Rear ended twice in 3 months.

[Peteski]

The rate of deceleration determines whether the brake lights illuminate.

That's what I've observed too. My brake lights illuminate when decelerating under regeneration only, but only once the rate of deceleration is higher than you would typically get from just lifting off in an ICE car. But the trigger setting seems quite conservative with brake lights coming on under pretty light regeneration braking. So I don't think this is a factor unless some cars have faulty brake lights or sensors and are not working properly.

AP often brakes quite aggressively when approaching slower traffic at highway speed, so I'm always wary of that if someone is close behind at the time. In slow stop start traffic AP is also a little slow off the mark, so there is potential for someone to run into you if they are watching the line in front and you are slow to start moving. But ultimately I don't think AP is a big factor either.

As usual it's really down to the many incompetent drivers on the roads, although the UK is not so bad in that respect and thankfully it is quite rare to get rear ended in traffic. It's only happened to me once in decades of driving and that was on an icy road where the car behind skidded and slid into the back of mine (not the Tesla luckily!)

 

[Krazaak]

The rate of deceleration determines whether the brake lights illuminate.

Just to elaborate.

If you’re stopped with auto hold activated, brake lights are on.
If you’re depressing the brake pedal, brake lights are on.
If you’ve completely let off the accelerator with standard regen, brake lights are on.
If you’ve let off the go pedal a little and are slowing down, brake lights may not be on.

 

[markb1]

If you’ve completely let off the accelerator with standard regen, brake lights are on.

This is usually true, but I find when going very slowly, that's not the case.

 

[Krazaak]

This is usually true, but I find when going very slowly, that's not the case.

Good point, but presumably at that point you’re either creeping or rolling and that’s no different than an automatic or manual ICE vehicle.

 

[Need]

Good point, but presumably at that point you’re either creeping or rolling and that’s no different than an automatic or manual ICE vehicle.

There is a difference auto ICE and Tesla. Auto Ice car you kept your foot on the brake petal, so every time you slow, it is because you press the brake and brake light comes on. Telsa (unless you have creep enabled), you kept your foot on the accelerate petal. On slow traffic when you partially let go of the accelerate petal, the car will slow but brake light may not come on.

 

[r0xx0r]

Even with creep on and regen to low, the creeping speed doesn’t fast as an auto ICE. In stop & go, Everytime I hit the acceleration pedal, after that I just left my model X slow down by itself, even the car in front of me slighly hit their brake. I checked my dashboard many times. No lights!

After I realized many people hit their brake hard behind me. Now I have to push my brake to let people behind me having enough time to react.

 

[DCGOO]

The brake lights are also on during "hill hold," the little H in a circle (which is always active)

 

[skylla]

Distracted drivers.... This happened to my X a month ago.. At least got out without a scratch.

 

[Dr Doom]

Distracted drivers.... This happened to my X a month ago.. At least got out without a scratch.

damn that is terrible collision. poor MX.

 

[MDR SEA]

Probably not germane here but worth mentioning -
When approaching slow/stop traffic, AP1 seems to wait until the last (comfortable) moment to slow down.
After a few near misses, I now take control in these situations.
Other than that, Tesla AP is the "*sugar*"!
Still the best cars I've ever driven or owned!

MDR

 

[MDR SEA]

Distracted drivers.... This happened to my X a month ago.. At least got out without a scratch.

Holy s#!t!
Any guess as to how fast your new "friend' was going at time of impact?

 

[S4WRXTTCS]

Probably not germane here but worth mentioning -
When approaching slow/stop traffic, AP1 seems to wait until the last (comfortable) moment to slow down.
After a few near misses, I now take control in these situations.
Other than that, Tesla AP is the "*sugar*"!
Still the best cars I've ever driven or owned!

MDR

As long as AP1 is tracking the car in front of me it seems to slow down just fine. I do have a tendency to change the setting to 5 on stop and go versus my normal setting of 3. I like having a small buffer in case it doesn't act as I expect.

I wouldn't expect there to be differences in how it handles stop and go traffic.

Now this could be that I use TACC, and not AP for the most part. But, my understanding is this behavior is the same whether its TACC or TACC+lane-steering.

 

[MDR SEA]

As long as AP1 is tracking the car in front of me it seems to slow down just fine. I do have a tendency to change the setting to 5 on stop and go versus my normal setting of 3. I like having a small buffer in case it doesn't act as I expect.

I wouldn't expect there to be differences in how it handles stop and go traffic.

Now this could be that I use TACC, and not AP for the most part. But, my understanding is this behavior is the same whether its TACC or TACC+lane-steering.

What is TACC?

Not my experience with AP.
Had too many close calls to let AP take this one.
Though, of my 44K miles in my 85D, I'm easily 40K miles AP driving.

Still loving it!

 

[arubinst]

TACC = Traffic Aware Cruise Control

 

[MDR SEA]

Thanks.
I'm assuming that it's already active on my AP?

 

[r0xx0r]

Thanks.
I'm assuming that it's already active on my AP?

Non-AP Cruise Control will not slow down if the car in front of you reduces their speed. TACC will do.

 

[BlueBird]

My wife was following my X100 yesterday and without knowing about this thread, the first thing she complained on arrival was how difficult it was to follow my car as she could not trust my stop lights when driving in a stop & go traffic situation. I am typically using the regen to get the car to almost stopped and will sometimes keep enough acceleration pedal to maintain the car still until the traffic starts moving. In this situation, the car will mostly slow down and stop without any stop light. As somebody mentioned in the tread, it is human nature to pay additional attention to the car in front when the stop lights are activated. For security, Tesla should add an option to always turn on the stop lights when slowing using regen or at the minimum reduce the threshold speed that will trigger the stop lights.

 

[DCGOO]

My wife was following my X100 yesterday and without knowing about this thread, the first thing she complained on arrival was how difficult it was to follow my car as she could not trust my stop lights when driving in a stop & go traffic situation. I am typically using the regen to get the car to almost stopped and will sometimes keep enough acceleration pedal to maintain the car still until the traffic starts moving. In this situation, the car will mostly slow down and stop without any stop light. As somebody mentioned in the tread, it is human nature to pay additional attention to the car in front when the stop lights are activated. For security, Tesla should add an option to always turn on the stop lights when slowing using regen or at the minimum reduce the threshold speed that will trigger the stop lights.

All Teslas do exactly that. Always have AFAIK. If she needs to follow the lights, she is way too close.

 

[BlueBird]

All Teslas do exactly that. Always have AFAIK. If she needs to follow the lights, she is way too close.

Yes, but it does not mean it is the correct behavior. I do see here points in heavy “Stop and Go” traffic as our brain was trained to react to the car’s stop light in from of us as a go/no-go trigger. It will take time to change this behavior with the effect of having a higher probability of being rear ended. For our safety, I believe it would be better to have more rear stop lights then less or at the minimum to let us make this choice (like creeping). It would be interesting to know how many members had a rear-ended experience or had a close call.

 

[r0xx0r]

All Teslas do exactly that. Always have AFAIK. If she needs to follow the lights, she is way too close.

If the regen is low, it will not light up.

Eg, in stop & go traffic, ICE car travels at 15mph then they need to slow down to 5mph, they have to hit brake. For Tesla low regen, you just need to remove your foot from pedal. The car will reduce to 4mph in about 7-8 seconds without brake light.