Site Development Guide - National Capital Planning Commission

INTELLIGENCE COMMUNITY CAMPUS – BETHESDASite Development Guide4.1 Site Transportation PlanningA detailed traffic study for the proposed ICC-B redevelopment was conducted in December of 2010. Thisstudy indicated that transportation improvements could be limited to reconfiguration of the main siteentrance and defined that ICC-B impacts to the surrounding community will be minimal with theseimprovements. The existing site entrance currently has several limitations which impede efficient trafficflow around the complex, particularly during peak commuting times and these will be addressed with theproposed redevelopment.Figure 4.1 shows the configuration of the existing site entrances onto Sangamore Road, the SentinelRoad entrance is the only entrance currently in active use due to security concerns. Sangamore Roadcurrently consists of two travel ways (one southbound and one northbound), with on-street parkingpermitted along the northbound lane. The roadway has a suburban collector character with a postedspeed limit of 30 mph. Sangamore is not a major throughway for the region, and principally serves as aconduit for the adjacent residential areas to access regional arterial streets and highways.Figure 4.1: Existing Site Access, 4600 Sangamore Road, (December 2010 Traffic Study).The 2010 traffic study utilized the McTrans Highway Capacity Software to model the existing conditionsand proposed traffic management alternatives for the ICC-B site. Model runs indicated the existingconfiguration actually performs at an acceptable Level of Service (LOS), even during peak rush hourtimes. The minimum LOS identified with the existing configuration was LOS C, which is acceptable basedon standards for urban roadways published by the Institute of Transportation Engineers.Model input was created based on monitoring existing traffic flows into the facility and on adjacentstreets to record total vehicle movements around the facility on a timed basis. This indicated peakvehicle movements into the site occur between 5:45 and 6:45 AM with an average peak of 528 vehiclesSection 4: Page 1 of 8