists can dial #77 or 911 on their mobile device for roadside assistance.

For a list of all major MDOT SHA projects, go to Project Portal. Visit our homepage at roads.maryland.gov. For a look at real-time traffic conditions, go to md511.maryland.gov.


Video and other materials related to the I-270 ICM Project are available to the media upon request. Contact MDOT SHA Communications at 410-545-0303 or via email at SHAmedia@mdot.maryland.gov.

Editor’s Note

From intersection improvements to widening and new interchange construction, MDOT SHA is investing in projects to enhance the commute and daily travel for millions of Marylanders.  MDOT SHA maintains more than 2,500 bridges and 17,000 miles of non-toll state roads – the interstate, US and state numbered routes in Maryland’s 23 counties.