Is it possible that at a certain angle the Prius is not detected on radar? This has happened to me two times where I would drive into my neighborhood and a stand alone mounted speed detection device(installed by the local police department only 2 times that I know of) would not register my speed. I was so confused by this, minutes later I took my other non-hybrid van on the same road and the dectection worked perfect telling me my speed. If so, could it be the slope of the windshield or is my Prius radar really stealth?
I've never experienced that. I've had several instances where I've passed the standalone "radar trailers", and each time it has flashed the exact speed that I was travelling.
The sloped shape of the front end might make the Prius reflect slightly less than a boxy van, but it is by no means a stealth vehicle. Perhaps the speed sign in question had a very high threshold. Tom
There's one of those stand alone signs near my neighborhood which tell you what your speed is. It always sees me, but it does tend to take a bit longer than when it sees my infiniti.
I need to find this out with more testing but the other day my speedo showed 58mph but the radar thingy said 54. I know there is some margin of error but 4mph?
On stock tires? My previous car, rather old, analog spedo, was showing 3 miles less on radar than the spedo.
They see me just fine too as well they should. The speed display's are puttin' out alot of power. My Bel65 Detector goes off way way before I see it. Hotter than a car radar.
Maybe because you were driving in "stealth mode"? If you don't want to stand out better not to be too bold (like your font)
It depends, the RCS (radar cross section) of the Prius is indeed smaller than a box van. if a radar gun is emitting on both the Prius and the box van, the reflectivity signature of the van will trigger a reading on the radar gun. Under this situation, the Prius would be in "steath" mode. Dbcassidy
Yesterday, we were driving along a stretch of road that had an unmanned speed alert trailer. We had barely reached 40 mph. The sign said we were doing 77! The car in front of us registerd 42 and was not a Prius.
If one is coincidentally & legally transmitting at 440mhz at 50 watts or higher, the transmission can ... er, 'deflect' many radar signals. The junk devices sold to the suckers out there, only put out a few milliwatts, so they'e worthless. And if you DO transmit 50 watts on many bands, you better darn well be shielded from the signal.
Consider the angle first. The gun will only be completely accurate head on due to cosine error. In most cases the closer you are, the greater the angular offset and therefore the greater the error in your favor. Ten degrees should give less than 2% error, but 15 degrees works out to 3.4%, 25 degrees is 9.4% if I understand this correctly. A radar sign is not likely to be well calibrated and they tend to use older tech anyway (often X-band from what I pick up.) With regards to the OP it wouldn't surprise me if the Prius signature was smaller than average, particularly if the vehicle does not have a front plate.
Probably X band from what I recall of the sign signals. That stuff can be picked up several miles away (particularly if there is a very low gray cloud layer). I've seen this with the old X band guns used by plant security types as well. I don't know if they transmit a much stronger signal or if it is just really easy to detect from background.
Isn't HARM an air-to-surface missile? I would imagine the resulting explosion of shooting the radar device might chip the paint on the Prius. Not worth it.
