look up any word, like bukkake:
 
1.
A measure of the number of Dufi currently on the road with you.

On a freeway, the Dufi Index is defined as 100 minus your current average speed. The higher the number, the slower you go.
Man! The Dufi Index is high today! Traffic is congested because of the large number of dufi on the road.
by Joel Corley April 29, 2008