Why Do Cars Have These Features? Test Your Knowledge

To reduce glare and reflections on the windshield — Dark dashboards minimize light reflection off the windshield, which improves visibility and reduces driver distraction and eye strain during daylight driving.

To cushion the door when it reaches full opening — This bumper stops the door panel from swinging too far and hitting the car body, which prevents damage to both the door and adjacent panels.

To indicate the average speed since the last engine restart — The secondary display tracks average speed over a journey, allowing drivers to monitor fuel efficiency and driving consistency without taking their eyes off the road.

To allow the head to break through in a rear-end collision — The gap is intentional—in a rear-end crash, the head must move forward past the rest initially before the rest catches up, reducing whiplash injury.

To protect metal from rust and road salt corrosion — Undercoating protects the vehicle's frame and suspension components from rust caused by road salt, moisture, and environmental contaminants, extending the car's lifespan.

To hold the fuel cap in place when refueling — This tether keeps the fuel cap attached to the door so it won't roll away or get lost, a design requirement adopted industry-wide in the 1990s.

To align with the vehicle's actual pivot point during turns — Signals are placed near the widest part of the vehicle because that's where the rear overhang extends furthest during a turn, maximizing visibility of the turn direction.

To drain rainwater that seeps into the door frame — This weep hole lets water accumulated inside the door from seals or rain drain safely out, preventing rust and corrosion of internal door components.

To add structural rigidity without adding weight to the frame — This feature, called a character line, acts as a beam that reinforces the vehicle's body structure, allowing manufacturers to use thinner, lighter materials elsewhere.

To reinforce the roof structure and improve crash safety — The center seam or reinforcement beam distributes crash forces evenly across the roof and improves rigidity without adding significant weight to the vehicle.

To protect the mirrors from damage in tight parking spaces — Folding mirrors prevent accidental damage when parking in narrow spaces or tight garages, saving costly repairs and maintaining safety by protecting the mirror glass and motors.