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Low-speed automated vehicles (LSAVs) are being deployed in various scenarios to enhance mobility for a wide variety of transportation users. LSAVs are typically highly automated battery-electric vehicles that transport up to eight passengers at speeds below 15 mph on predefined and previously mapped routes. Current applications include providing last-mile connectivity and serving as circulating shuttles in areas such as business districts, military bases, parking lots, and theme parks. An EasyMile EZ10 LSAV was deployed on a route between the Virginia Tech Transportation Institute (VTTI) campus and a nearby bus transit stop as part of a study focusing on prospective user attitudes and acceptance with regard to trust in technology, system safety, and personal security. The LSAV operated on this route within normal travel lanes and interacted with mixed public traffic that included the full range of transportation users from pedestrians to heavy vehicles.

This study evaluated the performance of a new approach for detecting problems with commercial vehicle brakes based on the analysis of sounds emitted during braking. Commercial vehicle brakes emit ultrasonic energy inaudible to humans as part of the friction process, and the spectral distribution of these sounds is highly dependent on the mechanical condition of the brakes. Data collected from a commercial vehicle fleet found that the acoustic signature changes as friction linings wear. This conforms with the acoustic theory that the resonant frequency of an object increases with its decrease in mass. The use of this information to inform maintenance operations is promising in that the scheduling of visual brake inspections could be based on acoustic wear patterns rather than arbitrary time intervals and the observation of anomalous signals that might indicate more immediate concerns.