Traffic stops happen on a daily basis. While on your way to work, you may have seen multiple vehicles stopped on the side of the road with a police officer leaning in the window to talk to the driver. You may have even been stopped on one or more occasion due to driving over the speed limit or having a tail light out.
In the movies and on television, the "bad guy" isn't necessarily under arrest until the cop slaps on the handcuffs. That makes for great cinema, but are handcuffs the hallmark of an arrest in real life? Not necessarily.