appendix aassets.stelizabethsdevelopment.com/documents/document... · 2010. 4. 20. · Firth...

TransporTaTion improvemenT alTernaTives

appendix a

The DHS Headquarters Consolidation at St. Elizabeths Final Master Plan

november 10, 2008 - nCpC SubmiSSion Transportation Improvement Alternatives | A-1

The following text is an excerpt from the Final Environmental Impact Statement (EIS) Volume II - Transportation Improvements, DHS Headquarters Consolidation at St. Elizabeths. This text pertains to the access road and interchange alternatives for the St. Elizabeths Campus.

2.C Transportation improvement alternativesFour Interchange/Access Road Alternatives along with a “no-build alternative” (Alternative I-0) have been considered in detail in this EIS. Included in each alternative is the reconfiguration of the intersection of Firth Sterling Avenue/Stevens and Barry Roads to tie into a new access road that would enter the St. Elizabeths West Campus at the northwest perimeter to a gated entrance to the south of the West Campus Cemetery. In Alternatives I-1 through I-4, the access road would then continue south along Shepherd Parkway before tying into a reconstructed interchange at Malcolm X Avenue and I-295. Each of these alternatives are compatible with any of the St. Elizabeths Campus Redevelopment Alternatives, shown in Volume I of this Final EIS.

Two alternatives were considered for improvements to Martin Luther KIng, Jr. Avenue, which fronts the eastern boundary of the St. Elizabeths West Campus, separating it from the East Campus to provide turn lanes for vehicles entering the St. Elizabeths West Campus. The following alternatives for improvements to Martin Luther KIng, Jr. Avenue are compatible with any of the Interchange/Access Road Alternatives described in this section.

Improvements to Firth Sterling Avenue and Martin Luther KIng, Jr. Avenue and construction of the proposed access road would be funded by GSA. It is expected that funding for the Malcolm X Avenue/I-295 interchange improvements would come from other Federal sources

2.C.1 interchange/access road alternativesThe GSA project team worked with DC Department of Transportation (DDOT) and Federal Highway Administration (FHWA) to develop alternatives to improve the Malcolm X/I-295 interchange and construct a new access road from Malcolm X Avenue to Firth Sterling Avenue. At DDOT’s request, GSA assessed alternatives that would improve the traffic situation not only for the DHS Headquarters, but also improve existing deficiencies associated with the I-295/Malcolm X partial interchange, the South Capitol Street/Malcolm X interchange and the main Bolling Air Force Base access gate. The project team developed a total of 11 interchange concepts. Of these 11 alternatives four alternatives along with a “no-build alternative” (Alternative I-0) have been studied in

detail in this EIS. Through consultation with DDOT and FHWA, the following seven alternatives were dismissed:

• Full cloverleaf – A full cloverleaf interchange would extend onto the Bolling Air Force base and its newly constructed security screening area.

• Quarter cloverleaf plus elongated loop ramp – This concept would replace the existing northbound loop on-ramp with an increased I-295 loop ramp and an elongated northbound loop off-ramp. This alternative would push the proposed St. Elizabeths access road east on Malcolm X Avenue and would require significant retaining walls. Also this concept would have greater impacts on the Shepherd Parkway.

• Half cloverleaf with wide diamond ramp – This concept would separate the St. Elizabeths West Campus site access from the I-295 interchange ramps. This alternative would have significant impacts to the Shepherd Parkway since the proposed access road would be located much further east. Also this alternative would require significant retaining wall heights.

• Half tight diamond with site access from ramp – This concept would create an undesirable situation with two-way traffic accessing St. Elizabeths mixing with one-way interstate traffic. Also the access road would require a traffic signal. A traffic signal should not be provided in the middle of an interstate on-ramp when traffic should be accelerating, not stopping.

• Half tight diamond with five leg intersection – This alternative would require confusing and double left-turns at a five-leg intersection. Traffic demands from Bolling Air Force Base would require a double left turn lane from eastbound Malcolm X Avenue onto the I-295 northbound on-ramp. Also a double left turn lane would be required for traffic to turn onto the campus. It would be unsafe to provide double left turns for both legs at this five leg intersection.

• Full tight diamond with five leg site access – This alternative would eliminate the Malcolm X/South Capitol Street ramps and would provide full access to I-295. However, this alternative would still provide confusing left-turns at the five-leg intersection (see half tight diamond alternative above). Also preliminary traffic analyses indicate that this alternative would not operate with acceptable traffic levels due to the close spacing between the two traffic signals that would be required at the diamond ramps.

• Single point interchange with one-way service road – This alternative would only allow one-way access to the St. Elizabeths West Campus from Malcolm X Avenue. This alternative would not meet the access needs of

the campus.

As noted previously four Interchange/Access Road Alternatives along with a “no-build alternative” (Alternative I-0) have been considered in detail in this EIS. Included in each alternative is the reconfiguration of the intersection of Firth Sterling Avenue/Stevens and Barry Roads to tie into a new access road that would enter the St. Elizabeths West Campus at the northwest perimeter to a gated entrance to the south of the West Campus Cemetery. Three alternatives were studied for reconstructing the Firth Sterling Avenue intersection with Stevens and Barry Road to accommodate the proposed access road.

