Autonomous Emergency Braking - Jaguar I-Pace EV400 Forum
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post #1 of 26 (permalink) Old 06-26-2019, 05:38 AM Thread Starter
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Autonomous Emergency Braking

The Autonomous Emergency Braking does not seem to be working in my car - in over 10000 miles of driving, not once has the car given any indication that it will apply the brakes, even when I have taken it as far as I dare to test it (for instance, I drove at my wife's parked van until I needed to slam on the brakes myself, stopping with only about a foot away from the back bumper). It was one of the myriad of issues I asked the dealer to fix when they had my car for 17 days. They claimed the software is current and the sensors do not show any faults, so as far as they are concerned it is working. When I told them again the car has never responded to any situation, even artificially created ones such as described above, they claimed that they checked with JLR and maintain it is fine because the sensors are not indicating a fault...

I've watched the video promoting JLR's AEB and I have driven dozens of cars that have a version of it and they have all worked (sometimes too well - I was recently driving a M-B B Class that slammed on the brakes as I approached a freshly marked speed bump). My car is definitely not responding like I would expect.

Has anyone had experience with the AEB working as depicted in the JLR video?
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post #2 of 26 (permalink) Old 06-26-2019, 08:42 AM
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I think you may be laboring under a misconception about how these systems work. They are often not designed to, nor are capable of, fully stopping the car before hitting something. They are designed to mitigate the impact of a collision, not necessarily completely prevent it. By way of example, here is a quote from the Euro NCAP test report on AEB: "...AEB activation may not be sufficient or not timely enough to avoid a crash completely, although the resulting impact speed may be significantly reduced."

If you were able to stop the car and avoid a collision, then almost by definition you did not actually "test" AEB.

Here's a report from Car and Driver that outlines their testing of AEB and some overall conclusions, among them were a couple of observations relevant to your experience:
- Many manufacturers are sensitive to false positives as well as to the idea that an over-active AEB may reduce the ability of a driver to take evasive action and so tune their AEB to be less sensitive
- Even from run to run, the AEB systems in the cars they tested did not produce consistent results, sometimes avoiding an accident then hitting the test sled on the next run under the same conditions

https://www.caranddriver.com/feature...ted-explained/
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post #3 of 26 (permalink) Old 06-26-2019, 09:21 AM Thread Starter
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Originally Posted by kkemp View Post
I think you may be laboring under a misconception about how these systems work. They are often not designed to, nor are capable of, fully stopping the car before hitting something. They are designed to mitigate the impact of a collision, not necessarily completely prevent it. By way of example, here is a quote from the Euro NCAP test report on AEB: "...AEB activation may not be sufficient or not timely enough to avoid a crash completely, although the resulting impact speed may be significantly reduced."

If you were able to stop the car and avoid a collision, then almost by definition you did not actually "test" AEB.

Here's a report from Car and Driver that outlines their testing of AEB and some overall conclusions, among them were a couple of observations relevant to your experience:
- Many manufacturers are sensitive to false positives as well as to the idea that an over-active AEB may reduce the ability of a driver to take evasive action and so tune their AEB to be less sensitive
- Even from run to run, the AEB systems in the cars they tested did not produce consistent results, sometimes avoiding an accident then hitting the test sled on the next run under the same conditions

https://www.caranddriver.com/feature...ted-explained/
I am sorry I gave you the impression I was ‘laboring’ over anything. I simply noted it doesn’t appear as if the AEB in my car functions at all, based on my experience in other vehicles I have driven with it.

For reference purposes, I am in rental cars in the US and Europe several times per month. I typically avoid base model minis or econoboxes, so I am familiar with a wide range of various driver assistance features offered by a wide range of manufacturers.

I admit I don’t ‘test’ by accident or on purpose, all the features, especially AEB, every time I get in a car. But I do have experience with them actively functioning. I purposefully ‘tested’ my I-Pace because several months ago a had someone pull out in front of me and I very narrowly avoided a collision without any intervention or assistance from the car and it surprised me.

The dealer had suggested it was a software/sensor/camera issue. So once I got the car back I tested it in a controlled manner and it still doesn’t appear to be working. Take a look at JLR’s promotional video about their AEB. It is touted as able to identify and brake for bicycles and pedestrians. If it is identifying and braking for a car, I am skeptical it would do so for a pedestrian.

