The NMA spells out several proven strategies to fight a speeding ticket in our Fight That Ticket! ebook — a free download for supporting members, a $9.95 purchase for non-supporting members. One such technical defense is based on cosine error. It is an underutilized strategy perhaps because it brings back unpleasant memories of high school math class, or maybe because the error usually produces a lower-than-actual speed reading on a radar/laser gun that already favors the driver.
To first explain what cosine error is and how it can come into play when a law enforcement officer uses radar or laser to gauge the speed of a passing vehicle, we’ll snip a couple of pertinent pages from Volume 2 of Fight That Ticket!:
This page from the CopRadar.com website allows you to dig as deeply into the trigonometry as you’d like. It also provides online calculators to determine measured vs. actual vehicle speed based on the cosine angle. The calculators are helpful if you want to try to avoid unpleasant flashbacks to 9th or 10th grade.
All of this leads to one of the cleverest uses of the cosine error to beat a speeding ticket that we have seen. In fact, we published the following successful defense strategy in the November/December 2005 issue of National Motorists Association Foundation News, the forerunner to the current NMA member magazine, Driving Freedoms. Zamir Bavel incorporated his knowledge of cosine error with strategic questioning to discredit the testimony of the ticketing officer and win his appeal.
A little bit of math mixed with the same courtroom ingenuity may turn out to be your best defense against a speeding ticket someday.