CHICAGO (NewsNation) — This week, NewsNation has been focusing on the lifeblood of the American economy: truckers.

NewsNation’s Nick Smith took viewers inside the engine of a semi-truck from XPO Logistics. The 18-wheeler has an engine designed to travel 1 million miles before an overhaul. The engines are six times larger than a car’s size and weight. Also, weight-wise, these engines are designed to run nonstop.

The 18-wheelers get about eight miles per gallon, not only because of the size of the cargo and everything that they carry but because of the sheer weight.

Due to that weight, it’s also important for drivers to slow down when these trucks are near because of how long it takes these trucks to stop. Sometimes these trucks need the length of two football fields for a semi that is fully loaded with cargo to stop.

Meanwhile, 40% of trucks on the roads no longer have citizens band radios, also known as CB radios, because of cellphone technology and other advancements, but there are a few radio terms truck drivers still use.

For instance, an “alligator” is when someone has a blown tire on the highway. A “big slab” means you’re heading out on the highway, and a “black eye” lets another trucker know that they have a headlight out.

Truck drivers also use group chats to keep each other awake on the roads and let others know about any potential hazards as they’re driving and navigating the roadways.