Wheeling, W.Va. (WTRF)-When you think of a school bus, you probably think yellow and black. But as eye-catching as it is, it’s not by accident.

So why are school buses yellow? Ohio County Schools Head of Mechanics Randy McCardle tells 7News it’s because you can easily see them in dim conditions.

And the black rails, also known as rub rails, aren’t just randomly placed on the sides and back of the bus. They’re markings to tell first responders where the floor line and seat line is, which comes in handy if there’s ever a serious bus crash.

“The first responders, it would give them a good idea if all the damage to the bus is below that first black line, it didn’t impinge on the passenger department. There’s probably just minor injuries.”

Ohio County Schools Head of Mechanics Randy McCardle

Not only that, but McCardle says the black lines also lets first responders know where they may have to cut in for a quick evacuation.  

As children go back to school, he also wants to remind us to watch out for the big yellow buses and the little children.