ART provides a fixed-route bus service within Arlington County on fourteen routes and carries almost three million passengers annually.

[9] ART's purpose is to supplement the regional rail and bus service provided by the Washington Metropolitan Area Transit Authority (WMATA), providing local bus service, and connecting to neighborhoods, businesses, and departments within Arlington County.

Before ART's inception, WMATA was the only transit agency that served Arlington County, providing both bus and rail service.

Some Metrobus routes served the neighborhoods of Arlington County, connecting them to the Metrorail system.

[12] Route 41 started serving points west of South Glebe Road, including the neighborhood of Arlington Mill.

[13] This bus system served as a feeder to Metrorail stations at the east and west ends of the city.

With the opening of the new bus station, ART and Metrobus began using it as major transfer point.

Since the GEORGE bus system was suspended, the ART fleet run only on CNG fuel.

[21] ART's operator switch went into effect in order to improve service with the on-time performance.

[22] In September 2022, Arlington County began testing electric buses, as part of the plan to go carbon neutral by 2050.

In 2017, ART ordered 13 new 40' New Flyer Xcelsior CNG buses, which are different from its fleet, as NABI discontinued its LFW models in 2015.

[27][28] On June 25, 2017, the iRide SmarTrip Card half-fare program extended to elementary school students, instead of having them paying a full fare.

[29] On May 1, 2023, the iRide SmarTrip Card reduced fare was eliminated, allowing students in Arlington to ride the bus for free.