Every driver has experienced a moment of apprehension upon hearing or seeing an approaching emergency vehicle, especially if he or she was distracted by music, a conference call, or conversation in the backseat. As a result, in many countries, it’s required by law that drivers give way to emergency vehicles. Autonomous cars, in particular, are required to detect and react to varying types of sirens and/or light warning signals from emergency vehicles.
To meet those regulations, BMW Group has turned to Cerence Audio AI to enhance the safety features in its BMW Personal Pilot L3 conditional automated-driving system.
Personal Pilot L3 relieves the driver of the task of driving in certain situations and controls the car’s speed, distance to the vehicle ahead, and lane positioning for them. This option can be ordered for the new BMW 7 Series (excluding the i7 eDrive50 and i7 M70 xDrive), priced at 6,000 euros (incl. VAT) and available exclusively in Germany.
Reaching Level 3
As defined by the Society of Automotive Engineers (SAE), Level 3 automated driving allows drivers to take their hands off the steering wheel and temporarily divert their attention away from the road. The main difference between Level 2 and Level 3 is that with Level 2 (partially automated driving), the driver must be responsible at all times.
Whenever the BMW Highway Assistant is in use, drivers must watch what’s happening on the road and be able to take over the task of driving again. This is continuously monitored using an intelligent attentiveness camera.
Symbols appear on the display behind the steering wheel as appropriate to indicate whether the BMW Personal Pilot L3 is available. It’s activated and deactivated by a button on the steering wheel.
When the function is being used, the customer still has to be ready to reassume the task of driving at any time—i.e., as soon as the situation on the road needs them to, or the stretch of road suitable for using the BMW Personal Pilot L3 comes to an end. If the driver doesn’t respond as required, the vehicle is brought to a controlled standstill.
BMW was granted approval for its L3 tech for use on roads in the city of Shanghai, China in December 2023. Personal Pilot has yet to be approved for use on U.S. roads.
Siren Detection and Driver Notification
Cerence’s Emergency Vehicle Detection (EVD) integrates with the automotive assistant to alert drivers about approaching police cars, fire trucks, and ambulances, prompting them to take necessary action.
The system uses existing microphones to recognize a broad array of emergency siren signals and the direction they’re coming from. Once a siren is identified, the volume of the radio or other media is lowered, and the driver is alerted visually via the head unit and via audio from the automotive assistant.
The technology is said to detect more than 500 sirens from over 150 siren generators that have been collected in 15 different countries, offering a low false alarm rate. EVD can detect siren signals up to a distance of 984 feet using interior vehicle microphones and up to 1,968 feet using exterior microphones.
By using acoustic echo cancellation to remove the music playback from the microphone signals, Cerence EVD ensures reliable siren detection and quick driver notification, even if a driver is listening to a song that includes sirens or other sounds utilized by emergency vehicles.
“As autonomous systems advance, they accelerate a new era of AI-powered companions that seamlessly gather information about the plethora of situations a driver may face in the cabin and on the road so that they can take appropriate action,” said Iqbal Arshad, Cerence’s chief technology officer.
Cerence’s EVD tool automatically detects emergency vehicle sirens and alerts drivers in Level 3 automated-mode vehicles. Part of Cerence’s Audio AI suite, the tool utilizes the distinct sound structure inherent to emergency siren signals to achieve reliable detection of police cars, firetrucks, and ambulances.
BMW’s Personal Pilot can control the vehicle’s speed and determine the appropriate distance between other road users. In addition to Cerence’s safety technology, it uses Live HD mapping to monitor a vehicle’s environment as well as a library of underlying software and a 5G link to the company’s cloud.