There used to be one of those overwritten, never-ending American chain-emails warning about this. The idea is that if an old tech rear wheel drive American car with the speedo drive on the front wheels loses traction at the rear, the lost speed recorded by the speedo drive will tell the engine to increase revs and the rear of the car will go out of control. These days, the speedo drive of a front wheel drive car is in the final drive, so that simply can't happen. And on rear drive cars such as most BMWs, if the car's ABS/ESP system detects a lack of traction, it automatically disengages cruise control.