Ebbie, According to the law professor interviewed on NPR, the Courts have ruled that law enforcement can lawfully even if unreasonably order one to get out of the car (or stay in the car) on a traffic stop.   Then, if one does not comply with the order, one can legally be arrested.

She was within her rights to not put out the cigarette, but that pissed the cop off and he turned into a bully of the worst kind.