Forward Collision Warning Just Saved My Bacon

[SomeJoe7777]

I was driving southbound on Highway 6 in west Houston, looking for a restaurant that I had never been to. While looking to the sides of the road for the building and it's address, a car slowed to a stop in front of me that I did not see, and I nearly rear-ended him. In fact, I'm nearly positive I would have rear-ended him without the Tesla's Forward Collision Warning alert, which alerted me to brake.

Note that this was NOT Automatic Emergency Braking (a feature that will brake and slow the car for you to mitigate a rear-end collision). I performed the braking maneuver myself, the car did not.

My reaction time from the first loud beep of the Forward Collision Warning alert to stepping on the brake was 0.766 seconds. My dashcam recorded a maximum deceleration G-force during the braking maneuver of 0.9 G.

Note that my dashcam time is off, it's on GMT, I'm in US Central. Actual time of day is 19:31.

This is the G-Force graph from the dashcam. The Forward-Back (FB) line in purple shows the braking maneuver.

I deleted my colorful language in the video, but I think you can deduce what was uttered.

 

[S4WRXTTCS]

It doesn't count if you didn't have to change your underwear.

Dashcams are pretty sweet though.

 

[larmor]

Do you keep bacon in the Frunk?

 

[SomeJoe7777]

Do you keep bacon in the Frunk?

No. If I did, I wouldn't be able to drive very far, I would constantly have to stop and make a sandwich.

 

[Boatguy]

Interesting because just yesterday the AEB triggered momentarily while I was driving down a street with no obstructions at all. I was just zipping along at about 40mph and suddenly the beeps, brakes momentarily, and then resumes as though nothing happened. I was WTF, there is nothing here. Sorry, no dashcam.

 

[SomeJoe7777]

Interesting because just yesterday the AEB triggered momentarily while I was driving down a street with no obstructions at all. I was just zipping along at about 40mph and suddenly the beeps, brakes momentarily, and then resumes as though nothing happened. I was WTF, there is nothing here. Sorry, no dashcam.

Did you have TACC engaged? I've seen it before numerous times that when TACC is engaged, every once in a while the radar will get an anomalous reflection from a sign, concrete jersey barrier/wall, crash-mitigation barrels, etc. and cause the car to think that another vehicle is in front of you when it isn't. You'll hear the forward collision warning (FCW), see a red car on the display, and also feel TACC slow the car. However, this isn't AEB, this is just TACC reacting to the ghost car.

 

[Boatguy]

Did you have TACC engaged? I've seen it before numerous times that when TACC is engaged, every once in a while the radar will get an anomalous reflection from a sign, concrete jersey barrier/wall, crash-mitigation barrels, etc. and cause the car to think that another vehicle is in front of you when it isn't. You'll hear the forward collision warning (FCW), see a red car on the display, and also feel TACC slow the car. However, this isn't AEB, this is just TACC reacting to the ghost car.

Yes, TACC was engaged and played out as you describe. You're quite possibly correct that it was just TACC cutting out rather than AEB cutting in; sudden deceleration, though not a full stop, in either case.

 

[Max*]

AEB displayed a message "Emergency Braking in Progress" on your IC, and it stays for maybe 5-7 seconds after it's done.

AEB will throw you forward, it's going to be a hard braking. TACC will do the beep-beep-beep moderate braking, then back to normal speed.

 

[CarlitoDoc]

Interesting....so the car won't stop on its own? How about with AP 2.0??

 

[Thesaint]

Good Stuff.... Im glad it worked well.

 

[Dbitter1]

What dashcam do you have... with an accelerometer? Thats's awesome.

 

[SomeJoe7777]

What dashcam do you have... with an accelerometer? Thats's awesome.

This is the BlackVue DR650GW-2CH. It's 1920x1080/30fps front camera, 1280x720/30fps rear camera, both record to a single SD card. Accelerometer is viewable from the BlackVue viewer app, along with GPS position and speed.

 

[⚡️ELECTROMAN⚡️]

Definitely think the dash cam is essential hardware for the Tesla. My Lexus, not so much.

 

[theslimshadyist]

Interesting....so the car won't stop on its own? How about with AP 2.0??

I too am curious as to when the car will stop or brake on it's own vs when it won't and the emergency warning to brake goes off. One would think there would be more consistency, perhaps in the future? I dunno.... impatiently waiting on my car to enter production so I don't have first hand experience but I often get confused with this subject.