What is overdriving your headlights?

the speed you are travelling in a vehicle is faster than your headlights are allowing you to see in front of you.

If your headlights were very dim and you could only see a very short distance ahead it would be very easy to overdrive your lights.

Or like running as fast as you can, in the pitch dark, in a place you've never been before, with a flash light that is so dim you can barely see 12 inches ahead