The GSA project team developed alternatives to improve Firth Sterling Avenue. A total of three concepts were developed. Through consultation with DDOT, the following two alternatives were dismissed:

• Five legged intersection – Firth Sterling Avenue would be realigned. This alignment was not compatible with the streetcar tracks that DDOT is constructing alone Firth Sterling Avenue.

• Roundabout – four out of the five streets at the Firth Sterling Avenue intersection would feed in and out of the roundabout, while one street would only feed out. This alignment was also not compatible with the streetcar track DDOT is constructing along Firth Sterling Avenue.

As noted above, a new access road would be constructed from Firth Sterling Avenue into the St. Elizabeths West Campus. In Alternatives I-1 through I-4, the access road would parallel I-295 through the West Campus, continuing south through the Shepherd Parkway before tying into Malcolm X Avenue near the reconstructed Malcolm X/I-295 interchange. The access road has been studied as a three-lane, two-way road that connects from Firth Sterling Avenue, SE to Malcolm X Avenue. The center lane would operate as a reversible lane that would accommodate inbound and outbound peak directional traffic flow. Additional lanes will be provided at the access road intersection with Malcolm X for turn lanes and at the new entrance gate for turn lanes and vehicle queuing for security processing. It should be noted that under Alternatives 4 and 5, it may be feasible to reduce the access road to two lanes, thereby reducing impacts associated with the roadway. If the access road is reduced to two vehicle travel lanes then a bicycle-lane and sidewalk could be accommodated from Firth Sterling Avenue into the campus within the same currently proposed cross section. The bicycle-lane and sidewalk would help provide improved access from the west campus to the Anacostia Metrorail Station, the Naval Support Facility Anacostia (the Naval Annex), and the Barry Farm Redevelopment.

The bicycle-lane and sidewalk would end at the campus limits and would still allow for reduced impacts through Shepherd Parkway to Malcolm X Avenue. GSA would continue to study reductions to the footprint of the roadway and the provision of a bicycle-lane and sidewalk during final design.

To minimize impacts to existing vegetation and steep slopes within the St. Elizabeths West Campus and within the Shepherd Parkway, preliminary designs for Alternatives I-0 through I-4 incorporated the use of retaining walls. Table 2-1 provides an overview of retaining wall heights for each of the alternatives. The surface treatment for the retaining walls would be determined during design and would be context sensitive.

Table 2-1. approximate retaining Wall Heights for interchange/access road alternatives

Retaining Wall Heights

Alt. I-0 Alt. I-1 Alt. I-2 Alt. I-3 Alt. I-4

On Shepherd Parkway south of Malcolm X Avenue

No new con-struc-tion

8 ft to 39 ft

8 ft to 39 ft

8 ft to 39 ft

8 ft to 30 ft

On Shepherd Parkway north of Malcolm X Avenue

No new con-struc-tion

3 ft to 18 ft

2 ft to 57 ft

2 ft to 55 ft

5 ft to 47 ft

On St. Elizabeths West Campus

3 ft to 15 ft

3 ft to 15 ft

3 ft to 14 ft

2 ft to 14 ft

2 ft to 13 ft

Retaining walls with similar heights are located in the District of Columbia along the Southeast-Southwest Freeway at the following locations (Parsons, 2004):

• From 7th Street, SW to 5th Street, SW, an existing retaining wall varies from 7.0 to 20.5 feet in height.

• From 11th Street, SE to 15th Street, SE, an existing retaining wall varies from 14.5 feet to 31.5 feet in height.

• Between 5th Street SW and the D Street Tunnel, an existing retaining wall varies from 7.0 to 22.5 feet in height.

Each of the Interchange/Access Road Alternatives described below are compatible with any of the St. Elizabeths Campus Redevelopment Alternatives, shown in Volume I of this Final EIS.

In accordance with 40 CFR 1502.14 (e) which requires that a preferred alternative be identified in this final alternative is alternative 1-2. GSA’s identification of those alternatives as preferred is based on coordination with, and is subject to, subsequent final determinations of the


november 10, 2008 - nCpC SubmiSSionA-2 | Transportation Improvement Alternatives

Federal Highway Administration and the DC Department of Transportation, agencies that are anticipated to base their approvals in part upon this final Environmental Impact Statement.

Attached is a letter from the Federal Highway Administration (FHWA) that formalizes its Section 4 (f) determination and lends its support to GSA’s identification of the interchange alternative I-2 as preferred in the St. Elizabeths plan, which identification was based on ongoing coordination with the FHWA. It is anticipated that the FHWA’s final interchange alternative decision will be consistent with GSA’s preferred interchange alternative, but the FHWA’s decision it will be made in accordance with the FHWA’s NEPA, NHPA and Section 4 (f) processes as set forth in their letter.

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