A4Driver

Has anybody actually had Pre sense city kick in and prevent a collision? I'm here to say that it doesn't work on my car.

I'm embarrassed to admit it, but I almost wrecked my car about a half a block after driving out of my dealer's lot for the very first time. I was so overwhelmed by my car's electronics, that I completely missed a Stop sign and proceeded to drive right through an intersection. At some point, my peripheral vision picked up a Honda Accord quickly approaching the intersection from my left in the cross street. As he reached the center of the intersection, I was about one car-length from hitting him broadside when I slammed on my brakes. Luckily, the roads were dry and I stopped in time, but I can't say the same thing about my heart, which was pounding out of my chest.

According to Audi: "All of the versions of the new models include the safety system Audi pre sense city as standard equipment. At speeds of up to 85 km/h (52.8 mph), the system scans the road for other vehicles and pedestrians using a windshield-mounted front camera with a range of up to 100 meters (328.1 ft). If there is the threat of a collision, the driver receives a series of warnings, and if necessary the car starts to apply the brakes fully. At speeds up to 40 km/h (24.9 ft), it can fully prevent accidents within the system limits. At higher speeds up to 85 km/h (52.8 mph), warnings and brake intervention can reduce the impact velocity."

Fast forward to a couple of weeks ago. I was driving down a local street when a man suddenly and without warning stepped off a curb and crossed the street in front of me. I was driving about 30-35 mph and my car gave me no warnings and did not apply the brakes. I was forced to brake suddenly to avoid hitting the guy. Btw, he was not in a crosswalk; he was crossing in the middle of the block.

But Audi says: "Pedestrians can be detected while the vehicle is traveling at up to around 65 km/h or 85 km/h (40.4 mph or 52.8 mph), depending on the car model ... If a collision is imminent, the system warns the driver with visual, acoustic and haptic warnings based on a multistage warning concept. If necessary, the system provides braking assistance to reduce vehicle speed or initiates a full brake application to avoid the collision under certain circumstances ..."

Meanwhile, my Pre sense Rear seems to work properly. At least the visual warning part does. If a vehicle is approaching while I am backing up, red arrows appear on my MMI screen while in rear-view mode. Whether it would apply my brakes in time to avoid a collision is something I am not willing to test.
.
.
.

SYMAWD

The first time it did not work because it only picks up cars going the same direction as you. I can't say about the second situation as I did not witness it.

SCarGuy

Correct as to scenario #1

OP - first thing I'd check is to go through your owners manual and make sure Pre-Sense is properly configured within the MMI.

superswiss

The pedestrian situation should have been handled as far as I'm concerned, so make sure pre sense is actually turned on, but pre sense city does not handle front cross traffic. Pre sense city only detects oncoming vehicles, not vehicles that cross in front of you, unless it's an oncoming vehicle turning into your lane (Turn assist). Audi does have a Crossing assist that works up to 6.2 mph, but that's not offered on the A4. The A4 only has rear cross traffic assist. Following is a good page that lists all the assist features with the handled scenarios.

2018 Audi A4 Driver assistance | Audi A4 | Audi library

Samuel Weir

Glad that the OP brought up this question about the effectiveness and operation of Pre-Sense City because I've been wondering about it myself since we bought our new 2018 Audi a little over a month ago. During the test drive of another A4, I saw the Pre-Sense City warning pop up on the screen in front of me once in moderately heavy traffic, but during the time we have owned our car (a little over a month now) I haven't seen any Pre-Sense City warning even when I deliberately tried to trigger it once by braking a fraction of a second later than I normally would. Is the Pre-Sense City system awake? Is it actually scanning the road in front of me? Absolutely no idea. I'm hoping that it works if I should ever need it, but I have no idea whether it is awake or asleep or non-functional. Would be nice to have a diagnostic mode in which one could see some indication of the internal "brain waves" of the Pre-Sense City system on the MMI display as one is driving along or stopping behind a car at a stop light.

A4Driver

I would imagine that my Pre Sense is actually turned on, because I have gotten several false alerts from it. In each case, I was far from being in danger of a collision, and in one case there were no cars within 100 yards from me.
.
.
.

Versprechen

It definitely works in the programmed scenarios -- saved me from rear ending someone around a blind curve with stopped cars that the sensors saw and reacted to before I had a chance.

KevinB656

It saved me from hitting a deer at night. The car was braking before I even saw the thing. It was ironic since a deer strike totaled my previous car and resulted in me buying the Audi to replace it.

jeffj2h

bob m

That happened to me a few times and the first time I actually got of my Allroad to see if I hit anything. Yep, jarring is the right word.