Can we stop electric cars from playing music for safety?

I struck a nerve several years ago when I blogged about the horrible beep-beep noise made by heavy equipment when it backs up. Eventually a British company came up with a solution: a pulsed burst of white noise which is very evident when you are near the backing up vehicle but which disperses quickly so it doesn't travel and annoy people a mile away as the beeps do.

Now I am seeing more and more suggestions that electric cars, which run quite silently when slow, make some noise for safety. This is fine, but there are also suggestions that there will be music and vanity noises, like ringtones or "cartones." I can certainly see why this would appeal to people. (Already many think that their car is the place to play mind-numbing bass to announce musical taste to all others on the street.) There are even proposed laws.

While the cartones would be quieter than the backup beep or the heavy bass, I really fear that people will overdo what they think is the purpose -- being attention grabbing. They will want to distract, and that will create a cacophony on the roads. It's hard to make sounds that are meant to be attention grabbing (or vanity oriented) not travel beyond the range that you need them for safety.

I don't want to imagine what it might be like living as I do with a 3-way stop outside my window, with each car singing a different tune or strange noise every time it slows down and starts up again. Who will want to live near intersections or parking lots?

I have a few proposals:

  1. Like the beep-beep solution, use white noise that just doesn't travel very far, but is easily noticed when close.
  2. Use natural sounds, like waves crashing, birds chirping, wind blowing. We are tuned to hear those sounds in an otherwise silent environment, but our brains also can easily ignore them in background form.
  3. Do indeed tune the volume based on ambient noise. This is suggested in the O'Reilly article linked above. They propose it to be loud enough. It should also be quiet enough.
  4. Don't do it at a speed where the tires and wind and electric motors are making enough noise already.
  5. As robocar sensors become more common, such as LIDAR and radar, only make the noise when there are people who might come in contact with the vehicle. Otherwise, be silent.
  6. Since robocars will not hit people in any normal operation, even people who don't know they are there, such vehicles need not make any noise. HOwever, if they see a human or anything else on a collision course, let them make a more loud and useful noise that really gets attention, like a burst of white or pink noise, or even a horn if they ignore that. Start quiet, get louder if it is not reacted to in a human reaction time.

Let's not give up on this opportunity to return peace to our public spaces as electric cars and robocars become popular.


When I first heard the proposals to use 'injected noise' to indicate presence of an EV, the idea was to use synthesized normal-automobile sounds -- a muffled engine, amplified forms of tire noise, things like that. The principal idea being to indicate to a 'user' that an automobile, not an ice-cream truck or somebody with their snarky cell phone ringer turned up too high, was approaching.

I sympathize, of course, with those who want to make some income off the counterpart of ringtones. But I couldn't agree much more strongly that 'cartones' are the wrong answer to any of the questions at hand.

Now, it would be fun to see what happens when UI specialists start working on a set of sounds intended for pedestrians to 'learn' which quiet vehicles would broadcast -- perhaps very loudly -- under certain circumstances. I originally proposed this idea many years ago as a 'modulated horn' to indicate a range of conditions or situations (some of which involved failures in automated-highway systems). In some cases, 'just the right sound' can produce a far quicker response, in just the right ways, than almost any other alerting system.

Reminds me [he says, ruefully shaking head] of the low-coolant alarm on mid-'70s Cadillacs. I can almost see the engineers gathered around the meeting table, saying "suppose we have a little old lady late for her bridge-club meeting, who has a LOCA. What sound can we use that will MAKE HER PULL TO THE CURB AND STOP, even if it's raining, even if she has every excuse to go just a few hundred feet more..." Well, I've heard that sound. I've also heard the master alarm at TMI unit 2. GM's was better! Yes, I knew what the situation was (holes in the heater core)... but yes, I pulled to the curb, and yes, I stopped the engine. *It was THAT good at conveying end-of-the-world alarm... and it didn't have to be particularly loud to pull it off.*

Not saying this would be appropriate as a cartone, of course (except for red-plate Massachusetts drivers, but that's another story... ;-}

Add new comment