Final answer:
Mirrors should be adjusted before driving to optimize visibility and minimize blind spots. A parabolic mirror throws more light on the highway as it makes the light rays parallel after reflection, providing better illumination for driving.
Step-by-step explanation:
Mirrors should be adjusted before driving to ensure the motorist's view to the sides and rear of the vehicle is maximized with the goal of minimizing blind spots. This proactive measure is essential for safety and allows the driver to have the best possible situational awareness while operating the vehicle.
In regards to the question about car headlights, using a parabolic mirror in car headlights throws much more light on the highway than a flat mirror because the rays become parallel after reflection. This design causes the light to be focused in a specific direction, which increases the intensity of the light beam on the road ahead, enhancing visibility for the driver without dispersing light in non-useful directions.