Acoustic warning system AVAS


Fuel cell and e-cars are barely audible, especially at lower speeds, and can pose a significant safety risk. With the AVAS acoustic pedestrian warning system, HELLA has succeeded in taking a significant step towards greater road safety. Find out what AVAS is all about and what advantages this innovative warning system offers.


The key points in short

  • Electric vehicles are so quiet, especially in the lower speed range, that many road users hardly notice them.
  • The AVAS acoustic warning system from HELLA provides more acoustic presence in road traffic in the lower speed range.
  • AVAS is a significant contribution to road safety, and can be customized on request.
  • Starting mid-2021, legislation throughout Europe will require acoustic warning systems for vehicles with alternative drive systems.


Paradox: Electric cars are dangerous because they're too quiet

Less traffic noise is one of the major benefits of e-mobility, benefiting not only road users but also residents and everyone else in public spaces. What is a blessing on the one hand can also turn out to be a curse in terms of road safety. Electric vehicles, hybrid vehicles, and vehicles with fuel cells produce such low noise, especially in the lower speed range, that other road users don’t noticed them at all or only much too late.


HELLA’s technology experts recognized this potential source of danger in road traffic at an early stage and developed a successful solution to the problem with AVAS. The Acoustic Vehicle Alerting System (AVAS) simulates the engine noise of a combustion engine in the lower speed range to alert other road users to an approaching vehicle. If a vehicle with alternative drive technology then moves in a higher speed range, the rolling noise of the tires on the road is sufficient and AVAS is automatically deactivated. Also known as a pedestrian warning, pedestrian alarm, or pedestrian warning system, AVAS can be fitted on not only passenger cars, but also commercial vehicles and vehicles such as buses and garbage trucks.

AVAS pedestrian warning system.

The compact AVAS pedestrian warning system.

While responsible vehicle owners and manufacturers have been relying on an acoustic safety concept with driving sounds for e-vehicles for some time, this accident prevention technology will become mandatory for all new cars starting July 2021. From then on, all new vehicle models registered in the EU must be equipped with an acoustic warning system as a mandatory requirement under EU Decision ECE R138. If a too-quiet car is traveling in traffic at a speed of less than 20 kilometers per hour, the acoustic warning system must give a signal. At speeds above 20 kilometers per hour, the audible warning system for electric vehicles automatically deactivates. In the US, the threshold is 19 mph (30 km/h).

Global noise standards (OICA)

These standards apply worldwide with regard to vehicle noise emissions.

AVAS – for higher safety in road traffic

The AVAS acoustic warning system always goes into action when it is needed. In the lower speed range, the electric engine noise is barely perceptible and is supplemented by an artificially generated acoustic signal that simulates engine noise. If you are traveling in traffic or reversing at less than 20 kilometers per hour, you can rely on the support of AVAS.


HELLA engineers have done a great job in developing AVAS and have brought a technically mature product to the market that meets the highest standards. Weighing only 350 grams, AVAS is light as a feather, and can be used in the wide temperature range between -40 and 85 degrees Celsius. The high-quality electronics are packaged in a dustproof and waterproof housing with protection class IP 6K9K .


AVAS is capable of real-time communication with the CAN-BUS of modern vehicles, ensuring smooth interaction with the other components of the on-board electronics. The sound required by the legislation is provided by a 2-inch speaker with integrated amplifier, which can produce a sound pressure level of up to 86 dB.


In the standard version, AVAS emits an acoustic signal reminiscent of the operating noise of an internal combustion engine. Please find some application examples within the following video:

However, you also have the option to modify the sound according to your individual wishes. In other words, AVAS by HELLA puts you in a position to decide for yourself how your vehicles are perceived acoustically by other road users. Global standards and legislation are always observed.


Electric engines - environmentally friendly and now, thanks to AVAS, safe

The advantages of alternative forms of propulsion are obvious and enjoy great acceptance in large sections of society. Electric cars, hybrid cars, and fuel cell vehicles not only help to protect the environment, they also provide a better quality of life in urban and rural areas.


Where there is a lot of light, however, there is always some shadow. The innovative, whisper-quiet drive technologies can increase the risk of accidents under certain circumstances. AVAS provides added safety wherever the noise of electric motors, which is too quiet, can become a hazard. Thanks to HELLA's acoustic warning system, vehicles can be noticed in good time by other road users in traffic-calmed areas, but also in parking lots, play streets, and when reversing. By supporting AVAS, you are making a valuable contribution to greater safety for all road users.


Would you like to benefit from the advantages of HELLA's AVAS acoustic warning system? More information can be found here.

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