Oh my. Of all the problems to spend research time on. I\'m sorry to be so cynical. Worrying about people being run over by EVs is like worrying about Canadian spy networks.

I want the \"Cow Bell\" option.

IDIOT RESEARCH. Trains..... must have a man walking in front of it with a red flag! Remember that!
So now we have to create artificial noise pollution because some idiot can think of 10 reasons how they can get run over. Atattch a smog machine so we can have the stink as well. It\'s all to much for the human unit. Anyroad Gizma the best little email you can get.

The simple answer is to just force the cooling fans to be on when the vehicle is traveling at less than 15mph. The fans are most of the noise you hear on a modern IC-engined vehicle at low speed, anyway.
Adding a noisemaker (which can break, and will almost certainly be \"modified\") is a terrible idea.

In the long run, whether vehicles are gas or electric, a better solution would be to generate targeted sound (for example, with a beam-forming speaker array) directed at people in or moving toward the space that the vehicle is about to occupy. For example, suppose the vehicle is approaching a crosswalk and is too close to stop before the crosswalk. Using on-board sensing (lidar, vision, etc.) the vehicle detects a person stepping into the crosswalk, and predicts a collision. Reacting in a few milliseconds, it generates a sonic \"slap\" focused right on the person\'s head. Sound, traveling at ~750mph, reaches its target quickly, giving the person a few hundred extra milliseconds to jump out of the way.

As a regular commuter cyclist, I DO NOT rely on vehicle sounds. Most vehicles emit most sound from the rear and my ears are aimed to the front. I don\'t hear cars until after they pass me. In the winter, I have a hat down over my ears and hear even less. I just use a mirror to see what\'s coming. I participated in the evaluation, but I too am offended that EVs need to make artificial noise. That reduces the efficiency, for what gain?

I like B. It sounds like the sci-fi vehicle I\'ve always dreamed of driving. I think the sound should be something between a standard combustion engine (for familiarity) and an electric hum or whir. Basically an amplified and throatier version of the sound the motors make naturally.
Simply put, it should sound like the sexiest version of the future imaginable.

It would be inspiring to read more comments from people that understand the very real hazard silent vehicles present. While I don\'t doubt that some of those commenting are very \'tuned\' to their environment and can\'t imagine not noticing an approaching vehicle, there are many who do rely on hearing, along with other senses. I drive a prius and try to be particularly vigilant about pedestrians and animals. There have been several occassions when my silent approach has been unnoticed and an accident narrowly averted.

Several observations: In response to those who ridicule the idea of the need for some kind of noise, I am both an electric vehicle advocate and the \"victim\" of an electric sneak attack. The main place the noise is needed is at low speeds, before the tires make enough noise to be noticed. I was bumped by an EV at an electric vehicle demonstration after I stepped out in front of it in the parking lot. I was barely bumped but had the driver not stopped right away I might have been seriously hurt. My mistake, but there were no sound cues. Any noise might have helped, so I support the idea of sound generators.
Also, Robert mentioned that he does not rely on sound while riding. I am also a cyclist, and for right or wrong, use my hearing as well as mirrors to sense traffic to the rear. At highway speeds, a car makes enough tire noise to be heard quite easily from hundreds of meters away. This would apply to electrics as well. Ears should have no problem sensing sounds to the rear.

Stick a baseball card in the spokes! Maybe people should just pay attention to their surroundings. With this logic, every electric car or motorcycle, bicycle, tricycle, person, dog, cat and squirrel should also have a noise generator permanently installed. They have a large number of electric cars and utility vehicles on the campus where I work. Other than the rate at which they\'re driven, I have not had any problem with their low noise level.