Everyone knows that the red, eight-sided stop signs mean you have stop — that is, your car has to come to a complete halt before proceeding or making a turn.

But far fewer seem to understand how the stop sign on the side of a yellow school bus is supposed to work.

For those people, here's an easy primer: You have to stop.

And stay stopped.

The only exceptions are when a physical barrier divides a highway or when a bus is parked next to a school — and even then, you're supposed to slow to a crawl.

In the video above, we see an example of what not to do. A commuter's dashcam captured what happened when a school bus pulled over to discharge passengers on Hamilton Boulevard in South Plainfield. As the bus approaches its stop, it flashes its yellow lights and pulls out its stop sign from the driver's side. The traffic in the two lanes behind the bus stop and wait. But on the oncoming traffic side, six vehicles — including a tanker truck — barrel past.

State law requires vehicles stop at least 25 feet from the bus, even if you're on the opposite side of the road or there's a passing lane. Vehicles have to remain stopped until all passengers have gotten off or on.

On a divided roadway, vehicles on the opposite side don't have to stop but they have to slow down to 10 mph.

If the bus is parked on the same side of the street as a school, cars on either side of the road can pass at 10 mph.

The fines and penalties for violating this law are stiff. A first offense could cost you $100, five points on your license and up to 15 days of jail or community service. After that, the fine increases to $250.

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