TACC On Mountain Roads

[Wingsy]

Hello people. Just ordered my Model 3+ with FSD yesterday and this is my first question. And certainly not my last.

My previous most favorite car was my Dodge Charger R/T with adaptive cruise. It's an outstanding ACC and much better than 3 other brands I recently tested when out shopping with my wife for her new car. (Got a Lincoln MKC) Now I want to know about the M3's cruise when on a very curvy road. The Charger's ACC can hang in there following the car ahead on curves so tight all I can see is the corner of the car ahead and it doesn't lose lock. Acts like it's being towed.

It would seem to me that the M3 would be better or certainly at least as good. After all, it knows the path ahead and radar/cameras can tell if the thing in front of me, going the same speed, is in my lane or not. So based on your experience on very curvy roads, you think I'll be happy with it?

 

[Wingsy]

I should mention this... one slight drawback to the Charger's excellent tracking ability is that when a car ahead changes lanes and slows down, so do I. Some. As soon as it realizes Im not turning with it, it drops the lock and I resume. Sometimes it's not noticeable and occasionally it is. If it knew there the lane was it could do much better. All it has is radar.

 

[Dre78]

The Charger's ACC can hang in there following the car ahead on curves so tight all I can see is the corner of the car ahead and it doesn't lose lock. Acts like it's being towed.

When I use TACC, it's responsive to road ahead as well as tracking car. When approaching a bend, TACC will slow down regardless of whether a car is ahead or not. At times I've had to apply throttle to maintain speed.

Additionally, it freaks out with crossing traffic. If a car turns left from oncoming traffic in the distance, TACC will tap the brakes abruptly (and a bit delayed).

There are a couple posts on the board which may or may not apply, indicating on curved roads if a car drifts from your lane but doesn't fully leave, TACC may maintain speed (or accelerate) you into that car. The exact circumstances vary (NoAP, exit ramp, etc.).

TL;DR, I don't think Model 3 will be the same experience as Dodge, and fear you will be disappointed.

Good luck! Keep us updated!

Edit to Add: in regards to cars leaving your lane, yes, in my experience TACC will accelerate after the car departs your lane, even through a curve, assuming the car departs your lane before slowing.

 

[Wingsy]

Thanks Dre. I'll be sure to come back and relate my experience after driving to Cherokee NC, once I get it.

 

[Wingsy]

Well I haven't been to Cherokee yet but did go to a state park located in the foothills of NC. I had about 5 miles of winding roads, 2.5 up there and 2.5 back. While going up the mountain I had no one in front so couldn't test that. Going down I followed someone and my results were good and bad. The Good: it did not appear to ever lose radar/visual lock on the car ahead. I had my speed set to 50mph and we were traveling at around 20-40, so if it ever did lose lock (and the road was straight enough) I would feel acceleration into the car ahead. Never did that. The Bad: It seemed that no matter what I set the following distance to, it ignored that and followed at a setting that appeared to be "1". Pretty darn close. Not close enough to prompt driving directions from my passenger but my preference would be to back off a bit more.

I think I'll be happy with its ability to follow on winding roads. Now if they would just work on preventing TACC from slamming on the brakes for no apparent reason (that's for another thread).

 

[bwilson4web]

I think I'll be happy with its ability to follow on winding roads. Now if they would just work on preventing TACC from slamming on the brakes for no apparent reason (that's for another thread).

You might consider using the built-in dash cam and recording those incidents. I've seen a few unexpected, light braking events but nothing of note. Our 'magic eye' based, BMW i3-REx tends to have more problems with shadows across the road.

Bob Wilson

 

[SammichLover]

Additionally, it freaks out with crossing traffic.

I've noticed this has improved somewhat with 16.2. Its reactions, both positive and non-reactions, are a lot more inline with what I'd personally do.

As for @Wingsy , it is really good but concrete side barriers still do overly concern it at times. I manual override for that occasionally, if it looks like something it won't like.

I suspect it is concerned they represent merging traffic or something, not sure, but sometimes on curves where there are concrete retaining walls the TACC will slow unnecessarily. Particularly when approaching a crest. Other than that it's very solid, and correctly reads 2 vehicles deep ahead too, incase the person you're following is too close to the vehicle in front of it or the lead vehicle is slowing before the one directly in front of you.

There was someone on here that reported issues specifically with sharp shadows on the road, which you'll see more of in mountains, too.