Why Do Hybrid Cars Make That Weird Noise In Reverse?

Hybrid cars, whether they are the Toyota Prius or the Honda CR-V, all come with incredible mileage and provide various unique features. However, there's one feature that you will find common in hybrid cars of most automakers—they all make a weird noise when you put them in reverse. Hearing this sound for the first time could be surprising, as hybrid cars are generally known for not producing any sound while moving. 

Worry not, this noise isn't produced due to the malfunctioning of your car; instead, it's one of the many safety mechanisms installed in your hybrid. As it turns out, due to the low-noise nature of hybrid cars, it is quite hard for people, especially those with visual disabilities, to be aware that there is a car nearby that is reversing. That's why hybrid cars produce that weird noise so that it can alert people around you that you're reversing your hybrid. So, let's learn more about this interesting feature of your hybrid vehicle and what led to its introduction.

According to a report published in The Guardian, electric and hybrid cars are twice as likely to hit pedestrians than cars running on petrol or diesel. While there are plenty of reasons to consider, the silent nature of electric and hybrid cars is the prime suspect according to experts like Phil Edwards, a professor of epidemiology and statistics at the London School of Hygiene & Tropical Medicine. Over time, pedestrians have developed the habit of navigating roads by listening to vehicle noise. But because hybrid vehicles don't make much noise, it's very hard to notice them unless you're directly looking at them.

The situation could be worse when a hybrid car is being reversed and its driver doesn't have proper sight of the back. In such a case, both the driver and the pedestrian wouldn't be aware of each other, which could eventually result in an accident between the two. To avoid situations like this, the Obama administration passed a bill in 2016 that requires all hybrid cars to produce a noise when traveling, both in reverse and forward, at speed up to 19 mph. 

So, you will also notice your hybrids making a noise while moving forward at slow speed, although the intensity of the sound is less compared to when moving in reverse. That said, if you're wondering what exactly this feature is called, unfortunately, there isn't any specific name for this safety feature—Lexus calls it the Pedestrian Warning System, whereas Ford calls it the Pedestrian Alert System, a name that is self-explanatory of what the device actually does.