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Why Automatic Passenger Counters (APCs) Are More Important Now Than Ever

The Lesson COVID-19 Taught Us About Counting Passengers in Public Transit

The COVID-19 pandemic rocked the world and vastly impacted public transit operations. For the first time since the Spanish Influenza Pandemic, public transit agencies urged the public to only take essential trips and put in safety measures to protect both the driver and the passenger by enabling social distancing practices and, in many cases of bus services of onboard fare collection, by going fare-free. These fare-free structures created a reliance on automatic passenger counters (APCs) to count ridership instead of validating with fareboxes. Many agencies quickly realized that not all APCs are created equally as some systems provide more accurate counts than others. Transit agencies could no longer reconcile passenger activity by pulling ridership from fare collection sources, including but not limited to trip sheets, mobile ticketing, demand-response [ADA], TNCs, and NEMT.

“One of the more significant opportunities from the COVID pandemic is being able to identify where our core ridership is truly originating. And without fare collection, measuring core ridership was nearly impossible for agencies without calibrated and certified APC ridership data for fleet vehicles,” said Senior Consultant for TransTrack, Nathan Atherstone.

Automatic Passenger Counters

What are APCs?

“APCs are electronic devices that are typically installed on transit vehicles, including bus and rail vehicles, for providing counts of passenger boarding and alighting activities by stop. They do not directly count such activities. Instead, they have sensors in the vehicle doorways that track the directional movements of passengers as they board or alight,” said Dr. Xuehao Chu, qualified statistician who developed the NTD Sampling Manual.

APCs come with onboard computers that interpret information from the sensors and, depending on the direction of their movements, convert it into counts of boardings or alightings. These onboard counts are finally uploaded and stored in the agency computer system. These stored counts become the raw APC data; the whole process is mainly automated.

Why are APCs critical?

APCs are critical for automatically collecting data on passenger activities that were previously collected manually. Depending on the fleet penetration of APCs, an APC system can provide so much more data, richer data that agencies once either could not afford to collect or could not manually collect the data (e.g., average peak load) but also what they could not do or could not afford to do with traditional manually collected data (e.g., the 95th-percentile value of peak load). Furthermore, large APC data allows agencies to estimate the aggregated ridership or passenger miles traveled with more precision than what is feasible with manually collected data.

The transit industry has realized the critical importance of having APCs. One indication is that the transit industry is quickly moving towards 100% fleet penetration of APCs, at least for bus systems.

“Twenty years ago, few agencies had APCs and, when they did, had deficient fleet penetration levels. By January 1, 2020, according to APTA’s 2020 Public Transportation Vehicle Database, about 60% of all bus vehicles of the 325 responding APTA members had APCs. This percentage was less than one-half of that just ten years ago,” commented Dr. Chu.
The New Website

Why has COVID made APC’s more important now than ever

Traditionally agencies who did not have 100% saturation of APC presence on their fleet relied on other ways to reconcile the data to determine operating costs and passenger boardings. One way to do this is to cross-reference passenger boardings with fare collection. Since the COVID pandemic, many agencies have forgone fare collection to limit transmission of the virus and protect both operators and customers. Safety measures from the pandemic have meant that agencies do not have fare data to cross-reference, thereby relying specifically on APCs or manual passenger counts. Since agencies depend on ridership for funding subsidy calculations, and ridership had already dipped dramatically during the pandemic, it became increasingly important to collect automated boarding data.

Another potential benefit of APC ridership is identifying passenger load. Social Distancing is a primary strategy to reduce viral transmissions, and transit agencies needed to account for accurate passenger spacing during the pandemic. Accurate ridership load tracking was required to monitor passenger crowding and maintain safe practices by dispatching a second vehicle during high use periods.

Although for many agencies going fare-free was only a temporary measure, some agencies have decided to pursue free fare initiatives permanently. Relying on APCs for ridership counting is the long-term solution when transit services decide to go fare-free by policy. Kansas City, Missouri, started making a portion of its bus system fare-free during 2020 and is moving towards a fare-free bus system incrementally over time.

“Fare-free transit is not uncommon for circular services of many U.S. transit agencies. More U.S. cities appear to be exploring the feasibility of fare-free transit,” said Dr. Chu.

What must be done to make the raw APC counts usable?

Having APCs is necessary but not sufficient for improving transit management and performance or for NTD reporting. The raw APC counts, in most cases, are not usable in many instances. According to Dr. Chu, there are two significant reasons:

· The raw APC counts have errors and serious errors in many cases. The raw APC counts must be cleansed: throwing out those operated trips with the most serious errors and correct minor errors for other operated trips with raw APC counts. The cleansing process results in trips with cleansed APC data that is potentially useful for various purposes.

· Many of the operated trips will not have cleansed APC data either because they never had the raw APC counts or were thrown out during cleansing.

“For the cleansed APC data to be really useful for various purposes, the APC system must be validated periodically to ensure the accuracy of the cleansed APC data is within the acceptable limits. Part of the periodical validation is the triennial certification of each APC system by the FTA”, said Dr. Chu.

For generating total ridership from the cleansed APC data at various levels of aggregation, the available cleansed APC data must be scaled up to fill the gap left by those operated trips without the cleansed APC data.

TransTrack Solutions Group will publish another blog that discusses how agencies can use their raw APC counts for both NTD reporting and for their internal needs of increasing their management and performance. Subscribe to our blog list to stay up-to-date on the latest news.

Next Steps
TransTrack Solutions Group works with a qualified statistician to help agencies have their APC system certified by the FTA and produce statistically valid reports for NTD reporting, operations planning, and other internal data needs. TransTrack Solutions Group is here to help support the changing needs of our customers and to support their ridership reporting from all sources to be successful.

No matter what method you use to count ridership for each of your modes, TransTrack Solutions Group can help you. Schedule a discussion with the TransTrack Solutions Group today.

-TransTrack Solutions Group-

TransTrack Solutions Group (TTSG) is home of the TransTrack Manager, a scalable enterprise data management system, serving more than 50 agencies for over 20 years. TTSG prides itself on hiring transit professionals to serve other transit professionals. TTSG can and has managed NTD ridership reporting from all sources. For more information, visit our website at

The authors:
Dr. Xuehao Chu, A qualified statistician who helps you with certification for NTD reporting, and Developer of the NTD Sampling Manual
Nathan Atherstone, Senior Consultant at TransTrack Solutions Group
Kelly Coughlin-Tran, Director of Marketing & New Initiatives at TransTrack Solutions Group


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