Driver Aid - road edge & center line finder

When driving it is easy to be blinded by oncoming headlights and lose ability to see the edge of the road. This leads to many cars leaving the road and losing control. I would like a simple alarm that alerts the driver when a sensor realises that the driver is approaching the edge of the road too closely. There must be an easy way to determine the difference between the tarmac road and gravel shoulder or ditch. This could be activated when the headlights are turned on since it wouldn't be required as much in daytime.
Shiela K 02/15/2013
when driving at night and passing other cars glance to the right side of the road taking your eyes off of their lights and still being able to see the edge of the road.