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  Topic Review (Newest First)
08-03-2010 08:39 AM
jimkonst
Quote:
Originally Posted by IMBoring25 View Post
Pacing is why police cars and motorcycles have Certified Calibration speedometers.
True, but we didn't rely on that. It only means it was accurate when it left Detroit. We actually had a mechanic put too large snow tires on our cruisers that changed the speed by about three mph.
We would take the hand held radar and use it to make calibration cards for all the vehicles, because it was not uncommon to find that the radar was removed form our cruiser to be put on another. We had more cars than radar units, and some of us were less inclined to write tickets, so others would take the radar.
I was fortunate to have a chief who resisted the idea of using tickets to tax the people. He left it up to us to decide whether a driver needed a ticket or a warning. The judge was always pissed about it, though, because his expenses were too big for his budget.
07-31-2010 11:39 AM
IMBoring25 Pacing is why police cars and motorcycles have Certified Calibration speedometers.
07-31-2010 09:57 AM
jimkonst
Quote:
Originally Posted by denny6006 View Post
.Oh yeah did you all see the news out of Ohio this week,A judge ruled that the police officers trained in radar had the right to ticket you without the radar gun because their training was good enough for them to be within a 4mph window,once again second hand info,maybe some of you buckeyes can set me straight on this,true or not?
After having read this again, it seems reasonable that an officer without radar, who spotted somebody tearing down the road far in excess of the posted speed limit, say 60 in a 25, or 80 in a 55 mph zone, could testify to the facts and be given credit for his expertise and his powers of observation.
Especially if he could say that tires were squealing, engines were roaring, and pedestrians were scrambling. That the judge would allow it to within plus or minus 4 mph seems reaching. Also, what is not mentioned, is pacing, where the police vehicle takes a position behind the offender and matches his speed. He then compares the speed of the two vehicles. The the only questions are the accuracy of the police speedometer and again, the honesty of the cop.
A cop who is caught lying to the judge might as well find another job...he will never again get a conviction in that court.
07-31-2010 07:52 AM
delawhere I got stopped while on my KZ750 in DE a handful of years ago. The radar, or cops judgement was dead-on to what my speedo was reading...

Luckily, he was also one of the instructors for the motorcycle safety course, and he just gave me a warning, some info on the course and complimented me on the bike!
07-30-2010 03:15 PM
LibertyPilot ^ Well there ya go and there ya have it! I had a really hard time believing that 70 percent were inaccurate. That's just a gargantuan number not to mention a serious litigious liability. If someone could prove that, there goes 100 percent of all law enforcement's credibility. I know I was speeding when I got pulled over, that was a no brainer though. 84 in a 55 - I was much younger then. The cop told me if I was one mile an hour more (30+ the speed limit) he'd could've impounded my car. The last thing he said was, "I don't expect you to drive like a little old lady but 85's too much. Slow it down for me aight?" Fair enough. I really did slow down after that.
07-30-2010 02:27 PM
jimkonst
Quote:
Originally Posted by VN750Rider/Jerry View Post
All radar and laser speed devices do work on motorcycles. But, it is not totally accurate, and operator error will make it more inaccurate. Radar can be made more accurate than it is, believe it or not, when they clock the speed of a baseball in a major league game, they try a lot harder to get it right than the cops do.

I have worked for the City of Chandler for 34 years, know a number of cops, and they explained it to me. Because of the error inherent in radar and laser systems, they set the speed at which they will stop you several MPH above the speed limit. A good estimate from the cops themselves however, is that only about 70% of those ticketed for speeding by the use of radar are actually guilty.

As for just how sensitive radar is, I can tell you that a person on a bicycle will trip the "photo radar" vans they set up along the streets. I've done it. Jerry.
I can't speak for the city of Chandler, but I was a cop and ran radar, both hand held and mounted, for fifteen years.
Our radar was accurate to 1 mph. Radar is better than that, but you can't write a ticket for .1 or .5 mph over the limit. We allowed five mph because
1. The auto might only be accurate to plus or minus 3mph.
2. it was traditional among departments.
3. An elected judge could not be expected to hold a motorist to the exact letter of the law...the intent of the motorist is important to the judge.

Rain or fog do not diminish the accuracy of radar, only its range.

Some radars can be aimed with great accuracy, but the users manual required only (I think) a 10 degree or less angle of projection on those radars I was trained on.

Viewed in one dimension (like a picture on a magazine) a tractor trailer say, 300 feet away is larger than a motorcycle 100 feet away, and the radar will see that larger target, or if it knows there are two targets, will not give a reading for either. This is a safety built into the computer to prevent mistakes of identity.

Radar will give a spurious reading on several different occasions. It can read around corners if the signal is reflected off a shiny sign or plate glass window. If the signal received is from a neon light rather than the return radar signal. (If the hand held radar is pointed at an electric motor such as the police car's heater. my Crown Vic heater could be read as 25 mph,45 mph, or 65 mph, if I remember correctly, then locked in and pointed at whoever).
More important than the accuracy of the radar unit is the consistent use of it by the officer. There is a specific number of tasks he must go through between radar uses that assure the court that he is using and calibrating it properly. When a ticket is beaten in court it is usually because the defense convinced the court or the jury either that the officer did not follow these proceedures or that his word can not be accepted.

As for the Ohio ruling, it is possible that the press reported it accurately, but more likely that they did not. I would not be surprised to discover that there was a narrow definition of when the officer's judgement was sufficient. When I was a cop, it was the opposite. We took pains to say in court that we observed sombody we thought was driving too fast, and only then did we verify it with the radar. The common mistake was to set it to make an alarm if a vehicle was doing, say, ten over, let the radar tell you somebody was speeding, then the officer had to choose who was the offender. That was a recipe for a dismissed charge. By departmental policy we were forbidden to use the pre-set function.

Finally, and not to get in your face, Jerry, but I would say that upwards of 95% of the tickets written by honest, competent officers were accuarate.
07-30-2010 12:09 PM
AJCruzin Absolutely 100% yes.

When he put hte radar gun down and got the look on his face, it was probably because you weren't speeding.
07-30-2010 10:54 AM
LibertyPilot I know for a fact that in Philly they use LIDAR. Its extremely accurate even at long distances and can certainly pick up motorcycles. I got pulled over in the Jeep a while ago for speeding and the cop told me that's what they use. Here's a link to what it actually does:

http://en.wikipedia.org/wiki/LIDAR
07-30-2010 12:37 AM
IMBoring25 There's a radar trailer I go by with some regularity. I don't discern a lot of difference between how it picks up my VN750 vs. my cages.
07-30-2010 12:15 AM
VN750Rider/Jerry All radar and laser speed devices do work on motorcycles. But, it is not totally accurate, and operator error will make it more inaccurate. Radar can be made more accurate than it is, believe it or not, when they clock the speed of a baseball in a major league game, they try a lot harder to get it right than the cops do.

I have worked for the City of Chandler for 34 years, know a number of cops, and they explained it to me. Because of the error inherent in radar and laser systems, they set the speed at which they will stop you several MPH above the speed limit. A good estimate from the cops themselves however, is that only about 70% of those ticketed for speeding by the use of radar are actually guilty.

As for just how sensitive radar is, I can tell you that a person on a bicycle will trip the "photo radar" vans they set up along the streets. I've done it. Jerry.
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