large button under gas pedal. Purpose???

On my '88 528e, directly under the gas pedal is a fairly large button that is depressed by putting the "pedal to the metal". Anyone know what this button does, or is supposed to do??? (maybe for check engine codes???)
Thanks

Down shifts your car so you accecelerate faster. Every car made has one.

Thanks Anti... So much is controlled by electronic components. Im used to hearing "kick down lever".

Yes, depressing the gas pedal onto the button causes a "kick-down" condition, in which the automatic transmission immediately downshifts into the lowest gear available at current road speed, and holds that gear until redline is reached.

My Acura Legend was also an automatic, but did NOT have this feature. Neither does my parents' Saturn, which is a manual. However, my parents' 1987 Audi 5000S Wagon did have a kickdown button.

I would imagine this idea was contrived by and is primarily used by German car companies, who have historically been a little more concerned with safety (especially accident-avoidance) than their Japanese and American counterparts.

The idea is to provide the driver with the ability to move his or her vehicle and its occupants OUT of a dangerous situation as rapidly as possible.