Pre-Collision System?

congrats and welcome! all the best.

 

The only button for the PCS is under the steering wheel, to disable the system. You'll need to basically put your head on the floor mat and look up to find it. If you have the radar cruise control, I'm all but certain that you have it. When disabled, the PCS light on the dash will turn on to indicate that it's not working.

And how did the dealer try to test it? By hitting something? The Prius PCS isn't like some of the newer cars that will totally stop before hitting something; you'll still plow right through it, it'll just do some braking before the collision. In 6 years of owning my car, I've triggered the warning a handful of times (where it beeps and the screen says "BRAKE!"), often when I can tell that there's not really a risk. I don't think I've ever triggered the pre-collision braking, but I might've gotten some brake assist once in an emergency stop - I'm not sure if that was the PCS system though, because even non-PCS vehicles can detect some emergency stops based on the urgency in your movement from accelerator to brake pedal. That stop was abrupt, but I really have no idea if it was because I pressed the pedal hard, or because the car decided I needed a little extra help.

In 2010, someone posted a video of them testing out the system by crashing through some empty cardboard boxes. Looks like the video has since been made private, however.

Moral of the story: You'll pretty much never see any evidence of PCS, until you're in an accident. (DRCC is a different matter; it'll give you lots of warnings and such when things are just a little dicey and you *might* hit something. PCS waits until the computer thinks you have no possible way to escape the collision before it takes action.)

 

That's probably for the IPA, Intelligent Parking Assist. I believe some models removed that and replaced it with the Heads-Up Display - does your car have that instead? It was basically a "gee, that's nifty" feature. Unless you are horribly incompetent when it comes to parallel parking, you're better off doing it yourself. The car requires a huge space, probably at least 1.5 car lengths, and generally is a fair amount slower than a human driver. Most of us agree - it's something you show your friends, but never really use. If it worked to fit me into a tiny gap on San Francisco's streets it'd be useful - but that would basically require two consecutive open spaces, so it's worthless there.

Maybe your salesman was confused - I think some of the newer models can detect pedestrians and will come to a complete stop on its own before hitting a car. But the 3rd gen Prius is not as intelligent.

 

Does the cruise control radar have to be on to have the pre-collision system active?

 

Great, thank you.

 

Thank you for explaining. It's good to know.

 

You will know when PCS activates by your seat belt tightening. PCS has never activated in our Prius in the four years we've had it but it has in our Sienna with incredible force - brakes slammed on hard before I got my foot off the gas pedal and the tightening seat belt was literally "breath taking". My chest hurt for a day or so from the seat belt but at least I missed hitting the other vehicle ... by what seemed like an inch.

 

And if the PCS determines that you are an instant from a sufficiently severe collision, it will deploy the air bags a fraction of a second before the actual impact. This is the last step if the emergency breaking is not sufficient. And as mentioned, the seatbelts will have been tightened.

Note that this system is different from the feature in the DRCC where it flashes the multi-purpose display and squawks if if feels you are approaching the car in front of you too quickly. This happens so often to me when using the DRCC in highway traffic, that I just take it as a "heads up" to use the brakes to slow down. I have never experienced the PCS system, and have no desire to.

 

No, it waits for the deceleration to start, just like any other car. In fact, each of the airbags require at least two accelerometers to exceed the set value before the computer will deploy the airbags. Doing otherwise would be dangerous if it were wrong, and the detection mechanisms used by the airbags are sufficiently speedy (and the crumple zones of the car are sufficiently squishy) that they don't need the head start. Additionally, not all types of collisions will trigger an airbag deployment, so it uses the accelerometers to determine if deploying the airbags is appropriate.

The PCS will tighten the seat belts, apply the brakes harder than you ask it to, brake even if you don't, and I believe can also pre-charge the brake system.

I hear rumors that next year's model will also back up the text message you were writing on your phone when you got into the accident in the first place.

 

Oops. Guess I misread something somewhere somewhen.

 

I fail to see the humor. I was lucky to be able to walk away - just barely and in a lot of pain - each of the two times a vehicle I was driving was hit hard in the rear while I was completely stopped in traffic. It might have been much worse if I had been driving a little Prius but each time I was fortunate to be driving a much larger Lexus LS sedan although not the same one. Both times I declined medical attention and recovered on my own over time. Both times, the damage was just below the threshold where my cars would have been "totaled" for insurance purposes and it took months for my cars to be repaired and to get them back.

If the vehicles that hit me had been equipped with PCS or a similar technology, maybe all of us could have avoided the pain, expense and inconvenience.

It is unfortunate that it is going to take so long but at least automatic emergency braking is going to become standard: Automakers agree to put automatic braking in cars by 2022 | PBS NewsHour