The Fourth Amendment to the United States Constitution requires that searches and seizures of persons and property be reasonable. And the U.S. Supreme Court has held that a search or seizure is generally unreasonable unless the police officer or other government agent performing the search or seizure can state a basis for individualized suspicion of wrongdoing by the person searched or seized—as opposed to the search or seizure being motivated by a general interest in crime control.

The Supreme Court has recognized limited circumstances in which the usual requirement of individualized suspicion does not apply because the search program is designed to serve special needs beyond the normal need for law enforcement and crime control. On that basis, the Supreme Court has upheld search programs that are not based on individualized suspicion for (1) random drug testing of student athletes; (2) drug testing for United States Customs service employees seeking transfer or promotion to certain positions; and (3) drug and alcohol tests for railway employees involved in train accidents or found to be in violation of specific safety regulations.

The Supreme Court has also allowed searches for government administrative purposes without particularized suspicion of misconduct, when the searches are appropriately limited—including (1) a warrantless inspection of a closely regulated business (an automobile junkyard); (2) a warrantless inspection by city firefighters and the fire chief of fire-damaged business premises to determine the cause of the fire (arson); and (3) a warrantless inspection to ensure compliance with the city housing code. And regarding traffic checkpoint searches and seizures, the Supreme Court has allowed searches and seizures of motorists without individualized suspicion at (1) a fixed Border Patrol checkpoint designed to intercept illegal aliens; (2) a sobriety checkpoint aimed at removing drunk drivers from the road; and (3) a checkpoint or roadblock for the purpose of verifying drivers’ licenses and vehicle registrations.

The Supreme Court has declined to approve traffic checkpoint programs whose primary purpose was to detect evidence of general criminal wrongdoing—such as a random spot check of a motorist’s driver’s license and vehicle registration, or a narcotics checkpoint using a trained narcotics detection dog. The Court held that these programs do not seek to protect society from the same type of immediate, vehicle-bound threat to life and limb as a sobriety checkpoint, for example, and are primarily for general crime control purposes. When law enforcement authorities pursue what are primarily general crime control purposes at traffic checkpoints, stops (searches and seizures) can only be justified by some amount of individualized suspicion.

In Texas, as in all states, the Fourth Amendment's requirement for reasonable searches and seizures is upheld. This means that, generally, law enforcement officers must have individualized suspicion of wrongdoing to conduct searches or seizures. However, the U.S. Supreme Court has recognized exceptions to this rule for certain 'special needs' beyond crime control, such as drug testing of student athletes or certain federal employees, and for administrative searches like inspections of regulated businesses or fire-damaged premises. In Texas, as elsewhere, sobriety checkpoints and Border Patrol checkpoints are permissible without individualized suspicion because they aim to address immediate threats to public safety, such as drunk driving or illegal immigration. However, the Supreme Court has ruled against checkpoints that primarily serve general crime control, such as random checks for narcotics or general criminal wrongdoing, unless there is some level of individualized suspicion. Texas law enforcement must adhere to these principles, ensuring that any deviation from the requirement of individualized suspicion is justified by a recognized exception.