[mylifeandtimes]

In other words, 15% of people are ALWAYS speeding, by definition.

So with perfect enforcement (punish everyone over the threshold), how do you enable an 85th percentile rule?

[criddell]

> 15% of people are ALWAYS speeding, by definition

Not necessarily. If the data is heavily clustered around a single value, the percentile collapses to that number.