Which of the following is a reason for impounding a vehicle?

Impounding a vehicle is justified when it presents a traffic hazard. This reason highlights public safety as a primary concern for law enforcement. If a vehicle is left unattended in a manner that obstructs traffic, creates safety risks, or poses an imminent danger to other road users, law enforcement officials have the authority to impound the vehicle to alleviate that hazard and restore safe traffic flow.

In contrast, reasons such as expired registration, unpaid parking tickets, or a request from the vehicle's owner do not necessarily indicate an immediate threat to public safety. While expired registration or unpaid tickets can lead to legal actions and fines, they do not constitute urgent reasons for impoundment in the same way a vehicle representing a traffic hazard does. Similarly, an owner's request may lead to other actions, such as towing, but it does not align with the primary rationale for impounding due to public safety concerns. Therefore, the reason of a traffic hazard stands as the most compelling justification for vehicle impoundment in this context.