One of the oldest lessons in the book is also among the most important: When following another vehicle in traffic, always remain at least three seconds behind them. That’s the 3-Second Rule, and it’s a rule that could save a life.

Ask anyone. Ask the driving instructor, the school bus driver, or the trucker with hundreds of thousands of miles under his belt. They would all vote this old-but-great rule of thumb among the best pieces of advice. Here’s why:

One… It’s simple.

Without having to do any exact calculations, this old rule is easily adaptable to real world variations. Bad weather? Extend the following distance by a second or two. Heavy traffic, icy roads, distracted drivers, tailgaters… you name it, we say add a second or two to it.

Two… It works.

Drivers that follow the 3-second rule will eventually witness a traffic accident, a crash, or even just a close call. More often than not, they will have enough time to avoid that incident, escaping with nothing but a memory of what might have happened.

Three… It saves lives.

In your driving future, there will be countless times when maintaining a safe following distance saves your life, your passenger’s life, and/or the lives of drivers all around you.

There are plenty more reasons to remember this simple rule – it saves gas. It saves repair costs. It lowers insurance rates. It makes the roads safer. It improves traffic flow – but let’s keep it simple and stick with that magic number. The number 3.