Being pulled over by a police officer is an unsettling event. However, the police cannot detain you without reason. A traffic stop by a law enforcement officer is considered a seizure of the vehicle’s occupants. Due to the constitutional right of persons to be free from unreasonable searches and seizures, law enforcement officers cannot detain the occupants of a vehicle for an “unreasonable” amount of time. The key word is reasonable. The “reasonableness” of the length of the stop will be determined by a judge a couple of months after you have been issued a citation or arrested. Any evidence that was obtained as a result of an unreasonable detention cannot be used against you.
An officer has the authority to pull over a vehicle when he has reasonable suspicion that a crime has occurred and the vehicle or an occupant is somehow connected to it. This can be for a minor traffic infraction such as changing lanes without signaling to something much more serious. More than a hunch or gut-feeling is required to make the stop and the officer has to be able to explain to a judge the reason he stopped the car in detail.
After the reason for the initial stop has been investigated and concluded, the officer should release the vehicle and occupants unless contact with the vehicle has led to a reasonable suspicion of further crime. For example: if an officer stops a car for running a red light and detects the odor of marijuana coming from the vehicle, not only can he issue a citation for running the red light he now has reasonable suspicion to detain the occupants for further investigation into marijuana possession.
If officers feel that they cannot investigate their reasonable suspicion in a safe manner they can wait for backup. There are limitations to this as well and it cannot be used as an excuse to detain a driver for an extended period of time unless they are investigating something beyond a traffic citation. Police officers can order all persons out of the vehicle to ensure the stop remains safe for both the officer and the vehicle occupants.
Generally it is imprudent to confront an officer and get into a discussion of constitutional rights, it will often irritate the officer and spur them into taking a closer look at you and your vehicle. When you get pulled over try to remain calm and be courteous, have your vehicle documents ready to hand over. The officers hold all the cards in this situation and they have wide discretion and make the decision on the spot whether you will get a citation, get arrested, or drive away with a warning. Even if you are getting a citation just take it and go, it is not an admission of guilt and if you think the officer is mistaken, fight it in court.