When it's time for a road trip, you know what to do. You pack your books and electronic devices into a bag and jump in the back seat. Before you can pull out of the driveway, though, there's one thing you need to do. What is it? Buckle up, of course!

When you ride in a car or a truck, you always have to wear a seat belt. It's such a common thing to do, you probably don't even think twice about it. And everyone knows why: safety. If you're ever in an automobile accident, seat belts can save your life and minimize injuries.

If you're like most kids around the country, though, there's probably one ride where you don't have to wear a seat belt. Where's that? To school! In fact, the overwhelming majority of school buses across the United States do not have seat belts. Have you ever WONDERed why? Does it seem strange to pack dozens of precious lives into a big yellow tube and send it speeding down the road without any seat belts?

Today, the United States government, through the National Highway Traffic Safety Administration (NHTSA), does not require seat belts on school buses weighing over 10,000 pounds. Federal law does require seat belts on lighter buses, but the seat belt decision for larger buses is left to the states. To date, only six states (California, Florida, Louisiana, New Jersey, New York, and Texas) require seat belts on school buses, and some of those states only require them on newer buses.

Why wouldn't the federal government require school buses to have seat belts? The simple answer is that they don't need them. In a cost/benefit analysis, the cost of adding seat belts to school buses outweighs any potential benefits, according to NHTSA studies.

Modern school buses are large and heavy, and their passengers sit high off the ground. This means they are remarkably safe. Each year, over 400,000 public school buses carry almost 25 million children more than 4 billion miles. Yet, fewer than 10 children die each year in school bus accidents, and studies show that seat belts would not have prevented most of those deaths.

By way of comparison, about 800 children die each year while walking, biking, or riding in a passenger car to or from school. The National Safety Council concluded that school buses are 40 times safer than the average family car, making them the safest of all forms of ground transportation.

School buses are designed to be safe. School bus seats have high backs and lots of cushioning. In addition, they're packed together tightly to achieve compartmentalization. In the event of a crash, the seats absorb most of the impact, protecting the children who sit in them.

Not only would adding seat belts to school buses be costly, experts cannot agree on what type of seat belts should even be used. Because children tend to move around a lot, there's no guarantee they would use seat belts, if installed, or use them properly. Bus drivers certainly cannot be tasked with enforcing proper seat belt use, because their attention must remain focused on the task of driving.

Given that experts believe that adding seat belts to school buses would have very little, if any, impact on safety, most states have concluded that there's simply not enough benefit to justify the cost of adding seat belts to school buses. And the cost to do so is not insignificant. Experts estimate adding seat belts to all school buses could easily cost each state over $100 million.

Experts also fear that adding seat belts to school buses would reduce overall bus capacity. To the extent that fewer children can ride buses, they might be forced to seek other means of getting to and from school — means that have proven to be more dangerous than riding a school bus without seat belts.

Wonder What's Next?

Lights! Camera! Action! Wonderopolis goes behind the lens tomorrow!