As school starts up again in the Hudson Valley we thought it would be a good idea to clear up one of the most misunderstood school bus laws.

It's happened to us all. You see a school bus ahead with their yellow lights flashing and wonder if you're supposed to stop or keep going. Everyone knows you must legally stop if the red flashing lights are on and the stop sign arm is extended, but what about those mysterious yellow lights?

When you're traveling behind a school bus that begins flashing their lights the answer is very clear; you need to stop. As the yellow lights come on the speed limit is reduced to 20mph, regardless of what the street signs say. So attempting to speed up and pass the bus is an absolute violation of the law.

When approaching from the opposite direction of the bus, the same rules are in place but it may be a little less clear what you should do. If you see the yellow lights you need to slow down to 20mph. This is where you need to use your judgement, and it helps to know the rules that bus drivers follow.

If a bus driver is traveling at 35mph or less the yellow lights will be turned on between 100 and 300 feet before stopping. If traveling faster than 35mph, the bus will start flashing the lights from 300 feet to 500 feet before stopping.

So, unless you're right up on the bus as the lights turn on and stopping your vehicle abruptly would cause you the be rear-ended, you need to slow down and come to a full stop as soon as you see the yellow flashing lights.

While stopping for a bus can inconvenience you for a minute or two, failing to follow the law could lead to the death of a child, or at the very least some very serious penalties. Violators of the law could receive fines from $250 to $400. In addition, an automatic five points get added to your license and you could serve up to 30 days in jail. And that's for first-time offenders. There's no three-strikes rule when it comes to school bus safety.