MD 5 / I-95 Interchange and Metro Access Improvements
Prince George’s County, Maryland
Wallace Montgomery (WM) provided engineering services for the MD 5 Branch Avenue Metro Access Project with a construction cost of $70 million. Services provided ranged from studies through PS&E including highway design, structural design, traffic analysis and engineering, MOT Design, geotechnical engineering, landscape design, H&H engineering, environmental permits, SWM design, erosion & sediment control, right-of-way plats, constructability reviews, IAPA documentation, and support for public involvement.
The goal of the MD 5 Branch Avenue Metro Access Project is to improve traffic flow along the MD 5 corridor, which is a major commuter route from Southern Maryland to Andrews Air Force Base and into DC and multi-modal access to the Branch Avenue Metro Station along with increasing transit oriented development opportunities (TOD) around the Metro station. Project Limits along MD 5 are from Auth Way through the I-95/I-495 Capital Beltway interchange to Manchester Drive. The scope includes improvements along 1¾ miles of MD 5 and I-95/I-495, 2¼ miles of MD 5 & I-95/I-495 interchange ramps, and the construction of a new access road for the Branch Avenue Metro Station and its connection with MD 5. The Project also includes improvements along the adjoining County “Auth” Roadways. The project is being advertised as two separate construction contracts:
Phase 1 – Consists of modifications to the MD 5, I-95/I-495 Capital Beltway Interchange along with safety and resurfacing improvements of I-95/I-495 through the limits of the interchange. The primary elements of the interchange modifications are the construction of a semi-direct flyover ramp from the Capital Beltway IL to MD 5 SB, realignment and construction of the directional ramp from the Capital Beltway OL to MD 5 SB and a cloverleaf ramp from MD 5 NB to the Capital Beltway IL, and the construction of a spur connection ramp from Auth Road to the realigned MD 5 NB to the Capital Beltway IL cloverleaf ramp. The construction of the directional ramp and the flyover ramp includes five (5) bridges, MSE Retaining Walls and a segment of Reinforced Earth Slopes. The Phase 1 Project was a 2009 MDQI Awards Finalist.
Phase 2 – Consists of the construction of a new access road for the Branch Avenue Metro Station and its connection with MD 5 along with the improvements to the Prince George’s County roadway network adjacent to the Metro Station. The primary elements of the new Access Road are the ½ mile reconstruction of the MD 5 NB roadway from Auth Way to Auth Road. The roadway will be lowered (grade cut) for the Access Road to bridge over and create an at-grade intersection (signalized) with MD 5 SB providing dual left turns from MD 5 SB to the Access road and double receiving lanes for the left turns from the Access Road to MD 5 SB.
Key design issues included:
- Geometric Design – Provided geometric design and refinement of the roadways, the interchange, and seven (7) intersections through the use of interchange/intersection traffic analysis and operation reviews and assessments, development of Project design criteria (AASHTO), and constructability studies.
- Geotechical – Incorporation of geotechnical engineering recommendations dealing with ground water tables, construction of high interchange ramp embankments, and design of retaining walls for the interchange ramps and MD 5 NB grade cut.
- SWM/Drainage – Design of combination open and closed drainage systems along with stormwater management facilities to address both water quality and quantity control of runoff. Projects feature SWM “Wet Pond” facilities designed in accordance with NRCS Conservation Practice Code 378.
- IAPA – Provided traffic engineering services to compile an Interstate Access Point Approval (IAPA) request for the interchange modifications.
- MOT Design – Development of construction staging and maintenance of traffic to accommodate the reconstruction / widening of MD 5 and construction of the MD 5 SB double left-in and left-out lanes along with the Access Road bridge overpass of MD 5 NB.