Pre-collision alert distance

Well yeah, you look under the hood and there's really nothing to see but a bunch of plastic covers.

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It really does seem that the emergency braking system is really only for emergencies. In my opinion it does allow the car to get "too close" before it kicks in. But, I am used to it now.
I also transitioned from an '08 to the current version. Great upgrade!

 

I went from a Gen 2 to a 2016 Three w/ATP. You can change how far away the system will look. Even on the furthest setting, you still have to get pretty close before the big red BRAKE!! will come on the display.

There is a thread here where someone experienced the pre-collision system in action. The experience sounded scary, but OP was glad to have it. I concur.

Posted via the PriusChat mobile app.

 

curious - about how many settings of variability the prius has. Each manufacture most likely has its own criteria & different setting levels. For example - most teslas we've driven have 7 settings. #7 being so rediculously far away it almost seems like a false warning - as opposed to setting #1 - where you would swear you have already collided, for certain.
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As far as I know, Toyota hasn’t published detailed, quantitative performance specifications for the pre-collision system. The New Car Features book (available by subscription to techinfo.toyota.com) explains how the system works in general terms, but it gives only the same speed ranges that are published in the Owner’s Manual:

• Pre-collision warning:
  • Vehicle speed is between approximately 7 and 110 mph (10 and 180 km/h). (For detecting a pedestrian, vehicle speed is between approximately 7 and 50 mph [10 and 80 km/h].)
  • The relative speed between your vehicle and the vehicle or pedestrian ahead is approximately 7 mph (10 km/h) or more.
• Pre-collision brake assist:
  • Vehicle speed is between approximately 19 and 110 mph (30 and 180 km/h). (For detecting a pedestrian, vehicle speed is between approximately 19 and 50 mph [30 and 80 km/h].)
  • The relative speed between your vehicle and the vehicle or pedestrian ahead is approximately 19 mph (30 km/h) or more.
• Pre-collision braking:
  • Vehicle speed is between approximately 7 and 110 mph (10 and 180 km/h). (For detecting a pedestrian, vehicle speed is between approximately 7 and 50 mph [10 and 80 km/h].)
  • The relative speed between your vehicle and the vehicle or pedestrian ahead is approximately 7 mph (10 km/h) or more.

(This information applies to vehicles sold in regions where pedestrian detection is available.)

As @pilotgrrl kindly notes, the pre-collision warning timing can be changed using the multi-information display. There are three settings, near, middle, and far, but to my knowledge, Toyota has not disclosed how exactly the system’s operation changes for each setting.

For an in-depth, technical look at this topic, not specific to the Prius, I suggest the chapters “Fundamentals of Collision Protection Systems” and “Development Process of Forward Collision Prevention Systems” in Handbook of Driver Assistance Systems: Basic Information, Components and Systems for Active Safety and Comfort, published by Springer in 2016.

 

There are only 3 in my 2016 Prius. I set mine to the furthest away. The middle setting is the default.

Posted via the PriusChat mobile app.

 

Trying to find out what near, medium, and far distances are for the PCS, I've been watching Japanese TSS videos. No numbers mentioned, but I like their music better than ours. Also no tedious legal disclaimers.

Posted via the PriusChat mobile app.

 

It really only responds to true emergencies. I reckon it would have been 3 or 5 months before I got the first " "BRAKE" warning and audio alert" - maybe a dozen times since. On one (maybe 2) of those occasions it "saw" something I hadn't, and stopped in time - savagely.

If it didn't respond ONLY to perceived emergencies, it would be popping up all the time - annoying the driver, who would turn it off - and it would be useless.

The DRCC (Cruise) can be a bit sudden if it detects a sudden closing gap, but that isn't the Pre-Collision alert.

As for looking under the bonnet (hood), there's not a lot which many home mechanics would recognise, particularly on a hybrid. My last car where I would have been able to recognise almost everything under the bonnet was my 940 VOLVO - next car had this massive piece of plastic covering just about the entire engine.

 

I don't think actual distances are used for the PCS, only the relative (delta) speed difference between your car and the object in front...


The DRCC settings are based on actual distances...

 

The youtube videos only show what happened under those circumstances shown.
I don't know the technicalities of it but (stating the obvious, I know) in my experience the "BRAKE" warning comes on when the car thinks you're going to collide if no action is taken. The distance between the object and the time that the warning appears varies with speed, e.g. the faster you're going the earlier the warning (further away) and the system also takes into account the steering angle. E.g I often travel slowly (<20 mph) along a street with multiple parked cars either side, if I am travelling towards one of the parked cars and happen to turn the steering before the warning comes on (to avoid the parked car) the warning doesn't come on, even though I'm still travelling towards the parked car, if I don't turn until the last second the warning appears.

 

I have seen and heard the warning twice but have not had the brakes come on, first I was closing in on a car that was turning off the road, closing speed about 30mph and distance about 40 metres; and second I made a turn across a busy road with a small gap, closing speed momentarily about 40mph and distance about 50 metres. I am not sure that it would have been good in the second instance if the car had applied the brakes.

 

One of the priuschat . com videos on thr Prime's pre-collision system.
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It can depend on the speed your driving at.