17 replies to this topic

[Greg Locock]

The National Highway Traffic Safety Administration recently finalized a rule requiring that AEB be included on all new vehicles by 2029.

 

The NHTSA’s ruling will make AEB the law of the land, requiring the feature to stop vehicles to avoid collisions at speeds of up to 62 mph. Braking systems must be able to activate automatically at up to 90 mph when a collision is imminent and 45 mph when they detect a pedestrian.

 

The new rules also require AEB to be effective in day and night lighting conditions.

This has been coming for a while. I wish the AEB in my car was more informative about what it is up to. The slightly related issue with it is the scary noise and graphics if it thinks there is a sideways collision imminent, which I suspect merely means it doesn't know what is going on exactly. Other than that  it seems pretty effective in normal driving as part of the automatic cruise control. Another criticism is that even on max preview distance it does leave braking rather later than I would, which might be a bit of a surprise for whoever is behind me. It is nicely integrated into the trailer software, so it allows more time for a heavy trailer to slow.

 

 

[gruntguru]

I've experienced the opposite in my daughter's Mazda CX-8. A couple of times I have braked fairly late and the system has kicked in with emergency braking (including ABS) before I got a chance to brake. I suppose the system is calibrated to assume a fairly low mu.

[Greg Locock]

Yeah, mu detection is the bugbear of ABS in general.

[BRG]

My Renault Clio is supposed to have this feature but after a year of driving it, I have not had it operate as yet.  Maybe I am just an excellent driver?  No, that can't be the reason!

 

All that I do get is a really really irritating warning - it flashes up in red with the message "BRAKE" generally if it spots a lone pedestrian minding their own business on the sidewalk.  Then the message is gone in a split second before I can even react to it.  Really really pointless and annoying but you cannot permanently disable it. 

 

So I just soldier on as the sole judge of when or whether to brake.  Merci, Renault.

[gruntguru]

Yeah, mu detection is the bugbear of ABS in general.

You mean AEB?

[Greg Locock]

no, I meant ABS. If you knew the mu then you could shape the response better. For example on the Falcon we set the cycle time much slower than is usual, because gravel roads are hard to brake on, and you need to allow a wedge of gravel to build up under the wheel to brake. Obviously this had some impact on normal roads, otherwise everybody would do it. The difference is graphic, I once put a Lexus LS400 in the ditch at a T junction because I braked where I usually braked in an LTD.

[Canuck]

I’ve had the AEB in the QX80 (rebadged Patrol) freak out for no apparent reason on occasion. I assume a combination of environmental conditions and relatively late braking at low speeds. The collision warning seems to be triggered by lane marking lines lit up by the sun at the right angle, on an uphill slope. At normal speeds it chirps it’s warning but the moment passes before it acts. At low / traffic jam speeds it has hammered the brakes in response.

On the flip side, while travelling at highway speeds, a kind human in the slow lane zipped across all the lanes placing himself so close I couldn’t see his taillights. We were all immediately sucked into our seats by the collision prep seatbelt action followed by some aggressive braking. I certainly appreciated it in that moment.

[Bloggsworth]

I was loaned a VW Passat while my Skoda was being serviced; I was driving along an empty road, no cars, no bicycles, not a pedestrian in site, when it jammed on the brakes for no discernable reason - Thank goodness it prevented me from colliding with a shadow...

[Greg Locock]

I've had phantom warnings, but not phantom braking.

[just me again]

Tesla have plenty of phantom breakings in city driving And small roads.

[BRG]

A friend of mine had a SEAT SUV rental in Spain and he said it did a phantom brake on an empty autostrada.  Looks like this tech is far from properly developed.

[Lee Nicolle]

Tesla have plenty of phantom breakings in city driving And small roads.

Tyler Hoover, Hoovie,  You Tuber has just picked up a cartoon truck. Returning to Kansas from Texas the thing braked as it got scared at a steep pinch of road. Luckily g/f April Rose was awake and did not clean him up at 80mph in a 300000 mile Ranger

[desmo]

no, I meant ABS. If you knew the mu then you could shape the response better. For example on the Falcon we set the cycle time much slower than is usual, because gravel roads are hard to brake on, and you need to allow a wedge of gravel to build up under the wheel to brake. Obviously this had some impact on normal roads, otherwise everybody would do it. The difference is graphic, I once put a Lexus LS400 in the ditch at a T junction because I braked where I usually braked in an LTD.

Might it be possible to subtly modulate the throttle in a way that isn't obvious at cruise and monitor the tire rotation to see how it reacts to extrapolate mu in near real time?

[desmo]

A friend of mine had a SEAT SUV rental in Spain and he said it did a phantom brake on an empty autostrada.  Looks like this tech is far from properly developed.

I was driving a rental VW T-Roc in Italy and a couple of times reversing it in tight quarters, it slammed on the brakes so hard that I thought I'd run into something. It felt like a collision.

[gruntguru]

Might it be possible to subtly modulate the throttle in a way that isn't obvious at cruise and monitor the tire rotation to see how it reacts to extrapolate mu in near real time?

I don't think you could extrapolate limit mu from that.

[desmo]

An approximation of it. Longitudinal tire slip in reaction to braking or traction forces. Like I do when I'm trying to get a feel for how slippery a Winter road is by modulating the throttle and brakes.

[mariner]

We have been driving a Chevy Malibu with AEB on vacation in USA. It triggered a full braking when in traffic which nearly freaked out my wife who was driving at the time. She was changing lanes in heavy traffic at under 30 mph. As she accelerated into the left lane space the car in front slowed at an accelerating rate and instant flashing and brakes. Now my wife still has pretty good reactions and she had lifted off ready to brake before any flashing or braking so she wasn't impressed.

 

Having said that I think that AEB may be valuable safety feature in the USA , not because it will emergency brake for an inattentive driver but because it goes off so often.

 

With due respect to any US drivers here and many others, US drivers have terrible anticipation and judgement on segregated highways . They hurtle towards a much slower car at maybe 20 mph closing speed and then brake at the last minute. Or, more dangerous they just swerve left or right into another lane , often right in front of a car or truck. The legality of passing on right or left exacerbates this problem.

 

We have driven in US on and off now for 40 years and its not new. I think that AEB might , hopefully, cure this problem as it will keep going off for such drivers until they learn to look ahead and actually " read" the traffic flow!

Edited by mariner, 12 June 2024 - 22:07.

[7MGTEsup]

I had an ABS stop event in a AMG A45s when a vehicle in front of me turned off the road left but stopped just the other side of the junction. It's not something that I would have even reacted to as they were not on the bit of road I was traveling along. But the vehicle decided that a sharp stab of the brakes was required. Luckily there was no one following me at the time. Not sure the police would believe me if I said the car just braked on its own if it had caused an accident.