I-495 & I-270 Managed Lanes Study

I-495 & I-270 Managed Lanes Study

I-495 & I-270 Managed Lanes Study


MDOT Recommended Preferred Alternative

After thorough review of currently available information, including the detailed traffic analysis, environmental analysis, financial analysis, and capital costs, and input from the public and resource and regulatory agencies, MDOT SHA recommends that Alternative 9 be identified as the Preferred Alternative in the FEIS for the I-495 & I-270 Managed Lanes Study (MLS).

Alternative 9 consists of adding two HOT managed lanes in each direction on I-495, converting the one existing HOV lane in each direction to a HOT managed lane on I-270, and adding one HOT managed lane in each direction on I-270, resulting in a two-lane, HOT managed lanes network in each direction on both highways.

Apt 9 RPA Image

MDOT SHA’s rationale supporting identification of Alternative 9 as the MDOT Recommended Preferred Alternative (MDOT RPA) are focused on operational improvements, HOT advantages, transit benefits, and environmental conditions, as listed below. Additionally, the alternative will provide new travel options with expanded bicycle and pedestrian connections, including across the American Legion Bridge.

Operational Improvements

  • Alternative 9 will perform the best of the Build Alternatives when evaluating average speed and corridor travel times on I-495 and I-270 within the study area. It is projected to achieve free-flow speeds in the managed lanes while providing average speeds of 41 miles per hour (mph) in the general purpose lanes during peak periods, which is the largest operational improvement of all alternatives studied. One example: Alternative 9 improves average PM Peak travel times from the American Legion Bridge to I-370, from 32 minutes in the No-Build Alternative, to just 15 minutes in the managed lanes, or 23 minutes in the general-purpose lanes, a time savings of 9 to 17 minutes per trip.
  • The improvements in speed and travel time achieved with Alternative 9 will encourage use of the interstate corridors and will reduce cut through traffic on the local roadway network.
  • Alternative 9 will provide the largest reduction in delay on the local roadway network – 7.0 percent delay savings compared to the No Build.
  • Alternative 9 will provide the greatest annual average hours of saving per commuter of the Build Alternatives, approximately 73 hours of average savings per commuter each year.
  • Alternative 9 provides an equitable solution because benefits will be realized by all highway users – those in the managed lanes as well as those in the general purpose lanes, which will remain free.

HOT Lane Advantages

  • Alternative 9 will include HOT lanes that will allow HOV 3+ vehicles to travel free, providing for a more reliable trip in managed lanes, which will reduce dependence on single occupancy vehicles.
  • The HOT lanes will create new opportunities for ride sharing and car/van pooling and support regional planning efforts to expand HOT/HOV lane usage.
  • The HOT lanes with HOV 3+ free will serves as the most operationally compatible alternative with the existing and proposed Express/HOT lane system on I-495 in Virginia.
  • The HOT lanes will provide new equitable travel opportunities and connections because the option for free travel on the managed lanes benefits also extends to HOV 3+ car/van pools and transit.

Transit Benefits

  • Buses will be able to use the Alternative 9 HOT lanes for free.
  • Alternative 9 will allow for the greatest increased travel speed for buses in the HOT lanes by providing free-flow traffic in the managed lanes and assuring a reliable trip.
  • Alternative 9 will provide HOT lane connections to existing transit service on the local arterials that serve the activity and economic centers.
  • Alternative 9 will provide connections that support existing and future transit service to underserved transit markets.

Environmental Conditions

• Alternative 9 will result in preliminary environmental effects that are in the middle of the range of impacts (not the least or the greatest).
• Alternative 9 represents the Build Alternative that received the most favorable comments of those public comments that specified a preference for a specific Build Alternative.

Phase Delivery Approach

  • It is the intent of MDOT SHA and FHWA to work toward implementation of the MDOT RPA through a phased delivery approach with the first delivery phase identified as the most significantly congested area in the PM peak within the study limits- the American Legion Bridge.
  • MDOT SHA will focus efforts on delivering Phase 1 South first. Phase 1 South extends from the vicinity of the George Washington Memorial Parkway to I-270 and along I-270 West Spur to north of I-370.
  • Environmental impacts associated with the MDOT RPA and measures to avoid, minimize and mitigate unavoidable impacts will continue to be addressed for the 48-mile study area and will be covered by one FHWA FEIS and ROD.
  • MDOT SHA will complete additional environmental review of subsequent phases, involving further agency coordination and engagement with stakeholders and the public, before:
    • Requesting permits or authorizations outside of Phase 1 South
    • Seeking transfer or acquisition of public property or pursuing involuntary relocations or acquisition of private property adjacent to the existing interstate corridor for widening outside Phase 1 South
  • The current P3 Solicitation that MDOT SHA has underway is for a partner (called a Phase Developer) to collaborate on preliminary design/predevelopment work with MDOT, agency partners, and other stakeholders to further avoid and minimize impacts to environmental resources, communities, properties, and other features.


