Final answer:
A driver must present a valid driver's license, vehicle registration, and proof of insurance in the case of a traffic violation. Demanding proof of citizenship without any violation or crime might contravene the Fourth Amendment. Document checks are routine during traffic stops.
Step-by-step explanation:
In the case of a traffic violation, the documents that must be provided by the driver typically include a valid driver's license, the vehicle's registration card, and proof of insurance. The requirement to show these documents is standard procedure during a traffic stop to identify the driver and confirm that the vehicle is legally registered and insured for operation on public roads.
Regarding the case of Juan Carlos mentioned, if he has not committed any traffic violation or crime, the police's actions in demanding proof of citizenship could be considered unconstitutional. The relevant constitution amendment that would apply here is the Fourth Amendment, which protects individuals against unreasonable searches and seizures and requires any warrant to be judicially sanctioned and supported by probable cause. In any lawful traffic stop or check, though, presenting driver-related documents is a routine expectation.