In criminal cases a common concern is that the officer requested the driver or other person to exit the vehicle. There is a line of thought that being removed from the vehicle requires a safety concern or other good reason. Some may question what issue(s) exist getting out of the car, others do not like the feeling of being seized, however in the context of criminal cases, exiting from a vehicle often discloses damaging evidence.
Criminal cases, especially those involving firearms are significant and tense starting at the roadside encounter. The recent appellate case of Rose v. State from the First District Court of Appeal, in which the person was convicted of possession of a firearm by a convicted felon, is a scary reminder of how interactions with law enforcement can go horribly wrong, fast. The Defendant was convicted of possession of a firearm by a convicted felon.
In criminal cases, searches resulting from vehicle stops have been hotly litigated since the automobile became available to the public in mass. Since cars are mobile and not as private as your home, the Supreme Court has interpreted the constitution to afford vehicle searches and seizures less protection.