MDOT SHA is also committing to incorporate many of the recommendations, comments, and feedback we received from local governments, resource and regulatory agencies, stakeholder groups, elected officials and the public.

Bicycle and Pedestrian Connections

MDOT SHA is committing to priority bicycle and pedestrian connections to remove barriers and provide connectivity for bicyclists and pedestrians consistent with connections identified in the affected county master plans and priorities.

Montgomery County

  • New pedestrian/bicycle connection across the American Legion Bridge
  • Replace and widen Bethesda Trolley Trail bridge crossings of I-495 and I-270
  • Lengthen I-270 bridge over Tuckerman Lane north of Bethesda to accommodate future separated bikeway along Tuckerman Lane
  • New buffer-separated side paths across MD 190 over I-495 near Carderock Springs
  • Widen path along Seven Locks Road under I-495 near Carderock Springs
  • New separated bikeway along northbound MD 355 over I-495 between Bethesda and Rockville

Prince George’s County

  • New 8-foot sidewalks across MD 212 bridge over I-495 near White Oak Manor
  • New 10-foot wide shared-use path plus 5’ buffer along Cherry Hill Road near Beltsvilleon 2 bridges crossing I-495 Inner Loop and Outer Loop to provide trail connection across the interstate
  • New 8-foot wide sidewalks on both sides of Glenarden Parkway over I-495 to improve connection and safety between Glenarden neighborhoods, an identified environmental justice community
  • Pedestrian crossing of I-495 between Arena Drive, Metro Bridge, Central Avenue, and Southwest Branch – evaluate best location for the connection
  • Expand to 8-foot sidewalks on both sides of Auth Road over I-495 to improve access to the Branch Avenue Metro Station
  • New connection to the Henson Creek trail near Temple Hills

Regional Transit Improvements within the MLS Study Area

MDOT SHA is committing to free bus usage of the HOT lanes, which also allows carpoolers and vanpoolers to ride for free in those lanes. Additionally, MDOT SHA is committing to the collaboration and delivery of certain regional transit improvements to enhance existing and planned transit and support new opportunities for regional transit service. These items were noted as priorities by the respective transit service providers and are under discussion with the respective counties.

Montgomery County

  • Bus capacity expansion at WMATA Shady Grove Metrorail Station
  • Park and Ride Expansion at Westfield Montgomery Mall Transit Center

Prince George’s County

  • “Virtual BRT” stops and technology to support their interest in a “virtual BRT” route extension of the Purple Line. This would include stop enhancements and technology such as next vehicle arrival information.
  • A Prince George’s County bus maintenance facility to support their system and the buses that would travel along the managed lanes.

Environmental Commitments and Enhancements

MDOT SHA is committing to continue working collaboratively with our partner agencies to further avoid and minimize community, cultural, environmental, and parkland impacts, and finalize mitigation based on identified priorities that would, at a minimum, bring no net loss to impacted resources with a goal of net benefit. These enhancements include the following:

  • Commit to further collaboration with National Park Service to continue to reduce impacts on National Park Service properties with special focus on areas near the Chesapeake and Ohio Canal National Historical Park, George Washington Memorial Parkway and Baltimore Washington Parkway.
  • Commit to incorporating an option in the MDOT-RPA that significantly reduces impact to the Moses Lodge Cemetery.
  • Commit to environmental enhancements that would provide meaningful benefits to adjacent resources to improve the values, services, attributes and functions which may be compromised including water quality improvements, stream restoration, and removal of invasive species on county parkland.
  • Commit to improvements for stream bank and bed stabilization and removal of concrete lined channels in identified priority areas in Cabin John Stream Valley Park, Rock Creek Stream Valley Park, Sligo Creek Parkway, Indian Springs Terrace Local Park, Northwest Branch Park, Southwest Branch Park, Heritage Glen Park, and Manchester Estates Park.