Transit Tracking

Each year public transportation agencies are challenged with the daunting task of finding ways to make their bus ridership grow; even during a period of economic decline, increased unemployment, high gas prices and funding constraints. Many agencies are using ad campaigns to increase public awareness through Web pages, print ads, radio commercials and TV commercials to try to lure in new riders.

Reliable planning and scheduling, which makes public transportation attractive for passengers and economical for transportation companies, raises many questions. How many passengers get on at stop xy? What routes are most frequented? To find the answers to these questions, a transportation company must count, transmit and evaluate data. In addition, there might be government reporting and other requirements that make passenger counting crucial.

The use of APC equipment for the provision and evaluation of data information regarding actual passenger demand and frequency is of significant importance in conjunction with transit service planning, optimization and applications for funds to improve or maintain operating public transit. It is imperative for a transportation agency to select a system for automated passenger counting and analysis which will allow for the accurate collection of data regarding boardings and alightings at stops, passenger loads of vehicles between stops, vehicle running times and dwell times, and subsequent evaluation of stop, trip and route load analysis.

But how do they determine if they are succeeding? What does ridership data tell us?

There are many reasons that transit agencies collect ridership data, and many uses for the data collected. General ridership information is often utilized by senior management and finance departments while various detailed information such as trip or route level ridership, time of day, and/or stop level data is of importance to service planning and scheduling departments. In addition, location and time-related data is also collected in conjunction with ridership data and used to monitor schedule adherence and an analysis of origin-destination patterns can also be produced.


The traditional way to determine ridership has been to conduct manual ridership audits using people as ride checkers. These ride checkers would spend days riding and recording data such as the current date, time and the passenger counts per stop onboard the vehicle on a select number of vehicles and routes. After the data was compiled, this information was manually entered into a computer program or spreadsheets to mathematically calculate or estimate the overall ridership of the transit system. This information was then used to populate the required forms for the FTA so that the transit agency could apply for funding.

Even though this method has been an acceptable means for agencies to verify their ridership, the time required to collect the data, the quality of the data collected and the ever-increasing expense of using ride checkers has opened the door for agencies to explore alternatives.

Fortunately in today's advanced technological transit environment it is easy to obtain highly accurate ridership data without the need to overspend.


Since the late 1990s Automatic Passenger Counting systems have become a vital component of the Intelligent Transportation Systems (ITS). Reliable APC data supports scheduling and planning departments to improve the on-time performance of their system and provide accurate data to the agency for numerous evaluation purposes.

The advent of the APC systems that will automatically collect ridership data will eliminate the need for time-consuming data collection by ride checkers and the evaluation of the manual counting sheets; as well as the expense associated with all of these time-consuming and costly activities. Thus, allowing for the better utilization of personnel assets.

The basic idea behind these systems is quite simple; some type of sensing device is needed to be positioned so that it can easily and accurately read people as they board and de-board the vehicle. It becomes a little more complicated when you have to decide which type of sensing technology will work and perform the best.

Of the technologies currently available, an infrared sensing device that utilizes the combination of both an active and passive sensing element combined into one sensor head has a proven track record to be perfectly suited for the public transit market.

The combination sensor uses both an active and passive sensing technology. The passive part of the sensor is a pyro-electric sensing unit that detects the heat movement pattern of a person. Pyro-electric technology has many uses in today's ever-changing technology driven world. In this instance for APC detection the movement is detected through the innovative use of "inner" and "outer" curtains projected by the sensors. Each sensor utilizes three individual segments to create the outer and inner curtain. Movement, therefore, is detected when either the "inner" or "outer" curtain is interrupted. Depending on which curtain is interrupted first, will determine if the passenger is boarding or leaving the vehicle.

In addition, the combination sensor also uses an active sensing element, which sends an infrared light to the inner and outer curtain. As soon as somebody passes, the active sensor detects the reflection of the person. The sensor combination detects the direction and how many passengers pass though the door. The sensors are installed above the door, and the width of the doors determines if one or two sensors need to be installed. One sensor can be installed for a door up to 39-inch width. The sensors are connected to an analyzer which compiles the input from the sensors.

Issues can often arise when installing a new APC system within an existing system. Two common issues with APC system installations are:

  1. Finding the optimal sensor location and determining the correct door contact. This can be a little time consuming, but once the proper position and connection are finalized, the system will be ready to provide accurate data.
  2. Another issue is vehicles that have a door hatch that is filled with door activation mechanics so mounting an internal sensor is not feasible. The good news is that this is easily overcome with the use of an external sensor mounting bracket. Fortunately all vehicle configurations can be installed since the sensor integration is flexible due to various types of installation locations, and the setup can be defined via analyzer software settings.


Once the ridership data is collected by the APC system it is in a raw format and contained on the vehicle. To be truly useful to the transit agency this information needs to combined with other information about the vehicle and then transferred off the vehicle.

Within the system the APC analyzer holds this information and passes it to the onboard computer after the door is cycled. The onboard computer stores the count information with the GPS location for the stop. The on-board computer stores all the count information with locations until the vehicle returns to the garage or a location near a wireless access point where the data is automatically uploaded to the server.

It is best to have a vendor perform a pilot installation and only complete the fleet installation after verification of the accuracy. A preferable alternative is for an OEM installation at the factory which yields the best results and highest quality installation.

The vehicles are delivered to the agency with the APC systems already installed, and the agency only needs to conduct a quality check and test rides to verify proper functionality and accuracy.

Once buses started being equipped with APC systems and were able to collect the passenger count data automatically, a new challenge presented itself; how to get the data from the vehicle into the reporting system? Most of the early APC systems relied on the use of some form of removable media storage. This could be a floppy disc or memory card.

