Sgt Al's Blog: DEAR SGT. AL: HOW DOES AN OFFICER CONDUCT SPEED ENFORCEMENT?

DEAR SERGEANT AL: How does a police officer conduct speed enforcement? What are the methods officers use to enforce speed limits? – SPEED ENFORCEMENT EXECUTED DIMENSIONALLY CERTIFIED LAW ADJUSTED PROGRESS TOWARD RESTRICTIONS AS POSTED, SALLY

DEAR SPEED CLAP TRAP SALLY: There are four main ways a police officer conducts speed enforcement: radar, laser or lidar, timing (where from the air or fixed point the officer times a vehicle between two fixed objects) or calibrated speedometer (clocking). Let’s go one by one (for the most part):

1. Enforcement by timing two fixed points: This is what happens when you see signs like “Speed Checked by Aircraft.” This is the simplest and most unobtrusive way to do speed enforcement, but the most expensive way if police aircraft is used for obvious reasons. This requires at least two officers, the observing and the issuing officer. The observing officer, either by secreting himself on the roadway or by aerial observation in an aircraft, will observe a speeding target vehicle on the ground. He makes an estimate how fast the target vehicle is going. When the target vehicle passes a fixed point, something like a mile marker, landmark, or paved speed markings on the road, he activates a timing device (stop watch) and times the distance traveled up to the second fixed point. Knowing the distance between the two fixed points he can easily determine how fast the target vehicle is speeding, simple math. He radios the issuing officer to pull over the target vehicle and the issuing officer issues the motorist a violation. Plain and simple, no electronic device to complicate things, and difficult to beat in court.

2. Calibrated Speedometer (Clocking): The patrol vehicle has a calibrated speedometer (either usually the original equipment in-dash speedo or now less often an after-market separately installed speedometer). The vehicle is rolled onto a calibration machine on a regular documented basis to ensure the speedometer is working within usually +/- 2-3 miles per hour. Out on patrol, the officer paces his vehicle usually within close observation of the target vehicle for a certain distance. When subpoenaed or testifying in court the officer must bring a documented abstract that the speedo was working correctly at enforcement time and periodically over the life of the car. This is also clear cut and usually hard to beat.

3. Radar or Lidar: The most popular way to conduct speed enforcement. Whether using a radar or laser (lidar) enforcement device, a police officer must conduct a series of tests to the device before, during, and after the enforcement to ensure that the machine is working correctly. First is the light test to ensure that all the LED indicators on the face of the machine are working correctly. The next is an internal calibration test to ensure the measuring components inside the machine are working correctly, and usually that entails just flicking a switch. With a radar device, the officer uses a tuning fork that matches the unit and pitches it to simulate the sound waves passing through the antenna. These three tests are required before he begins enforcement. When he’s out on the road with a radar device he must adjust his antenna to make sure he gets the lanes of traffic he's targeting and nothing else, including the opposite lanes, if any. He has to wait for a lull in traffic on both sides to ensure he’s getting the target lanes. He’s now established what’s called the zone of influence. When he’s pretty sure he has the lanes he wants to enforce (the zone of influence) this is where he’ll wait for a speeder. He makes an estimate first of how fast the target vehicle is speeding before the target vehicle enters the zone of influence. After the estimate, the target vehicle locks into the zone of influence with the reading the device gives him. If the reading and the estimate are within +/- 3 miles per hour, he’s got a good speeding ticket to issue. At the end of the tour he must conduct all the same tests to ensure the device was working even after the enforcement. He must also conduct the internal calibration and light tests after each ticket. All of this must be documented in his notes. He must bring an extraction of these documented tests to court every time he testifies or upon subpoena. A little trickier to convict, but with a good note taker, practice, and good testifying skills, any officer can become a pro at hammering a motorist in court.

4. Issues just with Lidar: With a lidar device an officer basically does the same tests above except for the tuning fork, so there are additional light calibration tests he must perform. A lidar device works similarly to a handheld radar unit, except instead of a zone of influence he has to aim the device right on the speeding target to get a reading, usually on the bumper or license plate. He makes an estimate, and then locks the device. If he’s within +/- 2-3 miles per hour, the officer is good to take out his pen and ticket book.

There you have it SALLY, you are WARNED: I give you this information freely and willingly because in spite of having the knowledge, all you speeders out there won’t use it toward your advantage and will speed anyway. It’s just a matter of time before you get caught and this information won’t make a difference to have all of you in court to most likely lose your speeding case. And that’s fine with me! Safe driving and good luck!