Vehicle headlights use concave mirrors. These mirrors are curved inward and have a reflective surface that converges light. When a light bulb is placed at the focal point of a concave mirror, the reflected rays travel outwards as a strong, parallel beam of light, providing excellent illumination for driving at night.

The focal point is a key property: $f=\frac{R}{2}$, where $f$ is the focal length and $R$ is the radius of curvature.

Final answer: Concave mirrors