OI? and court accepting explanations

[ekgrow21]

What is the name of your state (only U.S. law)? Indiana

I received a speeding ticket for 65 in a 55 constructions zone. My trial date notice says Offense: SPEEDING: CERTAIN STREETS/OI. Does OI mean Ordinance Infraction for the construction zone or did the construction zone get overlooked. It said construction zone on my ticket.

Another topic. I am a college student and have taken light physics. There was dust (from the construction) in the area I was clocked and I as clocked at an angle. This would throw off the reading, but would they accept my explanation since I am not a professional on the subject. My physics professor said he would help me out but I don't think I can get him to show up at my trial. Anything I can do?

[racer72]

Unless the dust was solid, forget that excuse. Also, radar read from an angle will record a speed lower than the actual speed, not higher.

[ekgrow21]

I am curious what other matter state could dust be in? And everything effects the speed of light. Even the air slows light down. So why would the dust have to be solid?

If I prove the validity of the radar was not reliable how could the reading be accepted even if it would read higher straight on?

[racer72]

Radars operate with a radio frequency, not light. Same reason you can recieve your favorite radio station in your house. Solid dust would reflect a portion of the RF energy back to the radar gun giving likely showing a speed of 0.

In most cases where a radar is used to determine speed, it is not considered the primary method of determining the vehicle speed. The officer with appropriate training will make a visual estimation of one's speed then use the radar to confirm his suspicion. As far as angles go, radar guns generally have an accepted angle allowance of up to 25 degrees, depending on the manufacturer. It is accepted that an officer cannot take a reading head on, this would involve standing in the middle of the road if the road is straight. This is why long sweeping curves on highways are favorite spots to catch speeders, the officer can stand on the side of the road and still radar vehicles for that split second they are heading straight towards them.

[Maestro64]

You on the right path radar signal can be affected by a number of things, fog and rain can affect the signal this is why some states require the officer to record the whether conditions. What happen is as the wave travels is ionizes the particles in the air and this can adversely affect the reading.

But to your point the judge will not allow you to testify to radar accuracy, since you are not an expert.

Also, I/O could me that is instance on the radar unit.

The of angle error is called cosine error which if you do your math it means the greater the angle the low the speed the radar will measure.

[FlyingRon]

Any radar not reflected to the gun is loss. You want it to be reflected to work.
Yes, radio waves have different propagation in differing media as does light, but still you're not talking about a significant error. The radar gun isn't measuring the time it takes a round trip to occur. It's measuring the shift in frequency based on relative movement of the radar and the target.