Photo Radar Margin Of Error
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Radar Gun Accuracy
the vehicle is not traveling directly at the radar the relative speed is slightly lower than actual speed. The phenomenon is called the Cosine Effect because the measured speed is directly related to the cosine of the angle between the radar and vehicle direction of travel or speed vector. The greater the angle the greater the speed error and the lower the measured speed. A cosine angle of 90° has 100% error, how to fight a radar speeding ticket in court speed measures zero. Figure 2.1-1 -- Cosine Effect Setup vo = Target Speed a = Cosine Effect Angle R = Target Range to Radar d = Antenna Distance to Middle of Target Lane CALCULATOR Measured (Cosine) Speed from Angle Target Speed: MPH KPH Knots ft/s units Cosine Angle: Degrees Measured Speed Calculate / Re-calculate CALCULATOR Measured (Cosine) Speed from Setup Target Speed: MPH Target Range: feet Radar Distance to Lane: feet Measured Speed Speed Drop Rate Cosine Effect Angle Calculate / Re-calculate The cosine effect angle is the angle between the radar antenna and the vehicle direction of travel. The angle depends on vehicle range and radar antenna distance from vehicle lane center. The antenna pointing angle is completely irrelevant, only the angle to the target vehicle matters. The cosine function is always between 0 and 1. The cosine of 0° is 1, measured speed is actual speed. The cosine of 90° is 0, measured speed is zero. The closer the angle is to 0° the more accurate the speed measured. The cosine effect applies to both microwave and laser radars. Photo radars are Across the Road Radars that angle the beam across the road, typically 20° to 23°. As a vehicle passes through the beam the measured speed is changing and spread
officer calibrated her device at the start of her shift, and the posted speed limit was 35 kph, what reading on the device lidar speed measuring device performance specifications would ensure that the target vehicle was moving at least 36 kph?UpdateCancelAnswer
Speed-measuring Device Performance Specification: Across-the-road Radar Module
Wiki2 Answers Miles Gordon, Certified traffic radar operatorWritten 13w agoWhat is the margin of error of police radar?Assuming
Moving Radar Accuracy
the officer calibrated her device at the start of her shift, and the posted speed limit was 35 kph, what reading on the device would ensure that the target http://copradar.com/preview/chapt2/ch2d1.html vehicle was moving at least 36 kph?Thanks for the A2A. This might be dependent on your state, but zero margin of error where I work. I’ll explain how it works for me (or worked, since I haven’t shot radar in some time).I have two tuning forks; one calibrated at 35 mph and one calibrated at 55 mph. If my radar https://www.quora.com/What-is-the-margin-of-error-of-police-radar doesn’t test EXACTLY at those speeds every day when I test my radar, I don’t use that radar (this has never happened; they’ve always tested spot on). The tuning forks and the radar units are sent off for certification/calibration twice a year. I test the radar with the tuning forks at the beginning and end of each shift.As a function of physics and geometry, discrepancy in reported speed vs. actual speed is going to benefit the driver.One well-known example is the cosine effect. If I’m stopped on the side of a road, and a vehicle is traveling along the road toward me, the vehicle isn’t traveling exactly toward me, it’s an oblique motion, however slight, and the angle increases as the car moves closer to me. This doesn’t matter if the vehicle is farther away, but as the vehicle moves closer (assuming constant speed), the reported speed will go DOWN an mph or two. This diagram may help (radar class involves a lot of geometry).So to answer the second part of your question, I’m not ex
Search Forum Traffic Law Moving Violations, Parking and Traffic Tickets Speeding Tickets: Arguing Radar Margin of Error in Defense of a 102 MPH Speeding Ticket If this is your first visit please consider registering so that you can post. Page 1 http://www.expertlaw.com/forums/showthread.php?t=159853 of 2 1 2 Last Jump to page: Results 1 to 10 of 18 Arguing Radar Margin of Error in Defense of a 102 MPH Speeding Ticket Share Thread Tools Email this Page… Display Linear Mode Switch to Hybrid http://www.realclearscience.com/blog/2013/03/how-i-used-physics-to-beat-a-speed-camera-ticket.html Mode Switch to Threaded Mode 06-11-2013,08:13 PM #1 bradnico View Profile View Forum Posts Private Message Junior Member Join Date Jan 2008 Posts 7 Arguing Radar Margin of Error in Defense of a 102 MPH Speeding Ticket My question how to involves a traffic ticket from the state of: California Kern County Court have sent me a letter with $859 fine and 2 points. I've spoken to court who said I can file a Trial by Written Declaration. Whilst I was well over the 70 limit I slowed down every time i was nearing 100 and do not believe i exceeded 100 mph and the radar gun was not completely accurate. I plan to argue there was a margin of error 2-3 mph margin or error (which radar guns can have) in my statement on the TR 205 creating reasonable doubt and lower the conviction. Does anyone know where I can find any boilerplate legal language that I can use in my TR 205 statement using this argument? 06-11-2013,08:38 PM #2 jk View Profile View Forum Posts Private Message Senior Member Join Date Jan 2006 Posts 33,621 Re: 102 MPH Ticket on I-5: Radar Margin of Error Defense in Tr 205 Statement a claim is meaningless without proof of the claim. To make a valid claim you would have to have the spec manual for the SMD and be able to cite the claims made in the spec's. it is also more likely your speedometer has a greater margin of error than the radar unit. do not believe i exceeded 100 mph you don't believe you did? If you cannot even say with certainty you did not exceed 100 mph, even if it is based only on your speedometer, your argument is meaningless. I know if I never look at my speedometer I can make the same argument since I was never aware I was going above any particular speed. That does not a defense make. 06-12-2013,11:12 AM #3 bradnico View Profile View Forum Posts Private Message Junior Member Join Date Jan 2008 Posts 7 Re: 102 MPH Ticket on I-5:
Earth Does Not Orbit Around the Sun »CommentsHow I Used Math to Beat a Speed Camera TicketPosted by Alex B. Berezow March 21, 2013Seattle is a city in serious need of cash. To make up for its budget shortfall, it has increased street parking rates so incredibly high that drivers feel as if they are the victims of a highway robbery.* But the most controversial measure, by far, has been the implementation of red-light and speed cameras.City governments justify the use of traffic cameras because they claim it increases public safety. However, for both red-light and speed cameras, the data on this is mixed. Of course, regardless of whether or not the cameras actually serve a greater purpose, cities are quite pleased by the substantial bump in revenue they receive from them.Recently, I found myself on the wrong side of the law. (Well, legally, traffic camera tickets fall under the purview of civil cases, not criminal cases.) The citation said I was traveling 30 mph in a 20 mph zone, and for that, I received a whopping $189 fine. But there was a big problem with the photos they provided as "evidence": They didn't really prove their case.The first thing I noticed were the timestamps. The first photo was marked 04:14:19.7 PM, and the second photo 04:14:20.2 PM. That means it took 0.5 seconds for the camera to take two successive pictures of my car. In order for me to verify if the speed camera was accurate, I needed to know the distance my car traveled in that time period. But, that information wasn't provided in the citation. The second thing I noticed was the poor quality of the photos. The angle and the lighting make it very difficult to determine how far my car traveled. Based on a landmark (a parked car), it appears as if I traveled about one car-length in 0.5 seconds. The type of car I drive is typically about 15 feet long, so that means, based solely on the crude photographic evidence, that I was traveling 30 feet per second. Crunching the numbers, that converts to 20 mph. In other words, the photographic evidence didn't support their case that I was speeding. Obviously, th