Unfortunately; these required manual labor to retrieve and replace, and these small devices were often lost or broken by the people carrying them around. As a result the benefits and value of implementing the APC counting system are reduced.

However, due to advances in wireless computing technology, systems that utilize off-the-shelf, industry standard 802.11(x) devices that eliminate the need for manual involvement in the data transfer process have been designed.


In 2000, APC systems began migrating to automatic data transfer methods to get information to and from the vehicle.

However, the first systems did not have any security during the data transfer process resulting in potential network security problems. Transit agencies were not comfortable with data being transferred over an open network and began requesting some form of secure data transmission. As a result, Init Innovations in Transit, began offering a WEP (wired equivalent protocol) security key developed by CISCO to upload and download the data to the vehicle.

WEP encryption relies on a secret key that is shared between a mobile station (for example, a laptop with a wireless ethernet card) and an access point (i.e. a base station). The secret key is used to encrypt packets before they are transmitted, and an integrity check is used to ensure that packets are not modified in transit. In practice, most installations use a single key that is shared between all mobile stations and access points. The static nature of the shared secret keys emphasizes this problem.

802.11 does not provide any functions that support the exchange of keys among stations. As a result, system administrators and users generally use the same keys for weeks, months and even years.

Today, transit agencies expect to have ITS technologies that utilize the most advanced method of data security. Kyle Brimley, APC project manager for UTA in Salt Lake City, is the first agency to have its vehicles equipped with Protected Extensible Authentication Protocol (PEAP) security standard for the data transfer. PEAP presents a strong authentication method and a dynamic WEP key encryption.

PEAP actually encompasses a two-step process: first the system establishes a secure connection via encryption to create a tunnel, secondly it authenticates the client through a user ID and password system.

At UTA, 41 light rail vehicles have been installed with APC equipment and WLAN equipment for data transfer configured with PEAP standard security. Now, UTA has opted for an additional 28 vehicles to be equipped with APC and the highly secure PEAP. Secure data transfer from and to the vehicle is an important feature for UTA, and more agencies will require such a standard for data transfer in the future.

Init uses a combination of active and passive sensor technology from IRIS to count the passengers getting on and off the vehicles. Of the numerous installations completed, some transit agencies have installed APC onsite as an aftermarket product for current vehicles or coordinated with OEMs to complete APC installations at the manufacturer for newly purchased vehicles. Some transit agencies opt only for APC while others incorporate APC into Computer Aided Dispatch/Automated Vehicle Location (CAD/AVL) systems.

In addition to the vehicle hardware and WLAN infrastructure, the software provides required information for National Transit Database (NTD) reporting. Providing accurate and concise information to the FTA is not only mandatory, but very important. Federal money is decided and dispersed based on ridership trends. The software suite includes a projection module which allows the agency to project the APC data fleetwide. An alternative approach allows agencies to distribute the APC vehicles throughout the service area during the month to obtain passenger counts service wide.


  • * Save money by modifying schedules to suit the customer base. If an accurate counting system is in place, then vehicles can be placed on a route that will best serve the public. Fewer riders will need fewer vehicles. Those vehicles can be placed on a busier route.
  • * Achieving greater accuracy than manual counting. Manual counters can be distracted and therefore, can miss passengers boarding or leaving the vehicle.
  • * Evaluating changes in ridership patterns immediately. Holidays, weather emergencies and more can all affect ridership patterns. Being able to pinpoint where a change is occurring will help to provide excellent and timely service to your riders.
  • * Extensive passenger information reports. Proper reporting can assist in allocating resources properly and thus save your organization money.
  • * Eliminating service where it is not cost-effective. If there is service in an area where there is very little ridership, those vehicles can be moved to a much busier area. Providing service to busier areas will allow for more riders to ride.
  • * Automatic reports for transit funds application.
  • * NTD reporting data.
  • * On-time performance data for training drivers.


Median cost data suggests that a relatively short payback period for investments in passenger counting technologies such as an APC system.

Typical Uses of Passenger Counting:

  • * Compile ridership by the route
  • * Compile ridership by the trip
  • * Track systemwide ridership totals
  • * Compile boardings and alightings stop-by-stop
  • * Monitor passenger loads at the maximum load points
  • * Compile ridership by the day type and the time period
  • * Monitor vehicle schedule adherence
  • *• Analyze origin-destination patterns


The utilization and implementation of an APC system does require proper planning. Getting a solid "buy-in" from all of the affected departments drastically improves the success of the project and the generated results. Therefore it is recommended the following basic steps be considered:

  1. Identify the stakeholders. For example, planning and scheduling departments generally have primary responsibility for all of the aspects of ridership data collection, maintenance and IT will have to maintain the system, and management will want to see the results. These results can help in organizing planning.
  2. A change in passenger counting technology can require upgrades in computer and analytical skills.
  3. Attend trade shows and request information about the technology that is currently on the market. Do your research in advance. Know what technology most interests you and what questions to ask.
  4. Invite vendors for presentations before an RFP is released to the market. This will allow you to see what is available in the market and what can best assist you and your agency's needs.
  5. Think about your reporting requirements. Think about the information that will best help your transportation agency to plan future requirements and scheduling.
  6. Think about security requirements for the data transfer. Consider safety for transmissions and how often the information will need to be transmitted.
  7. Is each stop available in the transportation agency's data base? This includes GPS position.
  8. Start a pilot project to verify the accuracy of the APC system, the data that will be generated and the formatting that will be necessary to help assist your organization.
  9. Have the vendor do a test ride for each vehicle type to improve the accuracy of the system.

Andreas Rakebrandt is an APC project manager with Init Innovations in Transportation Inc.