# Line Theory: The Perfect Corner 1 & 2

In The Perfect Corner 1 and 2, Adam Brouillard has made the most important contribution to racing line theory since the first technical book on the subject, Taruffi’s 1959 The Technique of Motor Racing.

A few months ago I started reading, studying and applying knowledge gained from these two books. They are an exposition of line theory, the theory of what driving lines are most efficient, i.e. the fastest, around a race track. Brouillard takes a physics-based approach.

With The Perfect Corner 1 and 2 we can look at all the various permutations of line theory since 1959 and clearly understand what is right about each one and why and what is wrong about each one and why. When a new theory explains all the previous ones, that makes for a powerful theory.

Brouillard teaches that there are only three types of corners in all of road racing and autocross. (He tells me he began as an autocrosser.) The three are the standard corner, the chicane and the double-apex. That’s it.

A standard corner has enough space before and after to stand alone so that the entry and exit can be optimized without regard to the previous or following element. A chicane is defined as two corners in opposite directions that are so close to each other that they must be optimized together. (The autocrosser’s slalom is two or more chicanes end to end.) A double-apex is two corners in the same direction that are so close to each other they must be optimized together.

The books give rules for how to classify each corner you will encounter and rules for how to determine the most efficient line through each type.

My approach to autocross is now forever changed because of Brouillard. What I’ve realized in doing autocross events this year with his concepts and rules in mind is that many autocross courses are more complicated than most road-race tracks. Some autocross courses essentially have no stand-alone elements. Everything is connected in a series of chicanes and double-apexes with only the rare standard corner. So, applying the methods and rules he gives is not easy. Some of it is immediately applicable, some is not. He tells me he’s thinking of writing an autocross book. I hope he does. Soon!

In the meantime, get these books from his website here and start a new journey into autocross.