Final answer:
An unsafe vehicle can be put out of service when it poses a risk to the safety of its occupants and other road users due to known defects or potential hazards.
Step-by-step explanation:
An unsafe vehicle can be put out of service when it poses a risk to the safety of its occupants and other road users. This can occur in several situations, such as when the vehicle has known defects that could lead to accidents or injuries. For example, if a manufacturer is aware that a certain model has brake system defects that can cause brake failure, accidents, injuries, and deaths, it is their responsibility to take that vehicle out of service and address the issue before selling it.
In addition, an unsafe vehicle can be put out of service if it poses a potential fire hazard or extreme physical danger. For instance, if there is uncertainty over whether a serious fire or hazard awaits after an alarm, it would be necessary to take the vehicle out of service to prevent harm.
Overall, the decision to put an unsafe vehicle out of service is based on ensuring the safety of individuals and complying with laws and regulations that prioritize public safety.