Amid the roar of the engines, the screech of the tires and the cacophony of the crowd, they diligently and silently go about their work.
In a sport where safety is paramount, if it wasn't for them the Formula One circus would come to an abrupt halt.
"I don't like the word heroes," Pete Berry, the man in charge of the marshals who will line the track at this weekend's British Grand Prix, told CNN.
"But when marshals give of their time freely to make motorsport successful, to make sure it's safe for the drivers, the last thing on your mind is that you may be seriously injured -- or you may not go home."
The role of these volunteer men and women has been put sharply into the focus by the recent death of marshal Mark Robinson, who was killed after falling under a crane in the immediate aftermath of the last race in Canada.
Marshaling is a dangerous hobby and feelings among its global community are still raw after the tragedy in Montreal.
"For one of our own to be involved in a fatal accident is truly shocking," explained Berry, who has been on duty at every British round of the F1 world championship since 1981.
"Any incident like that, wherever it is in the world, is something we feel personally.
"At the first race meeting that took place at the Silverstone circuit the week after Canada, many of the marshals came in and wanted to do something as a mark of respect.
"We observed a minute's silence trackside as a sign of unity in memory of our colleague. We all felt it very strongly."
There will be close to 1200 men and women volunteer marshals at Silverstone, the legendary circuit in the heart of England that is the home of the British Grand Prix and which staged the first-ever F1 world championship race in 1950.
Despite the reverberations of the accident in Canada, Berry says it will be business as usual for the marshals as they ensure the world's fastest cars and drivers race safely.
"I don't think there is anything procedurally we are going to change," said Berry. "We will be extra aware -- but at the end of the day what we do is dangerous.
"Racing drivers understand the consequences of what they're doing and so do marshals."
There is, of course, one obvious difference between those in the cockpit and those waving flags to communicate messages to the drivers, working in the hum of the pit lane, or waiting trackside for a gap in the traffic before leaping across the barriers to remove a dangerous piece of debris from the circuit -- money.
While Mercedes driver Lewis Hamilton is F1's highest earner, reputedly commanding an annual salary of $31m with Ferrari's Fernando Alonso taking home $26m, the marshals are unpaid for the work that they do.
They do not even receive expenses for spending a long weekend away from home. Instead the British race organizers give them one free guest pass, a commemorative baseball cap, free on-site camping and a voucher towards lunch.
The marshals -- many of them fresh from their day jobs -- arrive for "work" at the British GP at 6am and are on duty for the next 13 hours.
Despite the time and expense involved -- not to mention the danger -- Berry argues that if marshals were paid their sense of responsibility would diminish.
"There is no room for people who are there for the money and who don't give a damn," he explained.
"When someone steps out from the barriers they are at risk and you want people who are protecting each other's back, who understand the job and who aren't scared of the equipment.
"People who turn up for money are not going to be the people you can trust your life with."
Marshaling may not be for everyone but for those working in Britain, and at the other 18 grands prix around the world this season, the rewards would seem to outweigh the costs.
"You get very close to the sport, that's one of the things I love about it," explained Peter Greenlagh, standing, unruffled by the brisk, British breeze, at the famous sweeping curves of Maggotts and Becketts at Silverstone.
"You're not just close to the cars, you're involved with them and you're making sure these drivers carry on driving safely.