== Introduction ==
An '''Automated Passenger Counter (APC)''' is an electronic device available for installation on transit vehicles including buses and rail vehicles which accurately records boarding and alighting data. This technology can improve the accuracy and reliability of tracking transit ridership over traditional methods of manual accounting by drivers or estimation through random surveying. These devices are becoming more common among American transit operators seeking to improve the accuracy of reporting patronage as well as analyzing transit use patterns by linking boarding and alighting data with stop or station location.
== Technology ==
APCs work using infared lights above the doorways to a vehicle. A set of invisible (to the human eye) beams of infared light shine down, spaced so that the order in which the beam is broken by a person determines if they are entering or exiting the vehicle. Except in extreme crush-loads the accuracy of this technology is quite high .
The APC computer can also integrate with an on-board GPS system to link passenger data to vehicle location. This provides a wealth of data for agencies to analyze about the utilization of the system based on location, direction of travel, and time.