The Fourth Amendment to the United States Constitution requires searches and seizures conducted by the police to be reasonable. Generally, if the police do not have a reasonable suspicion that a driver of a motor vehicle is engaged in criminal wrongdoing, the police may not stop the vehicle. 

However, police may be able, under a sobriety checkpoint program, to conduct brief vehicle stops without reasonable suspicion. Police may conduct such stops to briefly inspect for signs of intoxication, as part of a sobriety checkpoint program. 

Are Random Vehicle Stops Allowed Under the Constitution?

Generally, under the 4th Amendment, people have the right to be secure against unreasonable searches and seizures. In the motor vehicle context, a brief vehicle stop is considered a seizure under the Fourth Amendment, Therefore, the stop must be supported by either reasonable suspicion or probable cause that there is criminal wrongdoing. 

What Can Give the Police Reasonable Suspicion?

The law says that if a police officer has enough cause to briefly detain the driver, then there is enough evidence to create reasonable suspicion of a traffic stop violation or crime. 

Therefore, if the officer reasonably suspects a driver has committed a traffic infraction, then the officer has reasonable suspicion to briefly stop the driver. The officer may then question the driver about the traffic stop violation. The officer may also question the driver about whether the driver is intoxicated, if they have any reasonable suspicion that it could be true. 

A seizure based on reasonable suspicion permits the police to make a brief stop. The police may then briefly hold the driver and any passengers, as long as is reasonably necessary to confirm or disprove the officer’s particular suspicions. If the brief detention and questioning do not provide evidence to justify further detention, then the stop must conclude and the driver (and passengers) must be permitted to go about their business.

Police may not randomly (i.e., at will, whenever they wish to) stop a vehicle if no reasonable suspicion or probable cause exists. This means a stop cannot be conducted solely because an officer wished to do so on a whim. In addition, a mere “hunch” or “guess,” or mere possibility, of criminal wrongdoing, does not suffice to justify a stop.

It is also unlawful for the police to stop a vehicle – say, to obtain the license plate number – simply to confirm the hunch. Reasonable suspicion or probable cause must exist at the time a stop is made.

For example, the police received an unproven, anonymous tip that a young man was present at a bus stop, wearing a plaid shirt, and illegally carrying a firearm. The police, acting on the tip, went to the bus stop, searched the man who fit this description, found the firearm, and arrested him. In this case, the law would consider is an unlawful search and seizure.

The law says that the anonymous tip essentially amounted to a hunch, since the tip did not provide any specific information as to what the man did wrong or that there is a valid reason to search him. In the absence of such specific information, the law would say that there is not enough reasonable suspicion to conduct the search.

Can the Police Conduct a Vehicle Stop Without Reasonable Suspicion?

The police may conduct vehicle stops without reasonable suspicion or probable cause, under very narrow circumstances. The law says that fsuch stops may be conducted may only if special needs (such as the need to protect public safety) beyond ordinary law enforcement needs justify the search or seizure. 

An example of a special need is the need to detect and prevent drunk driving. For example, some states have a sobriety checkpoint program designed to detect and prevent drunk driving. These types of programs are considered lawful under the 4th amendment.

Under the program, all drivers were briefly investigated for intoxication. As such, the search was not random. In addition, searches took a brief period of time to conduct (under 30 seconds). In this case, there are special needs present and that a program permitting driver stop that is not left to the officer’s discretion (i.e., that is not random, and requires all cars to be stopped) does not violate the Fourth Amendment.

It is considered a special need to prevent drunk-driving injuries from death. This special need then outweighed the minimal intrusion on driver privacy, so the seizure does not violate the Fourth Amendment.

These types of examples are based on the 4th amendment which is federal law. While, federal law permits driver stops under such circumstances, state laws do not need to allow such stops. 

Generally, a state, in interpreting its own Constitution, may offer greater protection under its equivalent of the Fourth Amendment, than what the federal amendment provides. Indeed, a number of states have invalidated sobriety checkpoints under state law or a state constitution.

Do I Need a Lawyer If My Vehicle was Stopped and Searched?

If the police have stopped your vehicle and arrested you, then you should contact an experienced criminal defense lawyer as soon as possible. This lawyer can advise you of your rights under the law; seek to have any evidence produced from the stop banned from use at trial; and can represent you in court.