Formula One was recently reminded of one of its most tragic images: the wreck of a blue and white racing car at the edge of the track in Imola, Italy, on May 1, 1994, and the yellow and green helmet of its driver tilted to the side in the cockpit.

That driver was Ayrton Senna, one of the greatest racers in Formula One history, winner of three world titles, 41 races and 65 pole positions, who had been killed in an accident at the age of 34. A terrible aspect of the tragedy, then known only behind the scenes, was that the man who tended to the injured driver and directed the emergency medical team that tried to save him at the track, was a close friend of Senna’s.

Although the accident is never far from the collective consciousness in the paddock, the Formula One world was reminded of the event after Senna’s friend and doctor, Sid Watkins, died on Sept. 12 at the age of 84. But if Watkins saw his friend die — a day after the death of another driver, the rookie Roland Ratzenberger — the incident would kick-start a crusade by him and the International Automobile Federation to make safety improvements that would help save many drivers’ lives.

Since that black day, thanks in no small part to Watkins’s efforts, no driver has died at a Formula One event or test.

Watkins, in fact, had begun efforts to improve safety long before, starting in 1978, when he was hired by Bernie Ecclestone, then the leader of the Formula One teams’ association and today the series’ promoter, to do whatever he could to reduce the number of deaths and serious injury.

That earlier effort had also been instigated after the death of a driver, Ronnie Peterson, who died because of insufficient medical facilities after an accident at the Italian Grand Prix at Monza in 1978. Watkins had been hired earlier that year, but after he was stopped by police at the scene of the accident as he was trying to get to Peterson’s car, he immediately saw what needed to be done.

He began the practice of running the medical car behind the race cars at the start of a race for quick intervention, with the medical car equipped to deal with an emergency and with Watkins inside. Watkins also asked that an anesthesiologist and a medical helicopter for evacuation be at every track, and set the standards for circuit medical facilities.

Unfortunately, the series had another black period, in 1982, when Gilles Villeneuve was killed at the Belgian Grand Prix at Zolder and Riccardo Paletti died in an accident a month later at the Canadian Grand Prix. Watkins was on the scene each time, tending the drivers personally. That led to more safety innovations, and from then until the deaths of Senna and Ratzenberger 12 years later there were no fatalities at a race, although a driver died in a test between races.

As the cars became faster, and changed in design, Formula One had not noticed the danger signs mounting in the early 1990s. It was, of course, an age-old problem with car racing in general and with Formula One in particular.

Amid a push for safety, a study by the F.I.A. in 1999 found that 15 drivers had been killed in Formula One races between 1963 and 1982. Another 13 had been seriously injured, and it was a period during which for the most part there were far fewer Formula One races than today.

Although after the fatalities of 1982 there were plenty of safety measures put in place for both the cars and the tracks — the banning of skirts that ground the cars to make them faster, frontal crash tests, and a different placement of the driver in the cockpit — the effort was heightened after Senna died.

Headrests were created and the cockpit area was raised to avoid the driver being hit by wheels flying off the car; the wheels were attached with tethers to hold them on during accidents; even the design of the suspension was changed to avoid contact with the driver’s head. There was standardization of the removable seat fixing, for quick extraction, and survival cell modifications. The tracks themselves were modified to avoid dangerous corners and increase runoff areas — Senna had smashed into a wall — and circuit debris fence and other barriers were modified. Even helmet standards were controlled, and drivers began wearing a head and neck bracing system, called HANS, to prevent whiplash-like neck and spine injuries.

Watkins, in fact, had the perfect background for the job. Not only did he have a lifelong interest in racing, but he was a top medical man. His father had worked as a miner before opening a garage in Liverpool in the 1930s, first for bicycle repairs and then cars. Watkins worked in his father’s garage until he was 25. But his ambition was to be a doctor.

He graduated in medicine from the University of Liverpool in 1956 and then spent some time in West Africa with the Royal Army Medical Corps. He returned to England in 1958 to study neurosurgery. He first worked as a track doctor during a go-karting event at the Brands Hatch circuit in 1961 and then as a track doctor at the Silverstone circuit.

In 1962, he moved to the United States to work as a professor of neurosurgery at the State University of New York. There, he again took up working as a track doctor, this time at the Watkins Glen circuit.

In 1970, he returned to England to become the head of neurosurgery at the London Hospital, and he was simultaneously invited to work on the Royal Automobile Club medical panel.

He combined both a highly successful and respected career in medicine with his work in racing. In 1992, he founded the Brain and Spine Foundation, a charity designed to improve the prevention, treatment and care of people affected by disorders of the brain and spine.

Although he retired from his role as the F.I.A. track doctor in 2005, he continued to work with the F.I.A., developing various motor-racing safety programs until 2011.

But it was his personality and love and understanding of racing and drivers that made him such a memorable figure in the paddock.

“He was the most intensely charismatic human I have ever met,” said Gary Hartstein, an anesthesiologist and specialist in emergency medicine who worked for many years with Watkins at the track and now carries out his role at the Formula One races. “A brilliant guy, strong as a bull, but he knew when and where to apply it. He could be diplomatic and absolutely lovely when he had to be. And he could be an absolute powerhouse, nuclear bomb when he needed to be. And he finessed that so incredibly well throughout both his university career and in motorsport, and he got so much accomplished because he could do that.”

Bruno Senna, Ayrton’s nephew, who is driving this season in Formula One at the Williams team, which was the same team Senna was with when he died, confirmed the bond between his uncle and Watkins.

“Ayrton was very close to Sid and in my family we always had great respect for him, and we knew that he was one of the few real friends that Ayrton had in the paddock,” Senna said. “It’s difficult to make real friends in the Formula One paddock, and he was one of the few ones that Ayrton was fully comfortable with.”

The day before Senna died, after Ratzenberger’s death, the Brazilian was so affected that Watkins suggested he quit racing. He said that he, too, would quit racing, and that the two of them would go fishing together, which was a favorite pastime of theirs. Senna said he could not possibly quit, that it was his life. Watkins didn’t quit, either, which did not save Senna but was fortunate for generations of drivers to come.