Some of the foundations are located in confined spots adjacent to I-66 and the electrified third rail of the Orange Line, making access difficult. Dulles Transit Partners offered to inspect seven foundations that were easily accessible, but the FTA insisted that all foundations be tested. Dulles Transit Partners and MWAA agreed to test all foundations before the bridge piers were built upon them. This required the portion of the Orange Line between the West Falls Church and East Falls Church Metro stations to be taken out of service on weekends while the tests were conducted. All foundations were acceptable and the bridge construction proceeded using the existing foundations.