If you press the power button on a Toyota Prius while in motion will it shut off the engine, or take it as a mistake?

This link may be of interest.

You could turn it off, but you also lose power steering that way.

Of course losing power steering is immaterial, as you can still steer without power steering. It may be like steering a tank, but you can steer.

I think putting the car in neutral would be better, because all the ‘power’ stuff stops working when the power is turned off, including the brakes. A small person like myself would be literally helpless trying to turn or stop – I know, because I’ve tried driving a ‘power everything’ car with the engine off.

This should be an easy test for anyone who owns a car with a start/stop push button.
You don’t have to do the stuck accelerator test. Just drive 30 mph on a straight road and try to turn the car off by holding the button.
Anyone willing to try? Please let us know.
Loss of power steering is no problem. You’re not trying to parallel park.

It’s been proven, and now reproven by @laureth‘s video, that the brakes alone will stop a car with a mashed accelerator. All the incidents with Toyota vehicles recently ended badly only because the drivers panicked and did not think straight.

@Fred931 Yep. Too bad proof and facts don’t matter today’s society; it’s all about sensationalist headlines, scandals, and lawsuits. I mean, Gawd forbid we should actually know how to drive when we can just blame someone else for our actions. Competence and accountability don’t sell papers, get viewers, or garner pity, but if you just lose your shit (or were an idiot to begin with) and can pass the buck, that is golden!

@YARNLADY That depends a bit on the vehicle, but every vehicle lost power steering in (and the few that never had it) were all easy to steer at any speed fast enough to dent a fender even though I am not exactly strong. They were a bit tricky in parking lots, but if you have the strength to close the door hard enough to latch then you can steer most cars that lose P/S. Even those that have so much assist that they offer so little feedback that you should not drive them on anything other than dry asphalt.
I drove a couple of cars that had such a strong power assist to the steering that I thought I was playing a video game. Nearly got me killed when the roads got slippery too; anything like snow, rain, dirt, gravel, concrete, or anything like that, but I managed. It just took both hands instead of one finger.
As for the brakes, there is enough vacuum left to stop once. Maybe twice if you’re lucky, but probably not. Been there, done that.