"Pre-collision braking"--will Prius v with ATP come to a complete stop? 5-16-14

It does if it hits the obstruction.

 

Short answer: no. Long answer:

The Insurance Institute for Highway Safety (iihs) just published the results of its tests of vehicles for this safety feature. The answer is that some do it well, others not so well. I know that the Prius v five with ATP did not meet their minimum criteria, as I now own the test vehicle. (A family member works for iihs and the institute buys their test vehicles and for ones that are used for non-destructive testing, they are offered for sale at good prices to employees...)

I can tell you that the damage done to the Prius v in its "failing" of the test didn't result in any structural damage, nor anything you can see from >10' or so. Of course, that was into their stationary target (a picture is found at the first link, coincidently with a Mercedes), which is not a car, so ymmv.

Here is a link to the article on the testing:
Status Report

Here is a link to the Prius rating:
Vehicle details


The only mention that is made in the public article is:

Like I said, I drive the car. I'm not concerned as this is a new thing aimed at crash avoidance. Some folks have figured it out. Others haven't.

By the way, the Subaru system worked the best in the tests. My first car out of college was a Subaru, and the technology content of that car was exactly zero, so they've come a long way. (Heck, it didn't even have a/c.)

 

I don't perceive the system as being intended to prevent a collision, but simply to mitigate the damage. I already view it as somewhat intrusive. If it was braking soon enough to stop completely before a collision, it would be much more intrusive, and frankly I wouldn't want it. As is, I trust it to slow me down (if I'm just not paying attention) and lessen the impact. I don't really want a car that comes to a screeching halt and prevents me from taking some avoidance action. Slamming on the brakes isn't always the best solution. As it is, the system screams at me before it actually starts braking, and there's enough time for me to take whatever action I choose. I think its engineered pretty well.

 

I agree with the above comments. I don't want the car to brake to a stop. The only conceivable use for me would be if I had a heart attack (or similar) and was incapacitated. Driving in fog or other adverse environment bad enough to support a full stop means the driver should already be off the road - IMHO.

BTW, while traversing Nashville highway construction, during rush hour, I had the opportunity to witness the system in action. It managed to put the brakes on before I could get to them. And yes, I was driving too close to the vehicle in front of me, and too fast for conditions, but it seems somewhat expected/normal for rush-hour traffic

 

Toyota PCS is intended only to reduce the speed at impact in a crash - maybe it should be called the "Pre-Crash System" as it is called in the U.K. to make its purpose clear. Simulation videos on European Toyota websites make it clear that a vehicle with PCS will crash into a vehicle if a driver does not apply the brakes on his own.

I find it interesting how the PCS in our Prius v intervenes late and not very forcefully when I intentionally invoke it. PCS in the Sienna van we bought a few weeks ago seems substantially more forceful when I intentionally cause it to intervene. In neither vehicle have I gone so far to cause the seat belt tensioners to retract - that must happen in the split second just before impact which I am NOT going to attempt to simulate since, besides being dangerous, could require replacement of the seat belts.

 

my only complaint is the warning buzzer is not loud enough and would like it to keep buzzing until the brakes are applied by the driver.

 

Toyota's system SUCK BALLS. Why spent millions on research and do a half nice person job. Rear ending someone at 35mph is not any better than rear ending someone at 45mph. In the end, you still rear ended someone. You say you want control. Given that you weren't paying attention in the first place when you approach a stopped vehicle, Toyota's system warns you but your reaction time has been delay passed the point of stopping in time. Yeah, you were in control when you hit the car in front of you. Nice control there.

I have personally experienced PCS recently. The system did warn me. Luckily, I reacted in time to stop the vehicle. I can tell you that that reaction time is very short, less than 1/2 second. What if I didn't react fast enough? I would have rear ended the car in front of me.
PCS should work like DRCC on steroids. The system beeps with dash warning and brakes with full force for you and continues to brake until either it comes to a complete stop or senses brake pedal pressure from driver and let the driver take over. If the driver is not braking fast enough, PCS takes over again until complete stop or until impact. PCS should stop the vehicle with room to spare to compensate for different tires' brake performance.

