Most vehicles now have a protective, transparent, plastic lens covering the headlights.
These lenses protect expensive lamps from flying stones and road debris but they discolor over time.
Becoming opaque and cloudy, these lens can severely restrict the amount of light reaching the road.
This clouding is caused by accumulated exposure to ultraviolet light.
This discoloration can become noticeable in as little as 2 years.
The headlamp lens are replaceable only with an assembly, some of them costing in excess of $600.00 retail.