Volvo's buses are like good children -- seen but not heard, except in times of emergency.

As part of the car company's plan to save pedestrians and the planet at the same time, Volvo has revealed a new strategy to let unobservant walkers know that they're in the path of one of the company's otherwise silent electric buses -- it's called a horn.

Sure, it's nothing novel in and of itself (the car honk is probably the soundtrack to any New Yorker's existence), but the way in which the honk is activated makes use of some pretty cool technology. Known as the "Pedestrian and Cyclist Detection System," Volvo says that its new system "continuously monitors the bus's vicinity using a camera." Anytime the system "detects unprotected road-users near the bus, it transmits a sound to warn other road-users that the bus is approaching," while simultaneously alerting the driver with sound light signals inside the bus. "If there is an imminent risk of an incident, the bus's horn is activated."

Basically, the system ensures that even if the driver doesn't see a pedestrian, the bus itself will. So no need to worry about human error anymore, friends -- our cars have got our backs.

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"Accidents involving buses and unprotected road-users seldom occur, but when they do the consequences may be very serious," Peter Danielsson, Director Vehicle Features and Safety at Volvo Buses, said in a statement. "In order to minimize the risks, it is important that drivers and anyone moving around near buses -- such as at bus stops and pedestrian crossings -- pays close attention to the traffic. In this context the Pedestrian and Cyclist Detection System offers excellent support."

Currently, the plan is to debut the new system in field tests this fall, along with "several other Volvo safety innovations, such as Volvo Dynamic Steering, Collision Warning, and Emergency Braking and Lane Keeping Support," the automaker says. And by 2017, you can expect to find the Pedestrian and Cyclist Detection System on all of Volvo's city buses in Europe.