Accident for unable to brake efficiently: Tesla's or my fault? [early 2020]

[patrick40363]

Hey all, I've got into a small accident couple months ago and hope we can discuss about this.

Dash cam recording goes first:

(I only blurred the license plate for privacy concerns. Nothing else edited, for example speed, resolution, color, etc)

This rear end accident happened last year, and luckily nobody was hurt. My Tesla insurance covered this, and I told them the brake was not working as intended right after the accident. I also called Tesla roadside assistance & service center to report this malfunction, and they promised I would get an investigation result within 8 weeks. Not surprisingly that didn't happen. So I'm still wondering who is at fault in this accident, because it seems obvious to me that the brake wasn't right. Or maybe I could be wrong and need to be more careful in similar situations.

Here're some key conclusions:

1. The road was wet but not raining when it happened, actually it showered in the morning and stopped about half an hour ago. Temperature was around 50°F - 70°F (10°C - 20°C), speed limit is 35mph.
2. My Model 3 LR AWD was very new with 2000 miles on it. It has the original 18'' aero wheels & tires. Manual driving all the time, no autopilot involved.
3. I started to brake right after I see the red light & front car slowing down, with regen first and then immediately pushed brake pedal hard. I pushed as hard as I could and it still hit the front car.
4. The wheel was making deep clicking sound, indicating ABS triggered, but car just won't slow down and tire is making abrasive sound.
5. No collision warning, no auto braking or any other safety features triggered (I enabled all safety features).
6. Brake & regen still working after the accident. Have't tried braking hard though as I don't trust it any more.

Welcome to share your opinions. Thanks in advance!

Driving to fast. Your fault.

 

[buttnutt]

I noticed that i have to press on the brake pedal a lot harder when I want to slow down faster. Or maybe it just feels that way since I almost never use the brake. Looks like it was OP's fault to me. I would hate to see your braking in an emergency situation. You won't stand a chance.

 

[Runt8]

Over the last few years, I've come to the conclusion that a disproportionate amount of the entire driving community do not know *anything* about cars or driving, so very basic things that I thought everyone was taught come up in topics with alarming frequency.

Fixed that for you

 

[Uncle Paul]

Looks like OP initially just used regeneration braking to slow the car. By the time he realized that he needed to brake more agressively it was too late.

 

[Tam]

so AEB doesn't protect you from yourself.. I wonder if AP would have avoided this accident?

I would say yes for AP IF you set the following distance conservatively at 7 and not lower than that due to the slippery surface.

According to the owner's manual, AEB does not avoid collisions. It only reduces the speed with the goal of lessening the force of a collision, and not preventing a collision.

 

[Dangerous Fish]

Here's a good illustration of how the right tyres for the conditions can prevent this sort of thing from happening.

 

[GoodManFrank]

Here's a good illustration of how the right tyres for the conditions can prevent this sort of thing from happening.

Also found this Comparison of best Model 3 compatible tires (18", 19", 20"), sourced from Tirerack.com ratings : teslamotors
Seems like OEM tire sucks...

 

[Dangerous Fish]

Also found this Comparison of best Model 3 compatible tires (18", 19", 20"), sourced from Tirerack.com ratings : teslamotors
Seems like OEM tire sucks...

All tyres are a compromise. The Michelins are not bad tyres, but they can't be expected to work really well in all conditions and temperatures AND have a low wear rate AND give you maximum range, so you have two choices:

1. Replace the MXM4 tyres with a better summer tyre or all-seasons or run separate summer and winter sets.
2. Drive to the conditions and within the operating range of the MXM4s

There are worse tyres than the MXM4 out there on the roads with people driving around on them and not crashing, so it can be done.

 

[GoodManFrank]

All tyres are a compromise. The Michelins are not bad tyres, but they can't be expected to work really well in all conditions and temperatures AND have a low wear rate AND give you maximum range, so you have two choices:

1. Replace the MXM4 tyres with a better summer tyre or all-seasons or run separate summer and winter sets.
2. Drive to the conditions and within the operating range of the MXM4s

There are worse tyres than the MXM4 out there on the roads with people driving around on them and not crashing, so it can be done.

Yep and getting better tire gives more control in emergencies. I'll take both choices

 

[smatthew]

That's just not true. The brakes are not fully bedded prior to delivery, but that is largely irrelevant in this case.
What is this preventative maintenance you refer to and where is it documented?

