I'm having a similar problem with various parts of my game.
If my car is over say grass, or going around a corner - I'm using 'set layout zoom' or 'set speed too (while key is pressed).
but this is setting the change permanently. How can I for example say while my car is overlapping sprite x, increase the speed until not overlapping. The same goes for while a key is pressed increase the drift until it is not pressed anymore.
Hope that makes some kind of sense :)