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Traffic Radar for Motorists, Why 33% of Speeding Tickets are Wrong!   6/25/2003 LLC

WOW! Isn't this amazing? You're looking at a HUD (Heads Up Display) laying flat on the dash in front of the steering wheel! It reflects into the windshield and simulates the main Radar Beam, which is a forward spinning, circular cone as it leaves the radar antennae. By using an active simulator, we can show what's really happening with radar! 

The Red Clock Face, the Blue Spinning Circle, and the Cursor itself form an interactive training aid/simulator.  All three interact with one another as in a patrol car. Move the Cursor and the Red Clock Face moves. When the "second hand's" small red circle (middle of the clock face) moves, the blue circle moves.  Try moving the small red circle of the clock face onto the small white dot near the center of the picture below.  What's happening? What do you see? How do you explain it? What has to move first? How does this relate to Police Radar? In the hillcrest photo below, what do you see that can cause errors? We'll explain more below.  Keep going!

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HUD Radar Beam Simulator/Aid Laying Flat on Dash of Vehicle, Reflecting onto Front Windshield

Move the cursor around slowly, back and forth. The spinning clock pattern is like a Moving Radar Beam (always delayed). Motion lags behind the Officer's intended direction and patrol car's centerline of movement.. Red moves first, Blue second.  Keep Going, you're doing fine! ▼

Red settles down first, Blue second, with always a momentary, computational delay. Short, momentary readings cause errors. That's the reason for 3-5 seconds of minimum Police Officer Tracking History when operating Moving Radar (harmonics are usually momentary).  The radar readout is always "Secondary Evidence". It can only be introduced after good "Primary Evidence," (the officer first actually witnessing and estimating the speed of a moving target vehicle using his/her senses, called "witnessing").  Momentary "sampling" of traffic to get a reading, not allowed. See more in book chapters.

Move the beam around and watch the radar beam form and reform.  It takes about 5 seconds until everything finally settles down to get a good stable reading. The Main Beam's Hot Spot is anywhere inside the Red area. Toward the edge, between the red and blue is what is called "Half-Beam power" where reflections are only half as powerful, resulting in wrong targets being selected, especially on curves/hills. Target size does not matter, it's "reflective capability" that matters. Look at F-117 US Air Force Stealth fighters and bombers.  Large size, virtually NO reflectivity! What are modern vehicles composed of?  Certainly not all metal! A more reflective vehicle can be overtaking your vehicle from behind, reflecting the strongest signal!

The Radar beam spins out out from the antennae in a Counter Clockwise Spiral until it hits a reflective target. If the reflector is good, the beam bounces back to the radar Clockwise. A moving target will "stretch" or "compress" the signal depending on movement away from or toward the radar antennae. It's similar to a train's whistle coming toward you or going away from you. The pitch or tone (frequency) changes. The radar computer calculates the closing speeds. If the math doesn't total up correctly or subtract properly, you get errors! This results in inflated, wrong tickets!

Court Rulings state that the Radar Antenna must be pointed Straight Ahead at Zero Degrees. This is depicted by the small white dot reflected straight ahead onto the windshield in the picture below. The starburst image is being reflected from the black and white Heads Up Display which is laying flat on the dash. Move or position the flat HUD until the white dot is reflected back directly in front of your dominant eye, at zero degrees, straight ahead, just above the horizon, in the windshield. This is the projected Center Line of the Moving Patrol Vehicle. Any speed computed from the Patrol Radar's Side Beam reflection increases the Target Speed in Moving Mode (explained in the book). Notice how the Center Beam is shooting "over" the top of the roadway as the patrol car crests the hilltop. It shoots over the top of oncoming vehicles, maybe yours.  You get the ticket for someone speeding and approaching from behind you!

Now, in the photo below, place the Radar Beam's "red second hand" circle into the center of the white dot just above the horizon. At 1000 feet in front of you, the K-Band Radar Beam width (12 degrees) is over 200 feet wide. X-Band is wider yet (18 degrees), over 300 feet wide. How many moving targets can be in the circle at this distance?  What if the road curves left or right, or intersects high speed roads! Wrong Target! Donut:  

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 It's hard to see, but there is a Microwave Tower Antennae on the horizon straight ahead just to the left of the HUD's white dot. It's pointing right as us. Also notice the metal chain-link fence line on the right side, converging and angling down the hill towards the buildings and curb and sidewalk. Notice how the car to the left may NOT be the speeder.  The driver is within the "half-power" lobe of the radar beam. Move the cursor around pretending to follow the movement of the patrol car, left/right, up/down as it goes over the hillcrest and down the hill.  Notice that the radar beam can be looking at something the officer isn't watching or can't physically see. (The oncoming microwave frequency). (He doesn't notice the metallic fencing) (He thinks the target is the car cresting the hill)  This comes from a true story (39 in a 25 zone). Wrong Target! Actual case.  Dismissed!

Final Test!  Note the time by looking at the second hand on the clock face. Place the Radar Beam's small red circle, sequentially, into the center of all the target numbers (1 thru 5) below. How long did it take you? Your best time? 








NOTE: This should have taken 12 to 20 seconds MINIMUM! 3-5 seconds of Tracking History for each Target!

Which target number is the largest? Which target slants?   Which target is furthest behind"? What about multiple targets, close to one another? Which vehicle would reflect more signal back to the radar? What if the vehicle is primarily non-reflective?  Does physical size really matter or is it reflective capability?

An instantaneous reading can be a Harmonic, a Car at a Much Greater Distance with more reflectivity, or a Patrol Speed Distortion caused by Stronger Side Reflectors. It takes time to get an accurate reading and make an assessment of speed. Primary evidence first, then Secondary radar evidence. Not vice-versa!

Night Time Operations! 1000-1500 feet maximum. Medical Journals and Optometrics/Clinical information indicate that human speed comparison/judgement is difficult beyond 1000-1500 feet, Day or Night.. When it's dark outside how do you measure speed when you have no background comparisons in order to make Primary Evidence judgement calls? This is the required "Tracking History" that is necessary for a conviction in court.

Any questions?  Please email  Dr-Radar by clicking here..

Thanks for taking the time to learn about Police Radar.

RED code  Green code  Blue code Orange code errors are possible. More in future updates and revisions...