Red light violations are among the most traffic tickets that drivers receive. Here is basic information about fighting a red light ticket.
Most state laws on stoplights read something like this:
A driver facing a steady circular red signal shall stop at a marked limit line, or if none, before entering the crosswalk on the near side of the intersection or, if none, then before entering the intersection.
The elements of this offense that the government must prove are basically the same as for driving through a stop sign, with one obvious exception—stop signs are constant while traffic lights cycle through from colors from green to yellow to red.
In most states, it's legal to drive through an intersection when the light is green or yellow. Generally, as long as the front of your vehicle entered the intersection (passed the crosswalk or limit line) before the light turned red, you haven't broken the stoplight law. The laws of most also allow drivers to turn right at a red light after making a complete stop.
Unless your red light ticket was issued by an automated camera system—which many states use to catch red-light violators—the government's evidence will typically consist of only the testimony of the officer who issued the ticket. So, stoplight ticket defenses generally focus on casting doubt on the officer's perception of events.
As previously noted, if you cross the limit line prior to the light turning red, you generally haven't broken the law.
The only time an officer has a really good view of when your car entered an intersection is when he or she is sitting directly to the side of, and close to, the intersection. But chances are the cop was someplace else—sitting across the street in a parking lot, perhaps.
You can cross-examine the officer as to exactly where he or she was when he or she says you ran the red light. Ask the officer whether other cars were in a position to obscure the view of the intersection. Then, when it's your turn to testify, provide detailed testimony, making it clear where you were when you saw the light turn yellow and how far you were across the intersection when it turned red. Make a simple diagram like the one below (adapted for your particular situation, of course) and show it to the judge.
When a judgment call is involved (such as the location of your front bumper when a light turned red), two observers are always far better than one. So, if someone who was riding in your front seat can testify that the light was still yellow when you entered the intersection, it can strengthen your defense.
Another defense to a red light ticket focuses on the officer not being able to see the signal that allegedly turned red before you entered the intersection.
When a light turns green, we assume the light for cross-traffic has simultaneously turned red. For example, if an officer approaches an intersection with a green light and sees you drive across the intersection, the officer will assume you ran a red light and won't later check to be sure that the light changes were synchronized. Sometimes they aren't. If you can go back to the scene and document that the light was mistimed, you should be entitled to acquittal. Don't dismiss this possibility—neither machines nor the people who time them are infallible.