Trucks carry stuff. And tow stuff. So as part of our Truck of the Year testing, we look at how well each of the contenders does the job it's designed to do. Payload and towing capacity are the key numbers truck guys talk about, but they don't tell the whole story: If you divide the payload capacity by the curb weight, for example, you get an idea of a truck's work efficiency. All other things being equal (engine, transmission, etc.), a lighter truck that can carry a larger payload or tow a bigger trailer means you'll likely use less gas when you're not working it. But you can't argue with the laws of physics: Load carrying and towing also affect acceleration and braking performance. By measuring the differences between loaded and unloaded performance, we can see which trucks demand the fewest compromises.