GeoX750Li

My adaptive cruise has 3 settings for the follow distance, but the shortest distance still seems about 2 seconds long.

Is there a setting/way to reduce that ?

Jack88

Not that I know of, nor do I recommend it. That's the minimum distance recommended by the highway safety board. Although the A8 reacts faster than you, it also doesn't look past the cars in front of you, so it doesn't want to follow too close if the guy in front of you rear ends someone. Given people tend to rely on these systems, I'd say even 2 seconds is too close for people using the tool to slack off. It also allows the car to not require braking quite as hard during a panic stop, giving people behind you more opportunity to not rear end you. The two second gap only seems like a lot when everything is going right and the irritating odd man uses this to cut in front of you.

HouTexAudi

There is a setting in the MMI to change the ACC to dynamic mode and I think this helps a little with the minimum distance. Still, when I use it to "follow" the car in front of me in the left lane on the freeway there is still too much distance to keep other cars from going around me on the right and cutting in front of me. I know the rule of thumb is one car length for every 10 MPH but if you do that around here you will constantly be cut in front of.

snagitseven

If the D4 works like the C7, the ACC setting in the MMI affects the acceleration response time to the changing distance of a followed vehicle but not the distance itself.

GeoX750Li

I get the system needs some margin of safety, especially since it must account for all kinds of road conditions. 2 seconds, however, really accounts for a human driver who is generally slower to recognize a braking event and then physically move his foot over from the gas pedal to the brake.

The ACC system should be quicker and not need the same margin of error as a human driver ?

The downside is I don't use ACC, lose the safety benefit altogether and end up following closer manually.

Its pretty eye-opening to realize that nobody where I drive is actually following at 2 seconds. I am starting to be an older driver trying to learn to enjoy comfortable cruising.

Jack88

I addressed concern here -->

The 2 second margin doesn't just allow for reaction time, it's a buffer in case the A8 can not stop as fast as the car in front of it, whether that be due to a higher performing vehicle being in front of you or one who has had assistance stopping by way of having struck something.

The older I get, the less aggressive I get, despite driving faster and faster cars. Tailgating is dangerous and far too many people do it either to try to 'push' the driver in front of them out of the way or to make sure no one gets in front of them. I've found that being aggressive often saves seconds, not minutes, over the course of a commute, and despite having got there faster, I am more stressed. The more I learn to ignore people cutting in, plan ahead, and try to smooth out my driving, the happier I am when I get where I am going. In fact, I found I'm happiest in the second fastest lane. People tend not to cut in front of me as much, and I get where I am going more or less as quickly. I can be aggressive when I need to be, having done my share of Middle Eastern driving, I am comfortable being much more aggressive than most Americans if needed, but mostly I'm learning more and more to just float along at whatever the average speed is for traffic. Adaptive cruise is not for aggressive driving, it excels at just cruising along with everyone else not in the fast lane.

MP4.2+6.0

Variously:

1. The ACC has four positions on mine, rather than 3. I have mine pre-set to my preference. Don't recall if that was MMI or VCDS mod.

2. snagitseven was correct; the Dynamic or Individual Car settings only affect how aggressive ACC is in catching back up.

3. From trying mine today, one the closest setting and counting it off in my head, it was just under 2 seconds. Call it maybe 1.75. In real world, plenty close.

4. Yeah, stressed out drivers are going to be clowns at times and bully his/her way in, but fix isn't to ride guy in front or the counter crap move of intentionally closing gap. Seen lots of parked in the weeds/rocks/shoulder line ups of like 5 dented cars when any one makes a miscue and whamo next four domino's fall. Also see more than a few flipped SUV's these days that seem to start w/ nothing too dramatic--sudden swerve, texting crap thing where they wake up and cut wheel other way, a curb trip, lots of things. Or, dropped load or roof rack scenario and stuff goes flying. Seen all those. I have had a fair number of experiences where the need for a clear way out or stop hard is not even the vehicle in front of me, and leaving only a second type gap would likely have been ugly. Also definitely have had the guy in front of me swerve for potholes, animals, crap in road, etc. Do all those myself too. Too bad for guy behind if riding bumper when the traffic is heavy already. Maybe all time best was just a week ago. The usual line of 5 carcasses on right shoulder of four lane interstate ready to be hauled off for driving too fast in obvious heavy rain. Car in front of me slows then swerves suddenly, out of my lane. Typical SUV so couldn't see clearly in front of him before hand., other than I sensed the lane was oddly "open." At time figured vehicle in front had slowed some for the rubbernecking along w/ lots in the lanes closer to the side of road show. Guess what, right there in road in my #2 lane was a complete wheel AND half shaft still bolted to it (or whole hub assembly) from one of the carcasses that somehow still got to side of freeway. Basically dull metal black on gray wet concrete in rain and bad overcast. Had I been like a second or second and a half off that guy's rear end..in the rain...might never have had the reaction time to catch it, especially with the accident rubbernecking right there, side of road accident show, etc. That would have been ugly, and a prime example of the way unexpected you can't train for beyond general prudence, safe following and trying to keeping in mind situationally ways out and full on straight stop alternatives.