Under what condition can an officer impound a car after arresting a person in it?

An officer can impound a car after arresting a person in it if the vehicle cannot be safely left at the scene. This condition ensures that public safety is maintained; if a vehicle poses a risk of obstruction, hazard, or is likely to be vandalized or stolen, it is within the officer's authority to impound the vehicle.

This rationale is grounded in the principles of maintaining order and safety on the roadways, as well as preventing potential legal issues that could arise from leaving a vehicle unattended in a dangerous situation. For instance, a car left in a high-traffic area or a location that impedes other vehicles can create significant hazards.

Other conditions, such as whether the owner requests impoundment or whether the officer deems it necessary without justifiable cause, do not provide the same level of safety assurance that is mandated by law. Additionally, although blocking traffic can be a factor, it is not a standalone reason for impoundment compared to the broader safety considerations outlined in the correct answer.