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Travel Assistance Device (TAD) to Help Transit Riders
Travel Assistance Device (TAD) to Help Transit Riders
Report Number: IDEA-52
This Transit IDEA project developed and tested a communication application between TAD and an AVL system, to provide new services to TAD users such as estimated vehicle arrival time while they are waiting for the bus, and the display of the real-time bus locations on the TAD website map. This communication supports advanced TAD features based on the real-time location of the transit vehicle in relationship to each rider's real-time location including: providing personalized notices of the estimated time remaining for the bus arriving to current position; notifying riders when their specific bus arrives; and providing the rider with identifying information so that they board the correct bus if multiple buses are present. Many lessons were learned in this project during the integration process between the TAD system and Hillsborough Area Regional Transit's (HART) AVL system in the Tampa, Florida area. Some conclusions reached from these experiences in this project include: Using common values of data attributes (e.g., direction) is very important when exposing transit information as part of multiple datasets (e.g., Google Transit Feed Specification (GTFS), estimated time of arrival web services). Real-time dynamic transit information such as real-time bus position and estimated time of arrival should be exposed to external systems via Representational State Transfer (RESTful) web services for maximum mobile device efficiency and compatibility. Use of cell phone software emulators are valuable to test new software in the development process before deploying to the field, but ultimately the performance of location-based mobile software needs to be evaluated through actual field tests in the real-world environment. The lack of timely transit vehicle location data can restrict some potentially innovative mobile applications, such as the ability to use the vehicle GPS as a backup when the phone's GPS is interrupted. Future transit systems should consider providing timely (i.e., less than 10 second delay) updates as part of AVL system design. The transit industry should consider an effort to standardize the format of lightweight web services exposing dynamic transit information. American Public Transportation Association's (APTA's) Transit Communications Interface Profiles (TCIP) standard should be considered as part of this process to determine if it fulfills the needs of transit information access for mobile devices. Existing web services implemented by transit agencies such as Tri-County Metropolitan Transit District of Oregon (TriMet) in Portland and HART in Tampa also should be reviewed to learn the pros and cons of using TCIP into their current design. If TCIP does not meet these needs, then TCIP should be modified to accommodate mobile devices or a new simple lightweight standard should be developed. For transit systems that are using TCIP standards, a TCIP-interpreter will need to be developed that will allow fluid interaction of the TAD system with TCIP-compliant systems. Cellular carriers must be consulted in order to test TAD on their networks. TAD has been tested on Sprint-Nextel, but was designed to be platform-neutral. Permission from other carriers (e.g., AT&T, Verizon Wireless) must be obtained before testing is permitted. At the time of this report AT&T has provided access to the research team and the team plans to begin testing on this network soon.
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