"Tesla has confirmed to Roadshow that its brake-and-roll testing and on-track testing procedures are identical. Both tests begin by burnishing (or bedding-in) the brakes by accelerating to 60 miles per hour and then decelerating down to five mph. This is done three times in relatively quick succession and is fairly standard practice across the industry."
from Tesla changed its testing regimen for the Model 3, and that's OK - Roadshow

 

[Dangerous Fish]

"Tesla has confirmed to Roadshow that its brake-and-roll testing and on-track testing procedures are identical. Both tests begin by burnishing (or bedding-in) the brakes by accelerating to 60 miles per hour and then decelerating down to five mph. This is done three times in relatively quick succession and is fairly standard practice across the industry."
from Tesla changed its testing regimen for the Model 3, and that's OK - Roadshow

You didn't read the article.
"While every Model 3 currently being produced gets driven on a track, Tesla doesn't expect that policy to continue either. Once the assembly process becomes a known quantity, with inefficiencies and errors ironed out, the average quality of the vehicles will go up, meaning there will be less likely to be wrong with any vehicle that rolls off the line. At that point, Tesla will change over to the same spot checking policy that it uses on Model S and Model X, both of which are by now well established in terms of manufacturing."

It's not happening now, at least not to UK cars I can assure you.

Where's the PM information?

 

[Candleflame]

This is why I drive like my friction brakes don’t exist 99% of the time, but then again, I hate energy waste when it doesn’t benefit me in time.

With the pre January 2020 regen there wasn't even a real purpose for the brake outside of emergencies. The regen was just ultrastrong. Now it takes a bit of planning.

 

[Msjulie]

Wet road + possibly also wet brakes (rotors) - Treat those conditions with a lot of respect

 

[Msjulie]

Tesla vehicles monitor the brake usage and will scrub the brakes to clean the rotors if needed.

Can you provide a link that explains this and how it works (conditions)?

I have never seen this to occur and I generally do this myself when braking in the rain. Sounds interesting but also potentially disarming to a user to have brakes activate, even if ever so slightly.

 

[chinnam3]

I’m going to blame the tires. Tesla’s fault for using crappy tires and your fault for not realizing how it handles in some wet situations.

I have the same config but got mine Sept 2018. I was driving one day after it had rained and had trouble with the tires losing traction on regen on an exit ramp. I had a few other times where the tires had wet traction issues slowing down and accelerating. What was your tire PSI set to? I kept mine at 45 and I’m sure that did not help things.
My solution was to buy PS4S summer and Nokian winter tires. The Nokian tires are not star performers on warmer wet roads but not as bad as the factory ones. PS4S tires are like the car is glued to the road dry or wet.

I still have my factory tires with 3,000 miles on them hanging on a rack in my garage. I guess I should try to sell them before they dry rot.

I completely agree. The OEM Michelin 18in tires are pathetic on wet roads. Slight acceleration on wet roads, these tires will spin, and I am very cautious with these tires when road is wet and increase my distance considerably. I do not remember any tires in recent memory being this bad when roads are wet.

 

[sperkin]

You were driving faster than the car on the right and on the left. You also sped up when the car on the left wanted to change lanes. You sped up when everyone else was going into a stop so you didn't have enough time or distance to stop on wet road.

This looks like your fault. The car slipped at the last second on the water. You can see the road was reflective so the water didn't run off. It was just sitting there on the surface.

You should send us a picture of your tires. I am wonder what the tread depth was.

 

[lotusland]

... the lead car driver should have some situational awareness and notice the car in the rear view mirror coming in hot. There does not appear to be any pedestrians near the crosswalk and plenty of room to creep forward to allow more space for the Tesla driver to stop without collision.
Defensive driving is the best kind of driving.

Not quite the same as being on a bike. From a legal perspective it is much better to be "not moving" at the time of an accident. If the front car had pulled ahead it is possible the blame would have shifted, especially if he had then been pushed into anything/anyone else. Of course if injury is going to result -- like if you were on a bike or if the speed was very high -- than I would still pull up.

This accident is totally the fault of the OP and it is insane to waste any of Tesla's time "investigating" this. I suggest OP retract his request. There is nothing wrong with the brakes on the Model 3.

 

[TLLMRRJ]

None of us were there, except for you, so blaming you or the car is not a smart thing to do.

If it hasn't already been mentioned (didn't read all 5 pages, sorry), the right course of action is to find some wet slippery roads that don't have any hazards and do some of your own testing of the brakes to either confirm they are not working correctly, or to regain confidence in them and have a better feel for your stopping power in those conditions.

 

[justsomeguy]

Can you provide a link that explains this and how it works (conditions)?

I have never seen this to occur and I generally do this myself when braking in the rain. Sounds interesting but also potentially disarming to a user to have brakes activate, even if ever so slightly.

I can't speak to whether or not the Model 3 does this, but there are plenty of cars that do it, just google "brake drying"

 

[Msjulie]

I can't speak to whether or not the Model 3 does this, but there are plenty of cars that do it, just google "brake drying"

Thanks - some BMW's supposedly do it with rain sensors but I gotta say my car's behavior suggests to me Tesla is not doing this in the Model 3, at least now. I prefer that actually but then again I'm OCD about stuff like this.