Q&A - Questions About Speed Measurement

Q&A ImageI was recently issued a speeding ticket with a fine amount of $138. I was driving westward on the left lane behind a pickup truck. I was looking for a street sign, so I slowed down and changed lanes to the right so that vehicles behind me could pass.

Immediately after I changed lanes, I saw an officer on my lane motioning to pull over.

The pickup truck in front of me on the left lane pulled over but the officer motioned for me to pull over so I pulled over too behind the pickup truck. The officer let the pickup truck go and told me that I was over the limit as I moved to the right to overtake the pickup truck.

I do not know why the officer assumed that I was overtaking the pickup truck. It was ahead of me all the time even when I had changed lanes and when we pulled over.

It is also surprising how the officer was able to determine that I was speeding considering that I was pulled over immediately after changing lanes.

How could my speed have been recorded when I was behind the pickup truck and was pulled over the second I changed lanes to the right?

Can radar/laser guns measure accurately in 1 second the speed of a car that is changing lanes?

If so, could my motion of changing lanes have affected the speed measurement of the radar/laser gun and added to my actual speed?

Can this violation be cancelled?


Speed Measurement

Both radar and laser are virtually instantaneous in the measurement of speed. The difference between them is that laser may be aimed to target single vehicles in the traffic flow where radar essentially bounces off of them all and it is up to the operator to determine what the speed of the target vehicle is by adding observation to the readings.

Your vehicle would have been simple to single out with laser being worked at a slight angle to the roadway. In this case it actually works to your advantage as your speed measurement is reduced by the cosine of the angle. It makes very little difference until a large angle is reached.

All tickets may be cancelled. This needs to be done by the issuing officer. No one else has the authority to do so.

To know more about how the officer arrived at the decision to issue you the speeding ticket, simply request disclosure. There is information on how to do that by searching on "disclosure" using the search blank on the top left of this page.

Remember also that any speed over the limit is speeding according to the law. You must travel at or under the speed limit.

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