Adaptive Cruise - Car buffer/car length feature no longer works

[markinsf]

I've owned my X for about 3 months. I use AP (autosteer and cruise) very often.

Lately I've noticed that the car buffer/follow distance setting has zero effect.

Before it was very noticeable to change the car length follow feature for AP - the car would quickly speed up and slow down when changing this setting to adapt to the car length specified.

Now there is no effect. I can set the follow distance from one car to seven and it always seems to be about 3 car lengths behind the car ahead of me. There is no discernible acceleration or deceleration nor adjustment of the distance from the car in front of me.

Has anyone else experienced this? I've already tried a soft reboot. I'm on 2019.12.1.2

Thanks.

 

[scottf200]

... There is no discernible acceleration or deceleration nor adjustment of the distance from the car in front of me....

At what diff speed have you tried? Slower speeds there is less of a diff.

 

[markinsf]

At what diff speed have you tried? Slower speeds there is less of a diff.

Doesn't matter if I'm going 80mph or in stop and go city traffic.

Before it was very noticeable when I changed the car lengths - the car would speed up or slow down to change the distance (usually would change at highway speeds). Now... nothing.

 

[jboy210]

Doesn't matter if I'm going 80mph or in stop and go city traffic.

Before it was very noticeable when I changed the car lengths - the car would speed up or slow down to change the distance (usually would change at highway speeds). Now... nothing.

A few thoughts.
One is to take it in have them check it.
Two. I have read that wrapping the car can mess things up.
Three. The latest software changes have made the slowing because a car cuts in front much more subtle and less jarring. More like backing off the throttle in a gas car and less like dropping an anchor.

 

[NoSoup4U!]

I am experiencing similar behavior. Especially in stop and go, there's no difference between 2 and 4. Car was built in dec 2018. Same software version.

 

[neroden]

Uh-oh. That's a pretty serious disaster of a bug. If the adaptive cruise follows closer than a driver wants it to, then it just has to be turned off.

 

[NoSoup4U!]

Uh-oh. That's a pretty serious disaster of a bug. If the adaptive cruise follows closer than a driver wants it to, then it just has to be turned off.

Oh the humanity!

 

[markinsf]

Hi All. Any others experiencing this issue? Or do you have any suggestions on how to resolve?

I just received yet another update and am now on 2019.16.2. Yet the problem persists.

I've recently been driving more in heavier traffic and, as the car seems to be "defaulting" to a 3 car length follow - regardless if I set the follow to 1 car or to 7. Then I will get a string of cars that will cut in front of me the entire commute home. It's a little frustrating.

Hate to take the car in to the service center for such a minor issue (and it is supposed to be "beta," right?) yet the problem is starting to become an annoyance.

Thanks for any input.

 

[P85_DA]

Yah I just noticed as well but I normally drive at “1” now my car is to far away on 16.2​

 

[jdw]

(When working correctly) the distance will vary depending upon the speed as the numbers refer to seconds, not car lengths. 1-2 is roughly 1 second behind the car you're following, so at 60 MPH there is a greater distance between cars than at 5 MPH. Each number is roughly ½ second.

This allows you to maintain the same "safety buffer" for reaction time at any speed.

If you think about it, 1 car length is too great a distance in stop and go and far too close at highway speed.

I do wish there was a shorter follow time for mid-speeds as leaving a distance that invites aggressive drivers to cut in front of you is more dangerous than a shorter follow distance. Bring on .5 ...

 

[markinsf]

(When working correctly) the distance will vary depending upon the speed as the numbers refer to seconds, not car lengths. 1-2 is roughly 1 second behind the car you're following, so at 60 MPH there is a greater distance between cars than at 5 MPH. Each number is roughly ½ second.

This allows you to maintain the same "safety buffer" for reaction time at any speed.

If you think about it, 1 car length is too great a distance in stop and go and far too close at highway speed.

I do wish there was a shorter follow time for mid-speeds as leaving a distance that invites aggressive drivers to cut in front of you is more dangerous than a shorter follow distance. Bring on .5 ...

Thanks. Yes, I agree with what you are saying. I would not want to be 1 car length behind someone while driving 80mph. On a city street with stop lights and puttering along at 15mph? I think 1-2 car lengths is acceptable.

I just drove into work and was testing it both on the highway at 65mph and on a city street at 20 mph. There is no difference whatsoever when I change the car length.

In fact, when I was on the highway I set the car length to 7. A car in front of me changed lanes and my car sped up to within 3-4 car lengths of the car ahead of me essentially overruling the setting of 7.

The setting is now completely ineffectual. Before it would be a noticeable difference and, in fact, in the past I even was a bit startled when I forgot I had set it to 2 and got on the highway and discovered I was following the car ahead (while on AP) at an unsafe distance.

The setting simply no longer works.