# Officer Does Not Know the Speed Limit

1. Member
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Jul 2010
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62

## Re: Officer Does Not Know the Speed Limit

I didn't say I was "entitled to a buffer", I simply mentioned that there are inaccuracies that go beyond just the tuning of a radar gun, thus the reason for buffers to be in place.

2. Senior Member
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## Re: Officer Does Not Know the Speed Limit

Quoting fastline
I didn't say I was "entitled to a buffer", I simply mentioned that there are inaccuracies that go beyond just the tuning of a radar gun, thus the reason for buffers to be in place.
But you're still inventing a concept that doesn't exist. There is no requirement for a "buffer."

3. Member
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Mar 2019
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50

## Re: Officer Does Not Know the Speed Limit

In any measurement anyone has ever conducted there was some amount of uncertainty involved. If I use a glass measuring cup to measure a cup of water I'll know I have about 1 cup but the uncertainty in this measurement may be +- 5 tbs, if I use a graduated cylinder it may be +- 1 tbs, if I use a very accurate and precise scale it weight the water and then calculate it's volume it may be +- .1 Tbs but never can I be entirely certain that I am measuring exactly 1 cup of water. It's simply impossible to do. What's important is that the measured value and its uncertainty is acceptable for the situation.

The NHTSA requires that the uncertainty of a stationary speed measuring device is at most +1 mph and -2 mph.

If the officer used a moving radar unit, the unit relied on both the speedometer measurement of the vehicle and the radar measurement of the radar. Uncertainty is exacerbated when a measurement relies on more than one measurement device. Speedometers can inherently become less accurate since they are based on the rpm of the drive train and the circumference of the tire. The circumference of a tire can change quite dramatically during its service life. I would estimate the speedometer in an average car over the life of a set of tires to be +-2 mph or potentially more. This code requires that buses have a speedometer that is accurate to a range of +- 5 mph. A recently calibrated police unit may have an uncertainty that is significantly less.

This uncertainty will create the "buffer" fastline is talking about because it casts doubt on the officers contention that the defendant was traveling exactly 40 mph. How large this amount is I do not know, the defendant would have to research it but the judge will likely have their own idea of this in their head. Which may or may not be enough to warrant an acquittal or dismissal. I mean surely if one was given a citation for 1 mph over most judges would dismiss it right?

4. Senior Member
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## Re: Officer Does Not Know the Speed Limit

Moving radar units do not rely on the car's speedometer. They compute the unit's speed itself along with the difference between the target. And so NHTSA says "don't use a radar if it's not with 1 mph for stationary or 2 for moving" but that doesn't say that this is what the accuracy is determined to be, but most units are within a mph either way, and that's not going to mandate a six or ten mile per hour buffer.

You are missing the point that the is not charged at 40 MPH. He is charged at 50 in what appears to be (based on the poster's statement) of either a 45 or 50 zone. That's way more than is required for even the NHTSA-compliant radar units or even pacing require (we're talking about 11% over the limit).

5. Senior Member
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## Re: Officer Does Not Know the Speed Limit

Fastline, can you please post the statute for which you were written up.

Based on the location of the incident, which should be on the ticket and to which the cop will also have to testify, Google photos and your own photos, you should be able to prove the speed limit was 45, and not 40, so at least you shouldn't get a moving violation.

As for the insurance, just renew it ASAP and bring proof with you to the trial (proof that you have it, not proof of when you extended it). Hopefully the judge will not insist on whether you had it at the time and will just assume you just didn't have the proof with you. If he asks you point blank if you had it at the time. I guess you'll have to admit you didn't. In that case, proving you only hadn't had it for 23 hours should be helpful, which is why I told you to renew it ASAP.

6. Member
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## Re: Officer Does Not Know the Speed Limit

8-1558 is the cited statute. Because I drive this road daily, I verified it again yesterday. Not only is is posted 3 TIMES, there is literally a 45 sign 500ft from where I was cited. There is no question on that matter.

As for the insurance, I am waiting for my insurance guy to call me to verify this.

OK, I did verify I HAD insurance! That is a relief!

7. Senior Member
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## Re: Officer Does Not Know the Speed Limit

This is even more confusing. You're cited for a maximum speed law for which neither 40 nor 45 apply. What was the exact address so we can look at it in google maps.

8. Senior Member
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## Re: Officer Does Not Know the Speed Limit

pppffftttt….

The cop had difficulty reading numbers - the evidence exists that supports that. He saw 45 on the speed limit sign but read 40. The cop was not operating effectively. Obviously when he saw 50 on the radar, he must have misread that as well. Argue that the cop needs new glasses....

9. Senior Member
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## Re: Officer Does Not Know the Speed Limit

Quoting Guybrush
pppffftttt….

The cop had difficulty reading numbers - the evidence exists that supports that. He saw 45 on the speed limit sign but read 40. The cop was not operating effectively. Obviously when he saw 50 on the radar, he must have misread that as well. Argue that the cop needs new glasses....
You won't get anywhere with that line of argument. The question is why he was written up for being in excess of maximum speed at 50MPH unless this was an urban street.

10. Member
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## Re: Officer Does Not Know the Speed Limit

Something that has always bugged me, and really should bug every American and attorney, is how the government has enacted their own power to amend complaints on the fly. Even when I walk into to trial refuting the evidence, which is what is on the citation, the prosecutor will just say, "your honor, I would like to amend this complaint to this".... The judge asks if I object, and of course I do. The just cares none, overrules my objection, and they can just tune it up how they want.

This day in age is pretty sad that cops can do shoddy work that affects people's lives, and the government simply accept that "everyone makes mistakes"...... Tell that to the victims.........

I am on a light deal here but but honestly, the cop can't 'reed guud', and doesn't even know the statute he is enforcing, but it matters none. If I was that bad at my job, I wouldn't have one.

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