Once you have reviewed the general principles behind the decision of whether or not to fight a traffic ticket, there are additional considerations which relate to whether you can beat a speeding ticket. You should note up front that much of what you may have read on the Internet, particularly that which seeks to convince you to buy a book or publication, overstates your possibility of beating a speeding ticket. If there were easy ways to beat tickets, the information would be all over the Internet for free. There are technical defenses, some of which are outlined quite admirably in materials available for sale, but even when relevant they can often be difficult and burdensome to prove.
A common point of defense to a speeding violation is that there was not proper notice of the speed limit. For example, the speed limit sign might have been hidden by foliage, or may not have been posted in compliance with state or local regulation. Please note that every jurisdiction has default speed limits for unposted roads. Before you raise the defense that a given road appeared to be unposted, you should check to see the consequences of proving your argument to the court. If the default speed limit is 35 miles per hour, and you were ticketed for driving 40 mph, even if successfully proved your defense may nonetheless result in your being convicted for speeding. Please note that an improperly designed or placed traffic sign will not necessarily result in the dismissal of your ticket -- the outcome will depend on state law and the facts of the case.
If you are going to claim that there was a physical problem at the location where you received the ticket, which resulted in such problems as the officer confusing your car with another due to an obstructed view, or foliage in front of a speed limit sign, it will help enormously if you take photographs from the relevant vantage points to document your defense. Such photographs should be taken as soon as possible after the ticket is issued, ideally under the same general weather and lighting conditions that existed at the time the ticket was issued. Please note that the problem may be repaired, particularly if it is temporary in nature (such as a fallen tree branch in front of a road sign), and if you don't act quickly you may not be able to document the problem.
All jurisdictions have basic training requirements for officers who monitor speed with electronic devices, such as laser or radar. They also have requirements for the maintenance of any devices used to monitor traffic. These regulations are available for purchase, and may also be available for review at a local government office (such as a city attorney's office). You can often schedule an appointment at a police agency to review their maintenance logs, or use the applicable public records act (sometimes known as a Freedom of Information Act or Sunshine Law) request to obtain copies of relevant pages.
It is not unheard of for people to establish that the police did not properly maintain such a device, and thus that the reading is not admissible. Please note that this type of defense requires that you be proactive in advance of your court hearing, and obtain relevant police reports, as well as manufacturer instructions, regulations and maintenance logs for the equipment at issue.
It is also worth checking the maximum range at which the device used by the officer is considered functional. If the manufacturer says that the device works at 50 to 600 feet, and the officer claims to have taken your speed at 1,000 feet, it may be possible to exclude the radar or laser reading on that basis.
Another technical defense involves taking very careful measurements and photographs, documenting the manner in which your car approached the place where the police vehicle was parked to monitor oncoming traffic. You would first determine the first point at which the officer could have observed your vehicle. Based upon the speed recorded on the ticket and any relevant manufacturer instruction, you can then determine the distance your car would have traveled between that point and the officer's car. (You may wish to also factor in reaction time, unless the officer was taking a continuous reading, as there would otherwise be a short delay between the time your car appeared and the time the officer activated the speed detection device.) You may discover that by the time the officer could have obtained a valid reading, your car was too close to the speed detection device rendering that reading invalid.
At the same time, such defects may at times be overcome by the officer's testimony - "In addition to the radar reading of 84 mph, I clocked the defendant with my spedometer at 82 mph before I pulled him over." While it is also true that most jurisdictions require maintenance of patrol cars, including periodic verification of the accuracy of their spedometers, the odds of having inadmissible radar or laser and spedometer evidence are quite small.
It has been documented that the safest speed for driving is ordinarily the average speed of traffic. It may thus be possible to argue that, although you were driving in excess of the speed limit, it would have been dangerous to drive at the actual speed limit. (e..g, the average speed of traffic is 70 mph, and the posted speed limit was 55 mph). Unfortunately, this defense probably will not work. First, it necessarily involves the admission that you were violating the posted speed limt. Second, under such circumstances it is usually the fastest cars on the road which are stopped by the police.
Some states offer defendants in traffic court little to no opportunity to obtain evidence from the prosecutor, other than the citation itself, prior to a hearing on their ticket. Other states offer the ability to demand that the prosecutor produce evidence that it may use in court, with the scope of discovery varying significantly between states. Learn the local rules governing discovery and how it is to be served, and make sure that you make a timely discovery request. When discovery is not available, make the most of the previously described public records laws.
Sometimes the prosecution will fail to comply with discovery, triggering a potential sanction ranging from an adjournment, to the possible exclusion of the non-disclosed evidence from their case, to a possible dismissal. Other times, a review of discovery materials will reveal an avenue of defense to what had previously appeared to be an unbeatable ticket.
If you are stopped for speeding, stating that your bladder is about to burst, that you weren't paying attention to the speed limit (for any reason), or any other excuse that is not a credible account as to why your driving conduct was not necessary to avoid an imminent accident, is not likely to convince an officer not to ticket you, and is not likely to convince a court not to convict you. At most, they may provide a basis for mitigation, where out of sympathy the officer tickets you for, or the court convicts you of, speeding at a lower speed than was recorded. Usually, an officer will write the actual speed that was recorded on the ticket, even when issuing the ticket at a lesser speed, so that the court and prosecutor are aware that you have already received a break.
At the same time, sometimes the outlandish excuse can work - if the officer believes it. For example, a woman I know managed to avoid a ticket by explaining to the officer that she was speeding because she was almost out of gas, and wanted to make it to a gas station before she ran out. She sincerely believed her excuse, and the officer let her off with a warning. A couple of weeks later, while at a restaurant with her family, the officer approached her table with a couple of his fellows and asked that she recite the excuse she had given - apparently, there was some skepticism at the police station as to whether somebody had actually given such an incredible excuse for speeding.