TAX CREDITS: A program under Federal IRS regulations (Low Income Housing Tax Credit Program) which provides tax credits in return for investment in housing developments where a portion of the units are subject to rent limits for tenants who meet income eligibility requirements.

TDM: See Transportation Demand Management.

TIMED TRANSFER CONCEPT: A concept of transit planning whereby public transportation services are scheduled so that transfer times are minimized at transfer points, typically park and ride lots, transit centers, and rail stations.

TMA: See Transportation Management Association.

TRAILS: A pathway constructed of various materials such as asphalt, stone dust, or natural surface that is used for recreation, or as an alternative mode of non-motorized transportation, or both.

TRANSIT: See Mass Transit.

TRANSIT ORIENTED DEVELOPMENT (TOD): Transit-oriented development (TOD) in Fairfax County is defined as compact, pedestrian- and biking-friendly, mixed-use development containing medium to high density residential, office and retail uses within walking distance of certain rail transit stations identified in the Area Plans. Well-planned TOD should incorporate good design principles and an appropriate mix of uses around rail transit stations to promote transit usage and create vibrant neighborhood centers at these locations.

TRANSIT STATION AREAS (TSAs): The Land Classification System category for areas adjacent to Metrorail Stations (or other future rapid rail stations) which are directly influenced by the presence of access points to the regional rail system. Generally, Transit Station Areas constitute those lands within a primary and a secondary development area. The primary development area is approximately a 5 7 minute walk of a station entrance. The secondary development area is approximately a 15 minute walk of a station entrance. In addition to these general guidelines, Transit Station Area boundaries are strongly influenced by the area's access characteristics and the relationship of the station to surrounding stable neighborhoods.

TRANSIT TRANSFER CENTER: Facility where public transportation services, usually bus services and sometimes rail service, are coordinated so that passenger transfers are facilitated. Facility typically includes passenger waiting and information areas, bus parking areas, and does not including parking.

TRANSPORTATION DEMAND MANAGEMENT (TDM): Actions taken to reduce single occupant vehicle automobile trips or actions taken to manage or reduce overall transportation demand.

TRANSPORTATION MANAGEMENT ASSOCIATIONS (TMAs): Groups of employers uniting together to work collectively to manage transportation demand in a particular area.

TRANSPORTATION SYSTEM MANAGEMENT (TSM) PROGRAMS: This term is used to describe a full spectrum of actions that may be applied to improve the overall efficiency of the transportation network. TSM programs usually consist of low cost alternatives to major capital expenditures, and may include parking management measures, ridesharing programs, flexible or staggered work hours, transit promotion, or operational improvements to the existing roadway system. TSM includes Transportation Demand Management measures as well as H.O.V. use and other strategies associated with the operation of the street and transit systems.

TRIBUTARY STREAM: Any perennial stream that is so depicted on the most recent U.S. Geological Survey 7 1/2 minute topographic quadrangle map (scale 1:24,000).

TSA: See Transit Station Area.

TSM: See Transportation System Management.

TYSONS CORNER URBAN CENTER: The Land Classification System category for the Center that contains a mixture of high intensity office, retail, residential uses and parks (including Urban Parks and active recreation facilities) in a pedestrian oriented urban environment.