Baltimore-Washington Parkway Widening Feasibility Study

Baltimore-Washington Parkway Widening Feasibility StudyExecutive SummaryFEASIBILITY CRITERIATraffic and Transportation – the potential benefits to traffic flow and mobility that can bederived from the additional capacity provided by widening the B-W Parkway.Physical Constraints – the physical limitations for widening the B-W Parkway by a third lane ineither direction including the availability of land and impacts to existing infrastructure,particularly the bridges and interchanges along the Parkway.Preliminary Capital Cost Estimates – the potential capital costs of widening the B-W Parkwayby widening option.Environmental Analysis and Effects – the potential for impacts to natural resources,communities, and quality-of-life in areas such as noise or aesthetics.Public and Political Considerations – the willingness of the public to see a project of thismagnitude move forward.Facility Ownership and Management – widening the B-W Parkway could impair the Parkway’scharacter and function sufficiently to drive a shift in ownership and management from the NPSto the Maryland SHA.AlternativesDefinitionTwo conceptual highway improvement alternatives were identified for the study: widening of theexisting B-W Parkway facility to the inside median area and widening of the facility to the outside rightof-way.Additionally, two separate design options were examined for each of the widening alternativesbased on the different design standards and guidelines used by the NPS and the Maryland SHA forhighway facilities of this nature.The NPS uses design standards and guidelines as noted in its Park Road Standards, published in 1984.The NPS standard for the widened road specifies a new 12-foot lane added to the inside or outside edgeof pavement, an 8-foot outside paved shoulder with curb and gutter, and a 3-foot inside shoulder withcurb and gutter for a total width of 47 feet. The use of these standards helps to preserve the nature andcharacteristics of a Parkway facility. The NPS Outside Widening Option replaces the existing rightshoulder and curb with a new 12-foot lane and an 8-foot shoulder to the face of curb and gutter, whilethe NPS Inside Widening Option replaces the existing left shoulder and curb with a new 12-foot laneand a 3-foot shoulder with curb and gutter.4 November 2012