Can we address the important issue of how to pass someone on the interstate? It surprises me how people don't understand the physics involved.
They work like this: (This is kind of a dirty explanation but meh) When you approach a vehicle from behind the first thing that happens is as you get close the leading vehicle (henceforth referred to as John Cleese) you begin to create drag on it and John Cleese's engine has to work harder to compensate. Then when you swing out to pass, John Cleese is no longer experiencing the drag created by your vehicle (Eric Idle from here on) and Eric Idle experiences a loss in power due to the engine suddenly having to pull the full weight of Eric Idle again. As you overtake John Cleese, Cleese's engine and Eric Idle's engines begin working in tandem with each other to pull the weight of both vehicles. As Idle draws even with Cleese its Cleese's engines that take most of the drag from both vehicles and Idle's engine is not working as hard to maintain the same speed. This causes both vehicles to achieve an almost equilibrium of speed. At this point Idle's engine is not working as hard as Cleese's and eventually it will overtake Cleese enough to suddenly cause Idle to take the majority of the work, easing the burden on Cleese's engine and causing it to maintain an almost equilibrium with Idle's. This can continue back and forth until one vehicle applies enough force to pull far enough ahead that both engines return to only pulling their own weight. In other words, you can't pass someone without having to accelerate beyond them! Just be careful because if you pull back into the same lane as them without a good leading distance you will begin to drag them and they will catch up.