Engine Brakin’ 2: Electric Boogaloo. Or: The City Wants Big Rigs to Turn It Way Down.
This is what it sounds like when a diesel-powered big rig hits the brakes — or, more to the point, the compressed engine brakes that release compressed air stored in the exhaust valves to slow down the vehicle. Got that? No? Try this, then. Or: The Straight Dope! Or maybe…