I believe others on this forum had indicated they had the opposite problem in which the AEB was overly sensitive. I’m just looking to see what the general experience is.
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post #4 of 26 (permalink) Old 06-26-2019, 10:12 AM
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First thing to remember - AEB will not come on with your foot on the brake or accelerator. Steering will also turn it off. This is so a false signal does not cause a crash. And AEB is intended only for inattentive drivers who are not actively controlling the car. If you drive correctly and sanely, you won't see it.

I have only felt true AEB in Cadillacs during test trials using dummies and inflatable cars. It is 100% max braking, you will feel the ABS pulse frequency, and it stops less than 2 feet from the target.

But I've seen the warning on the Jaguar, Chevrolets, and Cadillacs.

The Jaguar will pop up a message, "Apply Brakes etc" or something, before the AEB takes over. You will feel the brake boost increase. But I've always braked before the AEB triggered.

I like the Chevy Volt system best. It displays six bright red LEDs on the windshield using an HUD projector before AEB engages.

Now the JLR Coffee Cup I don't understand. I'm driving along and it warns me to take a break. I cannot determine what triggers it. In 1,400 miles on a trip, it came on twice.

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post #5 of 26 (permalink) Old 06-26-2019, 11:38 AM Thread Starter
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Originally Posted by McRat View Post
First thing to remember - AEB will not come on with your foot on the brake or accelerator. Steering will also turn it off. This is so a false signal does not cause a crash. And AEB is intended only for inattentive drivers who are not actively controlling the car. If you drive correctly and sanely, you won't see it.

I have only felt true AEB in Cadillacs during test trials using dummies and inflatable cars. It is 100% max braking, you will feel the ABS pulse frequency, and it stops less than 2 feet from the target.

But I've seen the warning on the Jaguar, Chevrolets, and Cadillacs.

The Jaguar will pop up a message, "Apply Brakes etc" or something, before the AEB takes over. You will feel the brake boost increase. But I've always braked before the AEB triggered.

I like the Chevy Volt system best. It displays six bright red LEDs on the windshield using an HUD projector before AEB engages.

Now the JLR Coffee Cup I don't understand. I'm driving along and it warns me to take a break. I cannot determine what triggers it. In 1,400 miles on a trip, it came on twice.
Our Odyssey has a relatively aggressive AEB, applying the brakes in situations where it isn’t necessary. But at least I know it’s working. I’ve driven 3 different Audi’s in the past year that have used their AEB, only one of which I appreciated. As mentioned above, the B-Class I was driving a few weeks ago shuttered to a very abrupt and unappreciated stop from about 10mph as I approached a newly marked speed bump/table that I have driven over hundreds of times previously with no braking interference in other cars.

Given my last experience with ARB and JLRs promotional video of it, it doesn’t appear to work. However it is entirely possible it is working as designed and is simply much less aggressive than others and the the video is not a good representation of it. I’m perfectly fine having a less aggressive AEB, but I would like to know it is functional.
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post #6 of 26 (permalink) Old 06-26-2019, 01:12 PM
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We have had a Cadillac for about 3 years with both forward and reverse AEB. I have only witnessed the reverse AEB come on.
Yet, I have tested the very same model car on a closed circuit and it certainly works.

If the JLR system is like the GM, there is no way for me to tell other than I've received warnings from both systems.
Well, unless I purchase a set of AEB dummy artifacts.
I'm pretty sure the JLR does not have reverse AEB though. It will spot cars, shopping cars, and pedestrians, but I don't think it will hit the brakes automatically like the Caddy does.

We have 4 cars with AEB now and none of them have done a 'false AEB' event. There have been some false warnings though. Not many. You touch the throttle to turn them off.

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Last edited by McRat; 06-26-2019 at 01:14 PM.
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post #7 of 26 (permalink) Old 06-26-2019, 01:20 PM
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Here is ... Uh... Perhaps a XT5? doing a low speed AEB event. It was the only car I filmed, driven by professional racing instructor.

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Last edited by McRat; 06-26-2019 at 01:22 PM.
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post #8 of 26 (permalink) Old 06-26-2019, 03:09 PM
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AEB warning has come up a couple of times when I wasn't paying attention. Made my pulse beat fast!
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post #9 of 26 (permalink) Old 06-26-2019, 04:13 PM Thread Starter
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Originally Posted by bruintoo View Post
AEB warning has come up a couple of times when I wasn't paying attention. Made my pulse beat fast!
What did the car do, flash a warning light? engage brakes?
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post #10 of 26 (permalink) Old 06-27-2019, 04:16 AM
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I've had many warnings while accelerating out of my lane near the back of another car. I've had the brake boosting feature come on unnecessarily.

Photon FE, 2013 FR-S, 2017 RAM 1500, 2014 Forester
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