Is the speedometer incorrect, or police radar?

[Ghettosled]

Driving from Cleveland Ohio to Albany NY, I reached the outskirts of Albany at about 11:30pm. I have the cruise set for 71 in the 65 zone. Fast enough but not too fast. I'm driving in the left lane creeping past a newer style Cherokee, crest a hill with a trooper perched on top. I didn't think twice about it, until he pulls me over. He said I was traveling at excessive speed. I said I didn't think 71 was too fast but I guess I was wrong. He said he radared me at 81. Politely I said I don't mean to question him, but my cruise was set at 71 so asked to see the radar, but apparently the speed doesn't save. My wife and two kids in the car, no other cars near us on the highway. I haven't had a ticket in about 12 years, but he let me off with a license plate obstruction ticket (I have smoked plastic covers).

How could the radar gun be that far off, or my speedometer?

 

[Mark_888]

Driving from Cleveland Ohio to Albany NY, I reached the outskirts of Albany at about 11:30pm. I have the cruise set for 71 in the 65 zone. Fast enough but not too fast. I'm driving in the left lane creeping past a newer style Cherokee, crest a hill with a trooper perched on top. I didn't think twice about it, until he pulls me over. He said I was traveling at excessive speed. I said I didn't think 71 was too fast but I guess I was wrong. He said he radared me at 81. Politely I said I don't mean to question him, but my cruise was set at 71 so asked to see the radar, but apparently the speed doesn't save. My wife and two kids in the car, no other cars near us on the highway. I haven't had a ticket in about 12 years, but he let me off with a license plate obstruction ticket (I have smoked plastic covers).

How could the radar gun be that far off, or my speedometer?

It's not your speedometer. It was either a problem with the radar, or a user error when using the radar (such as radar moving while taking the reading).

You should be able to verify your speedometer with a GPS that calculates your speed. I have a cheap ($90) Garmin model that will do that.

 

[Sal Collaziano]

Yeah, I seriously doubt your speedometer would be ten miles per hour off...

 

[kn5owa]

It is a fact of life that the cop is right whether he is right or wrong - the radar is just a mojo/juju gadget - good for shakedowns.

I worked with, and designed, microwave equipment. Not a whole lot different than witchcraft.

Cops like to say that radars & lie detectors are infallible. But guess who operates both?

 

[DavidHanLee]

Does OP have aftermarket wheels and tires of sorts?

I'm not too familiar with this but larger wheels or tires can impact the accuracy of the speedometer.

 

[Gunkk]

Old cop trick: scan DOWN the car with the radar, so the radar reflects off the top of the windshield, then you, then the hood, then the grill... easy way to fake it to make it look like the car was moving faster than it was.

Older cop trick: Lie.

 

[landtuna]

One question that always comes to mind in situations like this:

Was it worth the extra time possibly saved by driving six miles over the speed limit? Why not just go with the speed limit (unless other heavy traffic is pushing up your tailpipe).

Not trying to be a smart ass. Just wondering why people trying to squeeze every last ounce out of speed and time when the numbers are so small. I mean, it isn't like the Cannonball Run, right?

 

[Nikgen]

One question that always comes to mind in situations like this:

Was it worth the extra time possibly saved by driving six miles over the speed limit? Why not just go with the speed limit (unless other heavy traffic is pushing up your tailpipe).

Not trying to be a smart ass. Just wondering why people trying to squeeze every last ounce out of speed and time when the numbers are so small. I mean, it isn't like the Cannonball Run, right?

At least in NJ, if you drive the speed limit, you'll be holding up traffic and might even get rear ended . Almost no one drives the sped limit on the highways - 70-75 is the average speed regardless of a 55 or 65 mph limit.

 

[Sal Collaziano]

At least in NJ, if you drive the speed limit, you'll be holding up traffic and might even get rear ended . Almost no one drives the sped limit on the highways - 70-75 is the average speed regardless of a 55 or 65 mph limit.

Florida as well. Nobody goes 55 on the highway. Not even the oldest grandmother on the road.

 

[Operationdoomsday]

One question that always comes to mind in situations like this:

Was it worth the extra time possibly saved by driving six miles over the speed limit? Why not just go with the speed limit (unless other heavy traffic is pushing up your tailpipe).

Not trying to be a smart ass. Just wondering why people trying to squeeze every last ounce out of speed and time when the numbers are so small. I mean, it isn't like the Cannonball Run, right?

Here in Southern California the speed limit on most freeways is 65, but the average person goes 70-80. If you were going 65 you'd be endangering others by not going with the flow of traffic. I don't think the OP was going fast what's so ever, especially with no one on the highway.

Seems suspect that the officer wasn't able to show you how fast you were going, how would they have any evidence if you were to fight the ticket in court?

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[Ghettosled]

Thank you foe the reasons and causes.
Stock wheels and tires.
I wonder if it was a "this guy is from another state hundreds of miles away, odds are they won't show up to court to contest the ticket".
As for speeding, on a 8 hour, 500 mile trip - an extra 6mph saves 50 minutes of travel time. With kids in the car, this makes a difference.
Can't wait to see what the fine is. I have to call and plead guilty first.

 

[kn5owa]

Seems suspect that the officer wasn't able to show you how fast you were going, how would they have any evidence if you were to fight the ticket in court?

I ain't giving my age, but I'm experienced enough to write a book based on all the silly crap I've gotten from cops. They'll say and do anything.

 

[84FordMan]

Most speedometers have a positive bias programmed into them (GM does this a lot), essentially if your speedo says 70 MPH, you are probably really going 66 or 68 MPH.

Fight the ticket, ask to see documentation of when that particular gun was calibrated and when the officer was last certified to use it.

 

[jlindh]

My '12 Genesis speedo reads exactly the same as my GPS. Dead on.

 

[kn5owa]

Fight the ticket, ask to see documentation of when that particular gun was calibrated and when the officer was last certified to use it.

And bring your checkbook.

However, if the cop knowingly writes a phony ticket, there is a good chance he'll be a "no-show", knowing of course that you'll will still have plenty of hassle and inconvenience.

 

[Ghettosled]

Fortunately or unfortunately he 'cut me a break' and wrote the ticket for obstructed license plate and not for speeding. I guess a quick and easy way to ensure revenue for the state/city? Either way, I probably would not have driven the 8 hours back to Albany just to fight the ticket. I wish my dash camera has speed recorded in the video. I should see if I still have this video clip or if it's already been recorded over.

 

[Fredder]

My 2011 3.8 shows I am travelling at 3 Km per hour faster than the GPS reading
In effect, I am under what I think I am going at.

 

[Rey]

Your GPS speed reading is the correct actual speed. Virtually all auto/motorcycle speedometers read high/optimistic, some more than others. Mfgs have erred on the side of overstating speed for as long as I can remember. Hyundai's differential seems to be about 1%.

 

[GensisBoss]

Yeah i dont think its your speedometer cause 81 and 71 is a big difference. that being said maybe the officer was wrong? weird...

 

[kn5owa]

Yeah i dont think its your speedometer cause 81 and 71 is a big difference. that being said maybe the officer was wrong? weird...

Cops are never wrong - if he said you were doing 85, then that's what you were doing.