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Concerned about rear collision when car slows on its own

White Knight

Member
Sep 18, 2019
42
0
Honolulu, HI
I bet tesla get hit from the back a lot compared to the other cars. On auto pilot, sometimes the car slow down drastically that i press the gas so i don't get hit in the back. Especially in traffic where sometimes we go fast and suddenly
we slow down. Or if we don't lift off the gas pedal slowly the car will slow down faster without pressing the brake pedal. It can be a problem if we don't warn the car behind because there is no brake lights won't get activated. That how i drive defensively watching those brake lights ahead.
 

ecarfan

Well-Known Member
Sep 21, 2013
19,205
13,856
West Vancouver, British Columbia
I bet tesla get hit from the back a lot compared to the other cars.
You mean you “speculate” that is the case, because you have no real data to support your statement.
On auto pilot, sometimes the car slow down drastically that i press the gas so i don't get hit in the back.
If the car slows drastically it is because traffic ahead is slowing drastically. And your brake lights will come on by themselves.

It can be a problem if we don't warn the car behind because there is no brake lights won't get activated.
Incorrect. The brake lights are activated automatically when the car slows significantly on its own.
 

tvad

Member
Jun 30, 2019
979
972
California
@White Knight, I have the same concern about the possibility of being rear ended due to the Tesla's abrupt braking in moderate to heavy traffic...particularly in situations where a car suddenly changes lanes into the gap in front of the Model 3. This always causes the Tesla to brake/slow much more abruptly than we do ourselves when driving with full control of the car.

This concern continues even though the brake lights come on in those situations. We always follow farther behind the car ahead to allow us space to advance forward if we see the car behind approaching too quickly.

I am writing specifically about abrupt braking while on Autopilot.

OP, if you haven't already, you can switch regen braking from Standard too Low. Low will slow the car in a manner similar to an ICE car, and it will be less abrupt.
 
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alsetym

Member
Apr 28, 2018
258
278
hamilton
How about being less worried about rear-ending the car in front of you because you screw up or aren't paying attention. If the guy behind you hits you, it's because he is not paying attention or has insufficient following distance. If they are tailgating you, get out the lane. Defensive driving FTW!
 

Joshan

Member
Jan 8, 2019
517
839
Chicago
I think you're not taking into account drivers not paying attention to brake lights because they're texting, applying make-up, loading vape pens, etc while driving. Happens every day where we live.

Which has zero to do with a Tesla and affects every car on the road. What exactly was your point? If the driver behind you is not paying attention, what car has systems to stop you from getting rear ended when driving forward?
 

Cogarch

Member
Apr 27, 2019
234
171
London
I think the hostile tone of many of these posts is unwarranted. When on Autopilot I have experienced sudden emergency braking several times while in the fast lane caused by AP mistaking a gantry or other non-issue as a hazard. Thankfully I have not yet had anyone crash into me but it is a reasonable thing to fear.
 

tvad

Member
Jun 30, 2019
979
972
California
Which has zero to do with a Tesla and affects every car on the road. What exactly was your point? If the driver behind you is not paying attention, what car has systems to stop you from getting rear ended when driving forward?
My point is that a car that slows/brakes abruptly is more likely to get rear ended by a driver following too closely and/or not paying attention.

Our Tesla slows much more abruptly while on Autopilot in situations where cars "dive" into the gap in front of us.

Unfortunately, tailgating is common in So California...and at typical 70+ mph freeway speeds, it's safer to maintain a smoother pace than Autopilot accomplishes in the situation I described above. If possible, it's smart to change lanes away from tailgaters (as was mentioned earlier), but that's not always an option when traffic is heavy.

For this reason, we almost always prefer to have full control of the Model 3 on So California freeways.

Hope that helps.

BTW @Joshan...tailgaters abound in Chicagoland! It's as crazy there as in So California...sometimes I think even moreso.
 

camalaio

Active Member
May 28, 2019
1,483
2,087
Vernon, BC, Canada
I think the hostile tone of many of these posts is unwarranted. When on Autopilot I have experienced sudden emergency braking several times while in the fast lane caused by AP mistaking a gantry or other non-issue as a hazard. Thankfully I have not yet had anyone crash into me but it is a reasonable thing to fear.

100% agree, though I do think people are also rightly pointing out that sufficient regenerative braking does indeed engage the brake lights though. In that respect less hostility would be appreciated towards someone who is new to regenerative braking.
 
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Darthbenji

Active Member
Mar 27, 2018
1,003
594
Ontario
I happen to agree with the OPs concern. I too have looked in my rear view more than once to see if autopilot’s abrupt braking was going to get me rear ended. The car brakes earlier and harder than a human would. Not all the time but sometimes. In those moments it is a risk to be rear ended. Brake lights are a red herring in this discussion. They exist on all cars and illuminate when heavy braking occurs. That they do, does not preclude a rear end collision. Rear enders are the most common type of collision there is on the roads. The reality is many many drivers do not follow at a safe speed and distance making brake lights of little help when a sudden slow or stop is necessary.

If you don’t find autopilots braking too aggressive sometimes, maybe that’s just the way you drive when you’re in charge and it feels normal to you. A car or driver suddenly braking heavily in traffic when it’s not needed is asking for a hit from behind.
 

KenC

Active Member
Sep 4, 2018
3,482
3,166
Maine
I vaguely recall a similar thread came up on the Chevy Volt forums, and that someone pointed out that the brake lights are triggered by a deceleration rate of -1G. And as others have noted, you can see the lights come on in the visualization screen.
 

C141medic

Active Member
Apr 9, 2016
1,714
1,496
New Jersey
I think you're not taking into account drivers not paying attention to brake lights because they're texting, applying make-up, loading vape pens, etc while driving. Happens every day where we live.
Agree there are a lot of drivers not paying attention. Unfortunately we can’t control against this no matter if we’re driving a Tesla or another vehicle if the drivers behind us do not maintain proper following distance.
 

camalaio

Active Member
May 28, 2019
1,483
2,087
Vernon, BC, Canada
I vaguely recall a similar thread came up on the Chevy Volt forums, and that someone pointed out that the brake lights are triggered by a deceleration rate of -1G. And as others have noted, you can see the lights come on in the visualization screen.

Well that can't be right. You'd have to run into something to pull 1G :D but point taken
 

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