The 50 states basically use three types of speed limits, called "absolute," "presumed" and "basic." Because each type of speed limit violation often requires a unique defense, it is key to understand which you are charged with violating.
"Absolute" Speed Limits
Most states have an "absolute" speed law. There is no trick to how this works: if the sign says 40 mph and you drive 41 mph or more, you have violated the law. There are not many defenses available, but some include:
"Presumed" Speed Limits
Being charged with violating a "presumed" speed limit means you are accused of driving at an unsafe speed, considering the conditions at the time you were ticketed. But most cops don't look at it this way. They reason that if you are over the posted limit, you are a law-breaker. That's why you really do have a good chance of prevailing if you can show you were just slightly over the limit and road, weather and traffic conditions were good.
But be aware that the "presumed" speed-limit law works both ways. On a pleasant summer morning on a wide, uncrowded highway, it may be safe to drive above the posted speed limit. However, on a wet day when visibility is limited by fog, it may not even be safe to drive at the posted speed limit. In short, an officer can still ticket you for driving at or below the posted limit, if it is unsafe to do so. This is true in all states.
If you're accused of violating a "presumed" speed limit, you have two
Occasionally an officer will incorrectly measure your speed. But even if he does, it can be hard to convince a judge to accept your version of what happened. In short, if you were ticketed in a "presumed" speed area, it is most sensible to rely on the argument that you may have been driving slightly over the posted speed limit, but it was safe to do so considering all the highway conditions at the time. For example, if you know you were driving 33-35 mph in a 25-mph zone, and the officer can probably prove it, you should concentrate your defense on showing that you were driving at a reasonable speed, considering the conditions at the time you were stopped.
Mounting a defense to a speeding ticket in a "presumed" speeding area is not like a typical criminal defense, where the prosecution must prove you committed an illegal act beyond a reasonable doubt. In a "presumed" speed law defense, you have the burden of proving your speed was safe and prudent. In other words, the speed law presumes the posted speed limit is the fastest safe speed. It is up to you to prove that going faster at the time you were ticketed is also safe.
EXAMPLE: Bill was clocked by radar driving 43 mph on a street where 35-mph signs were properly posted. The law of his state contains a presumption that the posted speed limit is reasonable or prudent. To fight this ticket based on a claim that it was prudent to drive 43 mph, Bill will have to overcome the presumption that 35-mph was the only safe speed at the time he was ticketed. He might do this by showing there was no traffic at the time he was stopped and that weather was clear and dry.No question, proving that your speed was safe becomes more difficult the more your speed exceeds the posted limit. Convincing a judge it was reasonable and prudent to go 38 mph in a 35-mph zone may not be too hard. (This helps explain why police officers rarely write tickets for speeding less than 5 mph over the speed limit.) But proving that it was safe to go 65 mph in a 35-mph zone will be close to impossible.
But there are many wide, straight roads designed for safe driving at 35 to 50 mph that have lower posted speed limits because of political pressure on public officials to crack down on speeding. Your testimony, backed by photographs, could show that your speed was safe on these broad, straight roads, even though you were driving faster than the posted limit. If you have weather, visibility and traffic factors in your favor, a judge might find you not guilty, even if you technically violated a "presumed" speed limit.
Here are important ways to build your case:
The "Basic" Speed Law
"Absolute" speed states set an upper limit, above which your speed is considered illegal. Drive one mile over the limit and you are a law breaker. But these states also have a way to ticket you when you are driving under the speed limit if the cop concludes your speed was unsafe. Called the "Basic" Speed Law, it prohibits driving at an unsafe speed, even if that speed is below the posted limit.
"Presumed" speed limit states also have the same law, although it is usually written into the "presumed" law. Or put another way, since the posted speed limit is only presumed to be safe when road or traffic conditions are good, the presumption can be rebutted by the police officer and the safe speed can be much lower.
Technicalities aside, in all states, tickets for driving under the speed limit, but too fast to be safe, are often referred to as "driving too fast for conditions." For example, driving exactly at the 65-mph posted limit on the freeway would be really dumb amidst slower and heavy traffic, in a dense fog, or in a driving rainstorm or blizzard. In commonsense terms, such unsafe driving is unlawful, regardless of higher speed limits. Police most often rely on the "Basic" Speed Law after an accident. They reason that you were driving too fast, no matter how slow you were driving, because you were in an accident.
The difference between fighting one of these tickets and a speeding ticket for going over the speed limit is that here the prosecution has the burden of proving you were driving unsafely. (Again, that's because the posted speed limit is presumed to be safe.) This means the officer must testify that given the unusual road, weather or traffic conditions, your below-the-limit speed was unsafe. This can be tough to do unless you were involved in an accident, since the cop may be hard put to come up with enough hard evidence to rebut the presumption established by the posted limit. If you were in an accident, the officer will probably try to show that it was evidence you were driving at an unsafe speed, and if your speed had been lower, you would have avoided the accident.
However, you do not have to despair even if you were in an accident and are charged with violating the "basic" law for driving at an unsafe below-the-limit speed. The fact that you've had an accident is not absolute proof that you were driving unsafely. Accidents, after all, are not always caused by your violating the law. Often they are caused when another driver screwed up.
If the police officer argues that the accident itself is evidence that
you were driving at an unsafe speed, even though you were not technically
speeding, you must be prepared to challenge him. Your best bets are normally
to claim, and hopefully prove, that the accident could have occurred for
a number of reasons. For example, it could have been: