Electric Vehicle Warning Sounds: Audibility vs. Locatability
As electric vehicles become increasingly common, a critical safety concern has emerged regarding their pedestrian warning systems. While these systems, known as Acoustic Vehicle Alerting Systems (AVAS), effectively emit sounds to alert nearby individuals at low speeds, a new study from 2025 highlights a significant gap: pedestrians often find it challenging to accurately locate the source of these sounds in congested areas. This issue stems from the design of many current AVAS, which produce simple, two-note tones that, unlike the complex sound profiles of gasoline engines, do not provide sufficient directional cues for the human ear. This can lead to dangerous delays as pedestrians attempt to identify the approaching vehicle.
Further investigation into this problem reveals that existing regulations, such as the US quiet-vehicle rule (FMVSS 141), primarily focus on the audibility of these warnings rather than their locatability. This oversight means that a vehicle can pass regulatory tests despite its warning sounds being difficult to place in real-world scenarios, especially when multiple vehicles are present. Recent recalls of electric vehicles, such as the Chevrolet Equinox EV and Mercedes-Benz EQE/EQS, due to issues with alert volume calibration and incorrect reversing sounds, underscore the importance of precise software design in AVAS functionality. These incidents demonstrate how minor software anomalies can compromise pedestrian safety, emphasizing the need for more nuanced sound engineering.
Addressing this challenge does not necessitate a louder urban environment. Instead, the solution lies in smarter sound design. By incorporating broader, textured alert sounds that offer richer directional information, and by aiming these sounds more effectively towards the front and sides of the vehicle, manufacturers can significantly improve locatability. Furthermore, implementing unique sound variations among different EVs would prevent alerts from blending into an undifferentiated hum in crowded settings. Regulators should adapt their testing protocols to include human localization tests, measuring accuracy, reaction time, and failure rates in multi-vehicle scenarios, while also capping confusing sonic similarities. This progressive approach would ensure that electric vehicles communicate their presence clearly and safely, enhancing urban mobility for everyone.
By prioritizing both audibility and locatability in EV warning systems, we can foster a safer coexistence between electric vehicles and pedestrians. This involves a collaborative effort from car manufacturers to innovate in sound design and from regulatory bodies to evolve their testing standards. Ultimately, the goal is to create a harmonious urban soundscape where technological advancements in vehicle safety contribute positively to the well-being of communities, without resorting to excessive noise.