Why isn't it possible to set cruise control to follow speed limit?

[bhzmark]

It's the first part of his "Answer 2." That's just not correct. He wrote: "Answer 2: you CAN set the car's cruise control system to follow the speed limit." You can't.

If by "cruise control system" you mean the "actual car speed", then you are correct.

But by "cruise control system" I meant, simply, the part of the cruise control system that both indicates and will match the determined speed limit (and confidence level thereof) with the tick mark (solid or dashed) on the speedo. And which you can easily and quickly match with a simply binary driver input.

That part of the cruise control system matches the changing speed follows the speed limit. Automatically ... I dont have to anything at all. And whenever I want the cruise max speed to change to a new speed limit I ** don't have to dial it up or down** .. I simply pull the lever back and hold briefly the car max cruise matches the new speed limit.

I'm sure people were missing that functionality. It isn't obvious -- it also isn't totally automatic. But it doesn't require the driver to adjust the speed up or down a little or a lot -- it only requires the driver to input -- use the new set speed.

Sorry if makes your head explode. I find it to be very useful and as automatic as I wld want it to be given the inherent inaccuracies of the speed limit reading.

 

[ecarfan]

I think that -- finally -- you two are in agreement and this misunderstanding has primarily been because of semantic disagreements and not disagreement over how TACC really works.

I suggest you both let it end here. Just a suggestion...

 

[Andyw2100]

I think that -- finally -- you two are in agreement and this misunderstanding has primarily been because of semantic disagreements and not disagreement over how TACC really works.

I suggest you both let it end here. Just a suggestion...

I had already decided to do that.

bhzmark's last post "clarifying" things (and in particular the second paragraph) should have made everything that came before it even more clear to anyone following along, without me having to write another word.

 

[marchyman]

It's the first part of his "Answer 2." That's just not correct. He wrote: "Answer 2: you CAN set the car's cruise control system to follow the speed limit."

It is an ambiguous statement, not an incorrect statement. The phrase "to follow the speed limit" can be read as "change speeds to match speed limit changes". It can also be read as "change speed to match the current speed limit". I get in trouble for using phrases like that all the time -- just ask my wife As both of you agree the car does not "change speeds to match speed limit changes" (for good reason, IMHO) but can "change speed to match (what the car thinks is) the current speed limit" with driver input.

I had my car read access road speed limit signs. I'd be upset if all of a sudden the car, without input from me, decided to slow down to 35 in a 65 zone. I also wouldn't like the ticket I might get if the car sped up when reading the 65 MPH sign as 85 MPH. I've seen both of those mis-reads on my Model S.

 

[Andyw2100]

It is an ambiguous statement, not an incorrect statement. The phrase "to follow the speed limit" can be read as "change speeds to match speed limit changes". It can also be read as "change speed to match the current speed limit". I get in trouble for using phrases like that all the time -- just ask my wife .

And I get in trouble for not knowing when to quit, picking at nits, etc. --just ask my wife.

I respectfully disagree.

By using the word "follow" instead of, say, "match" or "equal", bhzmark is indicating a repetitive action, not a single action. That removes the ambiguity.

 

[CHG-ON]

OK, how about this:

Once engaged, holding the stalk toward you for a few seconds will set the cruise to the CURRENT perceived speed assist setting. However, it will not adjust automatically as the speed assist setting changes, due to changes in the speed limit.

No matter how you slice it, it is an unintuitive setup and unnecessarily confusing. Hence all the back and forth, and frustration, to find a logical and comprehensible way to explain it.

To me, this looks like an engineer implementation with the best of intent without enough user input to fully understand how the driver will understand how to use it quickly and intuitively. I think the latest 6.2 implementations of blind spot and nav routing with SCs suffer from the same thing. They need to increase the number of beta testers to get a broader set of reactions. There are so many variables with this stuff: everybody does things in their own way, road and traffic conditions change constantly. This stuff is complicated, so I expect a rocky road on some of these things. But I think that more testing in the real world with real people would go a long way to better roll outs.

I would much rather wait a bit longer for any software rollout if they would suss out all the issues and address them more fully so that we aren't all wondering WTF they are doing.

PS: Their documentation on all of this stuff is terribly bad. It leaves us all guessing every time they make a change. I don't want to guess, as it takes my attention away from driving, where it should be, as I try to make something work that was never explained properly.

I love the innovation. I just suggest they spend more time up front debugging.