When driving through torrential rain or snow motorists normally have headlights on, especially at night time sometimes creating a wall of water or snow.
This can reduce visibility even more as light is reflected back at the driver from the rain droplets or snow particles. Enter a new headlight system from US researchers that will illuminate the road around falling droplets of rain.
It does this by calculating the trajectory of the rain from a video camera, digital light projector and beam splitter then switching off lights that are in the path of the droplets – all in 13 milliseconds and with no flicker for the driver or oncoming vehicles.
The system is still in early stages as it has accuracy issues and the lights don’t illuminate as far as normal driving lights.
http://www.wired.com/autopia/2012/07/smart-headlights-dodge-rain/