In most states, a speeding violation is a criminal offense. The prosecution must prove a driver's guilt beyond a reasonable doubt. However, in some states, the burden of proof for speeding is clear and convincing evidence. It is important that you understand the speed laws in your area and what the state must meet in order to obtain a conviction against you.
Speeding is categorized as a strict liability offense. You can violate the law without being at fault or careless. The State doesn't have to prove that you intended to speed. Simply be exceeding the speed limit, they can find that you have broken the law and should be punished unless you can offer a valid defense against the charge.
All 50 states have either "presumed" or "absolute" speed limits. There are considerable differences between the two and understanding the charge against you will help you to formulate a defense.
When a driver is charged with exceeding a posted speed limit in an area where the limit is "absolute", the law is simple. If you so much as exceed the posted speed limit by one mph, you are guilty of speeding.
Being charged with violating a presumed speed limit means that you were traveling at an unsafe speed. In states that have presumed speed limits, a driver is presumed to break the law by going above the posted speed limit. The burden of proof is the responsibility of the driver to show that he or she was traveling at a safe speed for current road and traffic conditions. Defendants can claim that even if they were exceeding the speed limit, they were driving safely under the specific road, weather and traffic conditions at the time.
Basic speed laws state that no person shall drive a vehicle at a speed greater than is reasonable or prudent and in no event at a speed that endangers the safety of persons or property. However, you can be ticketed for traveling under the speed limit if at the time it was unsafe to do so. Traveling at unsafe speeds, no matter what the speed limit say can result in a citation.