When a place or establishment that you are at has reached it's Mexican population limit.
Phil: A mexican just walked in
Steve: Oh damn, we are at mexican capacity
Ratio used to describe the capacity of a car inhabited by mexicans. Expressed as N=normal capacity of a car multiplied by the mexican capacity ratio of 3. Sometimes this ratio can be exceeded, but it is a good average of the number of mexicans that can cram themselves into a normal car.
A ford taurus has a normal capacity of 4 persons. What is it's mexican capacity?
Answer: 4*3= 12 mexicans