When a race needs to be neutralised due to weather, incident or debris, the official Formula One Safety Car - the Mercedes AMG GT R - is dispatched to lead the field.
Behind the wheel is Bernd Mayländer, who has led the field for over 700 laps since taking on the role in 2000 - a tally which would put him in the top 30 for most laps led in F1 history, if he were on the grid!
But, after all these years of driving the Safety Car, what's the biggest challenge in his role?
"I need to know where there has been an accident, where in the field I join the track, where the other cars are and if there are any cars that need to overtake me," Bernd explains.
"I also need to know where they can best overtake me without creating a risk to the other cars or the marshals. I'm in constant contact with race control. Every Safety Car is different - but that's what I like about it."
The Mercedes-AMG GT R is new for 2018. How did Bernd familiarise himself with his new set of wheels?
"Over the winter, I had five days in the new car on a high-speed test track in Nardo, Italy," he says. "It didn't take me too long to familiarise myself with it as I drove the GT S before.
"The new car is overall faster, though. It's about one second quicker per kilometre on the race track. The car is equipped with a specific communications and GPS mapping system and the highly visible safety lights. But most of the car - the engine, the gearbox, the suspension - is all standard."
How does the process work for Bernd when the Safety Car is deployed?
"I watch the race live in my car," he explains. "I also have a GPS mapping system installed so I know where all the cars are at any time.
"As soon as there is an incident, I get a radio call from race control, saying 'Safety Car on standby'. At that point, I'm already in gear, ready to start at any second.
"I leave the garage as soon as I get the call 'Deploy Safety Car'. Once the situation is cleared, I get the call 'Safety Car in this lap'.
"Even if I lead the field until the end of the race, I need to come into the pits on the very last lap and unfortunately never get to take the chequered flag."
The Canadian Grand Prix is a race that typically features Safety Cars, due to the close proximity of the walls and changeable weather conditions.
One of the most memorable races in recent years to heavily feature the Safety Car was the marathon 2011 Canadian GP. So what are Bernd's memories of it?
"It was a crazy race," he said. "I lead the race for 46.9 percent of the distance. It turned out to be the longest Grand Prix in Formula One history because the weather conditions were so bad that they had to suspend the race for quite a while.
"In fact, the conditions were so bad that I even had the time to grab a coffee and a bite during the red flag! I had my snack in the race control room, that way I could make sure that I wouldn't miss any important information."
Being the Safety Car driver is a unique and crucial role in F1 and the deployment of the Mercedes-AMG GT R can dramatically change the course of a race.
Few drivers get the chance to lead an F1 race, let alone lead for hundreds of laps. But, there's only one driver able to do so without actually being behind the wheel of an F1 car and that's Bernd.
Want to know more about Safety Cars? From the decrease in pace to the challenges drivers and teams face, find out more here.
And if you're looking for all the techy details about the new Mercedes-AMG GT R Safety Car, click here.