My radar detector detects both radar and Audis!

No, it’s not my imagination.
Whenever my radar detector sounds an alert, I slow down a bit and start looking for the police car.
Sometimes when I am riding on the highway, the detector will sound continually for…miles at a time…even though there are no police cars in the immediate vicinity.
Then, a couple of months ago, I noticed that whenever I am in one of these situations where the radar detector just keeps sounding-off for miles at a time, there is a late-model Audi sedan fairly close to my car.

Rather than just assume that my observation was correct, a friend confirmed it for me–even though I had not mentioned my observations.
On several occasions when he was in my car, the above-described scenario would take place. In each case, he noted that there were no police cars–either marked or unmarked–in our vicinity as we cruised along the Interstate for several miles while the radar detector beeped continually.

After seeing that he was also intrigued by this situation, I asked him to log the makes and models of cars near us every time that this happened.
Naturally, there was always a wide variety of makes and models with which we were sharing the road, but only bit of commonality among all of these cases was that there was a late-model Audi sedan near us in every instance.

I had almost forgotten about this conundrum until earlier today. As I drove home from the supermarket, along a road where there is no place for police cars to hide, all of a sudden my radar detector started sounding a “K band” alert. Sure enough, as soon as I turned a corner, there was a late-model Audi A4 right in front of me. For the next 5 miles or so, as I followed him along a virtually empty rural road, the radar detector continued to sound-off. If I backed-off and increased my following distance, the signal became slightly weaker. When I closed the gap and got closer, the signal became stronger.

Finally, at an intersection, the Audi turned left while I continued straight ahead. Within less than 10 seconds, the radar detector stopped sounding-off.

Does anyone have any theories regarding why late model Audi sedans (but not other makes or models of cars) cause my radar detector to sound-off?

Probably has to do with the collision avoidance system built into the Audis. Some systems use a simple form of radar, and I’m guessing Audis frequencies are using the same bandwidths that the police detectors use.

Thanks, DrRocket!
That makes a whole lot of sense, and I hadn’t considered this possibility.

Maybe you could reprogram it to say “Achtung!” instead of just beeping.

It’s not just Audi’s. Cars with adaptive cruise control use radar technology to help maintain spacing between cars in front and behind while cruise control is engaged. Volvo, Kia and a number of other manufacturers are using it now. A more expensive radar detector will improve things for you. I had to ditch my old Whistler detector because it could not filter out those signals at all. My Escort 9500IX is much better at ignoring them.

My Escort detector did the same thing but on the laser band. My guess is that it’s being triggered by LED tail/headlights rather than collision avoidance.

Lucky you don’t live in the new world where laser speed readings are the norm. Some chain stores used to give a false positive also. Any one else hear the annoying high pitch of security systems in the 70s and 80s?

It’s the Audi “need for speed®” option. It causes other cars in the vicinity to slow down so that the “radar” equipped Audi’s can make better tine. See your Audi dealer, or take two aspirin and call him in the morning.

“A more expensive radar detector will improve things for you”

I’m sure that you’re correct.
The unit that I am using is a fairly old Uniden model that has saved me from several tickets, but–after more than 10 years–has clearly outlived its usefulness.

I think that I am going to treat myself to a new Valentine unit, unless somebody has a better suggestion.

The K band radar is 25.125 Ghz, reserved for stuff called SRD’s or Short Range Devices. Low power broadcast radios “unlikely to interfere with other devices on the same frequency” per the specs I read (yeah, right!). It can be used for radar sensing because of this, like the police radar. This technology has been used on cars for quite some time now. Apparently Audi’s supplier decided to use that frequency. Not every car radar does. Delphi has offered car radar since about 1999 uses the 76.5 Ghz band. Other suppliers use 24 Ghz versions.

This link to a PDF chart shows other suppliers with the 24 Ghz versions.

If anyone can filter out the useless noise in the radar world from a real signal, Valentine, can but they take pride in the ultimate sensitivity of their radar detector. So they may detect the Audis, but maybe they’ll point an arrow right to them and tell you a distance so you can decide for yourself.

Any one else hear the annoying high pitch of security systems in the 70s and 80s?

I still hear them now. I remember complaining that it was hurting my ears when I was a little kid, and my mother wouldn’t believe me because she couldn’t hear them at all. Now I’m older than she was then and I can still hear the stupid things. And I only stopped hearing that horrible whine when someone left a monitor on after turning the computer off because they stopped making CRT monitors.

