Vehicle Mass-Based Passenger Counter For Transit Applications


Automatic passenger counters (APCs) provide passenger boarding/alighting information associated with time and location data. APCs are a standard tool used by transit authorities to measure and report monthly ridership to the National Transportation Database with resulting federal subsidies calculated solely based on the data they provide. Additionally, these data provide vital insight into passenger behavior and perception of bus service for purposes of service development. The most accurate APCs currently count 98% of passengers and cost approximately $8,000 per unit (each bus would have at least one unit per door) with cost proportional to accuracy.Buses provide the largest fraction of public transport servicing over 52% passenger trips in the US, and as of 2008 over 840,000 buses were registered nationwide. 

Passenger counter image

With 80% of transit agencies using APC systems and smaller authorities disproportionately using manual counts due to budgetary constraints, a need exists to improve the accuracy of current systems and lower costs. This can be done through systems that integrate with existing hardware and software available on buses such as automatic vehicle location, global positioning systems and controller area network systems that continuously broadcast vehicle and powertrain data.

We have developed a novel APC technology which aims to improve upon existing methods by using vehicle mass to assess boarding and alightings of passengers on transit buses. Unlike the pressure mat methods that only measures mass at the door locations, our system measures the change in mass of the entire cabin derived from three pressure sensors mounted in the vehicle suspension system. Vehicle passenger load is directly proportional to vehicle mass, therefore chances for miscounts can be reduced. With increased integration of existing vehicle information systems, the mass-based APC system has potential for lower cost and could provide additional information of interest to transit authorities like route-specific passenger distribution within the bus or passenger load contributions to fuel consumption.