What is the main purpose of rear-view mirrors?

The primary function of rear-view mirrors is to provide a clear line of sight to the area behind the vehicle, allowing drivers to monitor traffic conditions and vehicles approaching from the rear. This visibility is crucial for safe driving, as it helps a driver make informed decisions regarding lane changes, merges, and overall situational awareness while on the road. By being able to see what is happening behind the car, drivers can react appropriately to any changes in traffic patterns, ensuring they maintain safety for themselves and others.

The other options relate to useful functions of driving but do not capture the main purpose of rear-view mirrors. For instance, checking for blind spots typically relies on side mirrors and shoulder checks rather than the rear-view mirror itself. Seeing the rear seats is not a priority when driving, as the driver’s focus should remain on the road ahead and the traffic around them. Additionally, while a rear-view mirror can assist with parking by providing some context of what's behind, it is not exclusively designed for that purpose; specialized mirrors or cameras might serve better for that specific function.