What you’re looking at is not a secret code, but a set of pacenotes. Hidden in those letters, numbers and squiggles is all the information double Intercontinental Rally Challenge champion Andreas Mikkelsen needs to tackle some of the world’s most demanding roads as quickly as possible. In the dark, if needs be. Or on slick tyres in the wet. Or even, on occasion, in fog so thick he can’t see the end of his car.

“Our system is the work of years of honing what we do,” says Mikkelsen. “Every driver has their own way of making pacenotes, and we’ve settled on around 30 different sayings that tell me exactly what I need to do. There’s enough information in there for me to drive flat out, but not so much that I get overloaded.”

Those notes are delivered to Mikkelsen by his co-driver, Ola Fløene, a veteran of WRC, IRC and the Dakar Rally who has been a guiding influence for all of his sidekick’s career. Together they have spent the past seven years perfecting the system of calls that have won their two titles.

“We are always looking for ways to improve our performance, and getting the notes right is perhaps the most important,” says Fløene. “Even if we are flat out mid-stage and we think there is a chance a note could have been better, I will make a quick mark in pencil to amend it for next time. Sure, we’re going fast and there’s another call to make, but with experience it’s amazing what you can do.”

Today, Mikkelsen and Fløene’s notes are made up in three different languages: Norwegian, Swedish and English. Why? “Andreas is fluent in them all, so we pick the language that has the shortest way of describing what we want to say,” says Fløene. “When you are trying to describe two or three tricky corners in as much detail as possible while you’re flat in sixth gear, it really helps to be as brief as possible.”

Providing enough detail without delivering so much that it’s confusing is tricky, and is relative to the sharpness of the driver’s brain. Mikkelsen, for instance, has six different corner descriptions: ‘ok’, ‘maybe plus’, ‘maybe minus’, ‘fast’, ‘fast fast’ and ‘flat’. For each, he’ll fractionally modify his approach to a corner. Then there’s the instructions for how much to cut apices; ‘no cut’ warns to keep all four wheels on the road, ‘cut’ means he’s okay to put one wheel to the inside, ‘max’ means he can put all four wheels off the road and ‘super cut’ is a rare shout that means a massive time-saving detour.

The level of detail is astounding, until you appreciate the sort of speeds at which rally crews are driving and the types of roads they are on. “Rallying has many challenges,” says Mikkelsen. “Blind corners are normal, and so are crests. If Ola tells me the road afterwards is straight, I will trust him and commit. If you lift a fraction in this championship, or run a fraction wide and go off line, you will not set a fastest time. The competition is that intense. You have to get your pacenotes perfect and then drive to them in exactly the way they describe.”

Because Mikkelsen sits so low in the car (to help with the centre of gravity), he often can’t see over crests in the road. “The fact is, I am not driving primarily with my eyes but with my ears,” he says. “My pacenotes are my instructions, and they build a picture for me of what I need to do.”

On each event, Mikkelsen and Fløene get a chance to recce each stage twice in a road car, at road-legal speeds. If they’ve done the stage before, they are allowed to modify the set of notes they have. If not, they must start from scratch. The world’s leading rally drivers are closely monitored to ensure they aren’t getting in sneaky extra practice outside the event timetables. The only concession is that they’re allowed to video the recce. They usually watch a stage back between two and six times, depending on its complexity, checking their notes. But after that it’s on to the rally and trusting every bit of information as they battle over tenths of a second.

“That’s part of the reason rally drivers can’t just arrive at the top level and expect success,” says Mikkelsen. “They must hone their experience of the stages and get the notes spot on. That’s hard to do from two slow-speed runs – the first of which is normally done very slowly, so that there’s time for me to make a judgement and Ola to write it down. And of course different types of cars need different notes, depending on their capabilities.”

So what happens when the fog descends and visibility is near zero? In any form of racing – on a prescribed circuit the competitors can memorise, remember – they’d go home. In rallying, it’s a case of driving according to the conditions. “I just make sure I deliver the notes precisely,” says Fløene. “If we’ve got the notes accurate from the recce, Andreas just drives to what I say. On the straights I can help a little more by counting down the distances using the trip meter, but otherwise we just carry on. Of course, the times are a lot slower – but, trust me, it doesn’t feel that slow when your driver pulls top gear and you know he can’t see where he’s going.”