Maybe I’m Batman!

The chain stores gave a false positive because old automatic door sensors were just a radar gun mounted above the door. When it got a return signal from someone standing in front of it, it opened the door.

Radar detectors today are virtually useless anyway. The laser detector only goes off when the cop is painting you with a laser already, and the instant-on radar technology has gotten good enough that oftentimes by the time your detector alarms for that, the cop’s already locked in your speed.

If you must speed, pick a rabbit and follow him. A rabbit is the clueless dope who whizzes by you at 80mph. Follow 1/4 of a mile behind him and he’ll be the first one the cop sees and take the ticket for you. :wink:

I recall reading about the demise of the radar detector several years back when these systems first started hitting the road. It seems the detector manufacturers are responding with better filtering algorithms and user features such as “Traffic Filters” that can minimize or eliminate false alarms from K band radar used in lane deviation and collision avoidance systems.

I gave up on detectors many years ago, primarily due to instant on systems the police now use, and employ shadowfax’s approach. It doesn’t work very well when there isn’t much traffic but it’s a good approach otherwise…

Any one else hear the annoying high pitch of security systems in the 70s and 80s?
I remember complaining that it was hurting my ears when I was a little kid

I remember going to department stores in the late '60s to early '70s being an unpleasant experience, when I was a pre-teen.
I remember some convenience stores more recently using near-ultrasonics to deter teens from loitering outside the stores.

“If you must speed, pick a rabbit and follow him”

The trick is to never be the fastest one on the road–IMHO.

“Radar detectors today are virtually useless anyway”

I’m going to disagree with that.
In my town, which is very rural, there are long stretches of roads going past nothing but farmland, yet the speed limit is 30 mph! I thought that I knew all of the places where the cops hide in order to set up their radar, and I always slow down before I get to those hide-outs. However, w/in the past month or so, they have found 2 new hiding places, and I wouldn’t have known about their presence–in timely manner–without the aid of my radar detector.

I once owned a fairly sophisticated GPS that had a built-in radar detector that monitored most, if not all, the band frequencies used by law enforcement. It also picked up the signals from adaptive cruise controls, automatic doors and some security systems in large buildings/shopping centers and malls. The warning signal never shut up unless I was on the open interstate. I bought a less sophisticated GPS and it works great without all the warning signals. It also lets me know where the nearest gas station, restaurants and rest areas are with distances displayed. Since I keep up with the flow of traffic…I really don’t need a radar detector.

"If you must speed, pick a rabbit and follow him. A rabbit is the clueless dope who whizzes by you at 80mph. Follow 1/4 of a mile behind him and he’ll be the first one the cop sees and take the ticket for you. ;)"
That’s what I’ve been doing for years.

In my town, which is very rural

There’s the trick. The last time I had a radar detector was when I was working for a TV station in the middle of farm country. It’s useful there because the cops will sit there and just spam their radar all day long, so you know where they are sometimes miles before you get to them.

In the urban environments I drive now, the equipment and techniques are sophisticated enough that a detector isn’t much use.

That said, I really don’t speed much anymore unless it’s an emergency. I save the fast driving for track days.

Quoting @VDCdriver

I think that I am going to treat myself to a new Valentine unit, unless somebody has a better suggestion.

My younger son, the speed demon, uses a Cobra. Swears it’s as good as a Valentine at a much lower cost. Of course Valentine offers that “We’ll pay the ticket” guarantee. Does anyone know if they really pay 'em, or do they have lots of fine print in the guarantee? I asked him if he’s ever experienced the Audi “need for speed” phenomenon. He said he hasn’t.

I have a Whistler which is very good but prone to false alerts. I also have an Escort 9500IX which I highly recommend. It is super sensitive, picking up troopers two to three miles away, and it is super quiet due to built in GPS that locks out known false signals. It also has a red light camera database that is extremely useful and it rejects Traffic Control Radar that is commonly used in many cities.

I don’t ear the high pitch alarm any more, sorry you do, I know I would leave those stores because it made me feel like my brain would turn into jello. Maybe we are 1%ers at something because I don’t think I ever met any one else that heard them. Nice info about the doors, makes sense. @shadowfax