An analogous condition exists in an automobile with a manual transmission going down hill or any situation where the driver takes his or her foot off the gas pedal, closing the throttle; the wheels want to drive the engine, possibly at a higher RPM. In a two-stroke engine this can be a catastrophic situation: as many two stroke engines depend on a fuel/oil mixture for lubrication, a shortage of fuel to the engine would result in a shortage of oil in the cylinders, and the pistons would seize after a very short time causing extensive engine damage. Saab used a freewheel system in their two-stroke models for this reason and maintained itmaintained and early Saab 99 for better fuel efficiency.