Occasionally, a signed Traffic Route number does not match the State Route, usually in the case of an extension or relocation. (One example is Pennsylvania Route 3, which uses a one-way pair of Quadrant Routes in Center City Philadelphia.) A different number can also be used to avoid conflicts between different types — for instance, signed Pennsylvania Route 380 is actually State Route 400, renumbered ca. 1973 when Interstate 81E was renumbered Interstate 380. The majority of, but not all, signed Traffic Routes are state-maintained.