If you look at Subaru's EyeSight demo videos, most will stop before impact. Some will still make contact with obstacle but at a very slow speed.

 

What if it caused the vehicle behind you to crush the rear of your car?

With my experience, it was a turkey that triggered the pre-collision response.... something which would have caused far less damage than getting hit from behind. There's a small chance of swerving around it too, if the vehicle is still moving.

I did like the fact that the car tightened the seat belts, pulling us both back into better positions for an impact.

 

That slowing produces a 40% reduction in collision energy, a sharp reduction in injury and mortality potential.

Anything advertised as a 'full-assed job' is going to prompt more drivers to turn their brains away from the road, or even completely off, and trust the machine do the work.

But these systems are not even close to the accuracy and reliability needed to allow drivers to relax their attention. A 'full-assed job' demands something very close to actual autonomous vehicles, costing a lot more than mere 'millions on research'. Those are coming, but they are not yet here, at least for the civilian consumer market.

 

Then the vehicle behind you is following too close and not paying attention. I have seen many times where the car in front of me weren't paying attention to the road and slammed on their brakes to avoid collision. Because I was paying attention to the 2 cars in front of me, I was able to slow down normally without slamming on my brakes.

I know it slows down and reduces collision energy and reduce injuries but why only reduce? Why not eliminate? Eliminate the repair bill and medical bill all together rather reduce the repair bill and medial bill. Actually it's not that much reduction. You're still gonna have to pay the full deductibles regardless of collision speed. I'd rather walk drive away unharmed from a none existent traffic incident than walk away from a 35K brand new totaled car.
Airbags save lives. Do people drive more recklessly knowing that the airbags will save them from a collision? I don't believe full braking PCS encourage people to pay less attention to the road. I sure don't drive recklessly knowing I have PCS.
It doesn't cost a lot more millions on research for a full assed job. Are you telling me that Subaru has deeper pockets than Toyota?

 

Just so everyone understands, the amount of work being put into this right now across the globe is enormous. Crash avoidance technologies is the sexy auto safety thing in the industry and is being worked from Munich to Nagoya. And the idea is to have the car stop. Full stop. And at the same time, not ever stop autonomously unless it needs to.

Again, some folks are closer to a workable endpoint than others. And, as you might expect, those that still have issues to work through, #1 still want to deploy something (for both marketing and field experience) and #2 err on the side of doing too little rather than too much - being no one wants a car that incorrectly stops on its own. That seems to be where Toyota is. I'd really recommend avoiding judgment about the technology without experiencing the best of the lot, eg., Subaru and Mercedes.

 

Because the industry simply isn't there yet.

Yes. It is called 'risk homeostatis' or 'risk compensation'. It is part of the reason seatbelts, ABS, VSC, and other safety features don't save as many lives as they should.

I have a new 2014 Subaru for which EyeSight is an available option on a higher trim level. The product brochure makes crystal clear, to anyone with any reading comprehension, the it isn't a full-assed job. The driver is still responsible.

As soon as some humans start thinking that these systems eliminate injury, they will begin relaxing their attention and hand over some responsibility to the machine. But unless the machines are fully qualified for autonomous operation -- none of the commercially available pre-collision systems are -- they cannot eliminate injury. The legal liability issues here are enormous, and unresolved.

 

As an engineer who contributed to the international standard on such collision avoidance systems, I can fully agree with this interpretation. It is difficult and expensive to build a triggering algorithm that will reliably provide full stop when the driver thinks it should and never provide it when the driver thinks it should not. It's hard, requires more forward sensors than just a camera, and needs a lot of field experience before it can be fully trusted and delivered to the general public as a product. Not all drivers have the same expectation of the product. US highway-speed rear-end collisions are not the only major use case for an international product - some large nations have most of their rear end collisions below 35 mph even on limited-access highways. It's actually pretty amazing that Toyota has made the system an available option at levels lower than Lexus. I would rather have the one that is available than have none.

I would like to read the IIHS standard. I wonder if they set a criterion that is higher than that in the ISO standard?

 

Unfortunately, I can't post more than I have. I don't doubt that you could get ahold of the test protocol though if you are tied in to the standards side of things. UMTRI might be a good source up there in MI. (As would the auto companies of course.)