Are Silent Hybrids a Problem?


Some of you might have experienced this as a driver, others as pedestrian or cyclist: Hybrid vehicles, when they operate in electric-only mode, are very quiet, and sometimes people rely on their ears to know if they can cross the street or if a car is about to move. The Mercury News has an article about it. It seems that the extent of the problem is not yet quantified, but frequent enough for people to start wondering if it wouldn't be a good idea to add an "artificial" sound to hybrids to make them a bit noisier. We're not against the idea and would much rather see (hear?) that happening than a debate on the hybrid technology itself (some people will throw the baby with the bathwater at the first occasion), but we also think that pedestrians and cyclist will have to lose some bad habits and use their eyes. That's simply safer.


"This is a reminder for pedestrians that they need to take an active role in protecting themselves,'' said Sean Comey, a spokesman for the AAA. "Some behave as if their status as a pedestrian envelops them in a magic force field that will protect them from an oncoming vehicle. Just because drivers are supposed to stop or swerve or yield doesn't guarantee they will.''

San Jose traffic Sgt. Todd Carpenter agrees.

"In this day and age of iPods, pedestrians should be relying mostly on their eyes and there are many newer vehicles made that are as quiet as a hybrid,'' he said. "Certainly this is something that pedestrians and bicyclists should keep in mind, but I don't see a reasonable solution to this one.''

One Prius driver said that in parking lots, he rolls down the windows and has the stereo playing loud enough to make sure that people hear him.

Traffic officials and police do not know of any cases in which pedestrians were harmed by the popular hybrids. Collision reports don't have a provision for considering whether the quiet nature of the car is a factor. [...]

A hybrid emits less than three decibels of noise when starting up, a level hard to pick up with the human ear. A hybrid clipping along at 35 mph emits 75 decibels -- about as loud as a vacuum cleaner.

What is your experience with silent hybrids?

::Quiet hybrids pose an `invisible' risk