Auto News 5

A single-mode hybrid system is sufficient for small high-mileage cars but, when you're dealing with husky, fuel-slurping trucks, you need more. What we now know as GM's two-mode hybrid system was originally developed for urban buses that began service in 2003. As the technology trickled down to Chevrolet and GMC SUVs, pickups, and (future) crossovers, GM resisted the urge to coin a new name even though the actual number of driving modes increased as the hardware evolved.