What feature must all cars possess according to vehicle regulations?

The requirement for all cars to possess a fire extinguisher is mainly centered around safety regulations. A fire extinguisher acts as a crucial safety measure, providing drivers and passengers with the means to quickly respond to a vehicle fire or other emergencies that could pose a larger threat. This feature enhances the overall safety of the vehicle and occupants, ensuring that in case of an unexpected fire incident, help is readily available to manage the situation effectively.

While other features like airbags are beneficial for passenger safety, not all vehicles necessarily require a specific style of airbag or the infrastructure to support one, as regulations may vary. Similarly, a sunroof and manual transmission are not standard requirements, as they are considered optional features driven by consumer preference and vehicle design rather than regulatory necessity.