Ithaca DWI Lawyer: How Do Police Prove It Was Your Car Speeding on Radar?

Our Upstate New York law practice puts out lots of videos and blog posts about the defense of tickets and DWI. I think understand the legal process and how things work practically helps people make "informed" decisions. Because of that we get lots of questions concerning speeding ticket defense.

A recent inquiry went like this, Hi, my name is Ryan.

I saw your video called "How Do Police Prove You Guilty of a New York Speeding Ticket?"

It is a great video that helped me better understand the laws, good job!

However, I am curious about something.

When an officer uses a radar gun to determine your speed, how do they prove that they were measuring your vehicle's speed and not of another nearby? (emphasis mine)

Your Police Radar Speeding Number is NOT Evidence Until it is Testified TO 

All cases rely upon testimony. Evidence can be testimony of what someone saw, heard, and smelt. All police devices and machines that gather information whether in the form of the speed of a moving car or a sample of someone's breath must follow three things:

1. How was the device or machine used? Every device has a procedure manual and has a protocol for accurate use. 

2. Was the machine or device calibrated? In other words was it working properly, and how was that assured on the date and time in question.

3. Police testimony on how they used it, where they used, and how they verified the evidence. In  most situations the breath test is not the only source of evidence of intoxication or impairment AND likewise the radar or laser unit is NOT the sole evidence of speeding.

Radar Gun Proof of Speeding is NOT the Sole Evidence in A Speeding Ticket Trial

In response to Ryan's question:

They (the police) will have to testify to all the evidence in a speeding case. This is what most people are most confused about. The police must testify to everything. That is, the evidence of speeding not the radar number alone. In New York State they don't just testify to the device (gun) being used and the number it spit out. In addition, first

Foundation of Police Knowledge, Experience, and Training of Estimating Speed Must Be Laid Out

Evidence of a police officer's visual speed estimation requires FOUNDATION be laid of their ability. They MUST say based upon their knowledge, experience, and training they can accurately gauge a car's speed. They will be questioned by the prosecution as to each of these:

What is your knowledge in estimating a motorist's speed?

What is your experience in estimating motorist's speed?

What is your training in estimating a motorist's speed?

They will also likely add that the calculations from one set point to another based upon feet per minute per second. So car's traveling at 55 mph move from point A to point B in x number of seconds while cars traveling 75 mph move from point A to point B in x seconds, this can be a rough estimate. 

Or

That can testify that they followed you and based on their speedometer, again this must be a calibrated speedometer you were traveling at x mph.

I've never seen "just" a radar device number, in and of itself used to prove a speed infraction in a New York State courtroom.

The Defense of Speeding is Contesting the Accuracy of Vision, Conditions, and the Machine
 

That is also how we can contest those calculations, the officer's vision, other traffic being measured by mistake, weather conditions, and equipment fault or not following all the procedures for an accurate device number.