An Acoustic Vehicle Alert System (AVAS for short) is an acoustic warning system for low-noise vehicles, especially electric cars. Since the 14th generation of Ford F-150 now has hybrid drive, it is equipped with such a system, called Pedestrian Alert System.
This is an artificially generated sound that resembles an internal combustion engine. It is emitted at low speeds to inform road users about the vehicle. From a speed between 20 mph and 30 mph, the rolling and wind noises of the vehicle are loud enough to take on this role.
In the Pedestrian Safety Enhancement Act of 2010, which went into effect January 4, 2011, the United States Department of Transportation was tasked with regulating alarm sounds in motor vehicles to protect blind and other pedestrians. The draft submitted by the National Highway Traffic Safety Administration (NHTSA) in January 2013 set the threshold to a speed of 18.6 mph. The NHTSA estimated that this measure could prevent 2,800 injuries per year.
On the part of the automobile manufacturers, there were objections such as the one that the noise is only necessary up to a speed of 20 mph. After several delays, the final regulation was adopted by the NHTSA in February 2018. The implementation by the vehicle manufacturers and importers completed by September 2020.
Pedestrian Alert System on Ford F-150
According to Ford F-150’s owners manual: “Due to the quiet operation of hybrid and electric vehicles at low speeds, the system creates a subtle sound to alert pedestrians. The system is on when your vehicle is running and not in park (P). Some sound may be audible in the passenger compartment.”