Moving on from earlier discussions about advanced driving and cornering (just click on the links below for the ones that interest you), let's get into a bit more detail with cornering lines.
As mentioned in the slow-in, fast-out story, there are four stages to cornering. These are the approach (positioning ourselves to the outside of the track before a corner), the entry (turn-in), the apex (the furthest point reached towards the inside of the corner during our cornering arc), and the exit.
That slow-in, fast-out mantra mostly applies to the last corner before a straight though. There are loads of other combinations of twists and turns that require a much more nuanced and individual approach to eke out the best lap times possible.
One way to think about this is that the exit of one corner can majorly overlap with the approach to another. But that's not all.
Sometimes, what can look like one long corner is actually quicker to take as two, also known as the double apex. Turn 2 at Sydney Motorsport Park is one of these. Even by yourself, you turn in early and your first shallow apex is 20-30km/h faster than your minimum corner speed. You then sort-of deliberately run wide mid-corner, still taking off speed, so that apex number two uses the benefit of the slow-in fast-out, late-apex method.
Sometimes there can be a few turns in the same direction strung into one multi-apex sweeper. Turn 8 at Istanbul Park Circuit is one example, and the reason it was simply named Turn 8 (instead of turns 8 to 11).
There are sweepers with a tightening radius that you go into fast and continue slowing through them. Some sweepers have a widening radius taken more like the normal slow-in fast-out method, but the apex doesn't seem late because the gentle exit curve makes it look like the car is still in a corner.
Esses and chicanes vary greatly in shape and width, and there can be some awkward long combinations like at Circuit of the Americas in Austin, Texas, or fast ones like the Eau Rouge and Raidillon combination at Spa Francorchamps in Belgium. In both cases you do still aim for wide entries and late apexes for each direction change, but COTA also requires the speed to more noticeably change with every direction change.
Kinks that could be flat out otherwise may be inconveniently placed at the start of a braking zone for a tighter section. Turn 1 at Wakefield Park for example. Some drivers have to back off just a tad earlier than they'd like so as to prevent a load transfer-induced lock-up or spin (depending on the vehicle, and sometimes the brake bias settings).
There can be sharp elevation changes that affect what line you should take (or just whether you can see the exit at all). Mount Panorama, Laguna Seca, Nurburgring Nordschleife, Mid-Ohio Sports Car Course and many others have examples of this.
Bumps on street circuits ruin the theoretical line. Just watch an Indycar race on one.
This highlights the benefit of getting a good local race instructor to teach you the nuances of a particular track, but you can apply a few simple principles yourself.
Prioritise the exit of a section. You want to get back to accelerating again as early as possible for a straighter section.
Learn how far into a corner or section you can continue slowing to reach the minimum speed required, and at the spot it's required for the sharpest turning you need to do. Sometimes you can go in a bit faster than you think and still get the car slowed, turned, and fired out the other side for a good exit.
First though, have a good hard look at the track from above (whether it's a clear photo, or just an accurate map showing the angles and curves). Fast corners can look slow from the ground. Note the actual radius of each twist and turn and whether they tighten or widen, and what they lead to next.
If the opportunity presents itself, also do a track walk, and/or a slow familiarisation lap.
Pay attention to the elevation, the tilt of the road, the bumps and the surface. Rally competitors plan ahead and create pace notes for a reason, but most race circuits should be short enough that you can learn and remember these features for the next laps.
Sam Hollier is an ACM journalist and a motoring fanatic who builds cars in his shed in his spare time.