AVAS Explained: Understanding the Acoustical Vehicle Alerting System

In the realm of vehicle safety, innovation continues to drive advancements aimed at protecting drivers, passengers, and pedestrians alike. One such innovation is the Acoustical Vehicle Alerting System (AVAS), also referred to as a Pedestrian Warning System (PWS). As a fairly new technology, there are questions that need to be answered. Below we will discuss the purpose, functionality & significance AVAS plays in today’s world of electric vehicle design.

What is AVAS in a Car?

AVAS, or Acoustical Vehicle Alerting System, is an advanced safety feature designed to alert pedestrians, cyclists, and other motor vehicles to the presence of an electric or hybrid vehicle. Its primary purpose is to compensate for the otherwise silent operation of these vehicles at low speeds, thereby minimizing the risk of accidents and enhancing road safety.

How does AVAS work?

AVAS utilizes a sound-emitting device strategically placed on the vehicle to generate artificial sounds that can be heard by pedestrians. These sounds typically resemble those of conventional internal combustion engine vehicles but can be customized based on preference.

The AVAS system consists of a controller and a speaker. The controller can be integrated into the same device as the speaker, or the speaker can be controlled by a separate controller via CAN or other protocol. For example, Seger A.S offers an integrated and separate version, which they call active and passive respectively. Collaboration is typically needed between the AVAS maker and OEM to develop the AVAS system software. They utilize vehicle inputs such as gear position, vehicle status, and gas pedal position to determine the speed of the vehicle, and when the vehicle is moving forward, backward, or stopped. This allows the system to emit sounds when required, which is when running forward or backward below 20 km/h (12 mph). The AVAS system can also integrate features such as over-the-air updates and cybersecurity.

Why is AVAS necessary?

The need for AVAS arises due to the growing popularity of electric and hybrid vehicles, which produce significantly less noise compared to traditional vehicles powered by internal combustion engines. This reduced noise level poses a challenge, especially for visually impaired individuals and pedestrians who often rely on auditory cues to detect oncoming vehicles. AVAS bridges this gap by introducing artificial sounds that mimic the familiar sounds of traditional vehicles, enhancing safety for all road users. It is also now required by law.

AVAS Regulations and Standards

Due to the enhanced safety AVAS provides, its implementation is now required by law. For instance, the United Nations Economic Commission for Europe (UNECE) regulation R138 and the Federal Motor Vehicle Safety Standard (FMVSS) 141require all new electric and hybrid vehicles to be equipped with an AVAS. Similarly, countries such as the United States, Japan, and the European Union have established specific guidelines and standards regarding the design, functionality, and performance of AVAS systems.

In Conclusion

Acoustical Vehicle Alerting Systems (AVAS) have emerged as a vital safety feature by addressing the challenge of reduced noise levels in electric vehicles. AVAS ensures pedestrian safety and helps prevent accidents. The implementation of AVAS globally, supported by regulatory standards, underscores its significance in modern vehicle design. By combining innovation, technology, and a commitment to road safety, AVAS exemplifies the ongoing efforts to create a safer and more inclusive transportation landscape.