SCOPE_OF_SERVICES.docx

PROPOSED SCOPE OF SERVICES FOR TRAFFIC FORECASTING SERVICES

GEORGE WASHINGTON MEMORIAL PARKWAY NORTH DESIGN ENVIRONMENTAL ASSESSMENT

The National Park Service (NPS), with the assistance of the Eastern Federal Lands Highway Division of the Federal Highway Administration (EFLHD/FHWA) and other outside A/E contractors, has initiated the conduct of an Environmental Assessment (EA) for the rehabilitation of the portion of the George Washington Memorial Parkway (GWMP) between the Spout Run interchange on the south and the Capital Beltway (I-495) interchange on the north. During the initial project scoping phase of this assignment, the staff of NPS, EFLHD and the project consultants have identified the potential for the closure of one of the two existing parallel two-lane roadways along this portion of the GWMP to facilitate the roadway rehabilitation construction process.

This purchase order seeks to obtain the services of an organization which can use the currently developed regional travel demand forecasting model structure for the Washington Metropolitan Area to examine what the potential impacts of this potential total closure of half of the existing four lane parkway facility would be on peak period and daily traffic volume movements on the GWMP and adjacent diversion routes in Northern Virginia, suburban Maryland, and the District of Columbia. It is anticipated that some level of network refinements within the modelled study area will be required before the regional travel demand model set could be applied to examine the potential effects of such an action.

This traffic analysis should provide an estimate of the additional vehicles that would detour to the other potential diversion routes on an average day during the period of the full single carriageway closure. An intersection level traffic analysis is not required. The respondents should discuss the potential to provide estimates of potential delay times using the analysis for the full single carriageway closure compared to current operations with all four lanes available for traffic movement and describe any additional analysis that they can perform. Providing delay times across the various construction scenarios being considered is seen as the easiest format to ensure the public understands what the impacts to traffic movement would be from the implementation of such an action.

This work shall be documented at an appropriate level of detail in a project technical memorandum, network graphic plots, and electronic data files. The respondent should anticipate the need to present and discuss this work in no more than two (2) technical work sessions with FHWA and NPS staff.