All 50 states regulate how fast motorists can drive on state roadways. Speeding laws vary by jurisdiction, and many states have several types of speed limits. However, in general, excessive-speed laws fall into one of three categories:
What the government has to prove to get a conviction and the available defenses depend on the type of speed-limit you're accused of breaking.
There's not much to explain with absolute speed limit laws. When you drive faster than the posted limit, police can get you for speeding.
Most states have at least some absolute speed limits. For instance, in California, the absolute limit (called the "maximum speed limit") is 65 miles per hour on most highways. And in New York, all the set speed limits are absolute.
Prima facie speed limits aren't as straightforward as absolute speeding laws. When you drive faster than a prima facie limit, it doesn't automatically mean you broke the law. Exceeding a prima facie limit creates only a presumption that you were speeding—you still have the opportunity to prove in court that your speed was safe. If you're able to do so, the judge (or jury) is supposed to find you not guilty.
With basic speed laws, the only issue is whether you were driving a safe speed—generally, no presumptions are involved. In Georgia, for instance, it's illegal to drive at "a speed greater than is reasonable and prudent under the conditions and having regard for the actual and potential hazards then existing."
What constitutes a safe speed depends on the circumstances. But a judge or jury deciding a case might consider factors such as:
Generally, your chances of convincing a judge or jury that you were going a safe speed are better when weather and road conditions were good and you weren't going that fast.
Speeding laws vary by state. So if you get a speeding ticket and have questions or think you might want to fight it, it's a good idea to talk to a local traffic attorney. A qualified traffic attorney should be able to explain the law in your state and whether you have any available defenses.