Roland Walter Ratzenberger (German: [ˈroːlant ˈratsn̩bɛrɡɐ]; 4 July 1960 – 30 April 1994) was an Austrian racing driver, who competed in Formula One at three Grands Prix in 1994.

After finishing third in the 1989 British Formula 3000 Championship and retiring from his 24 Hours of Le Mans debut, Ratzenberger moved into Japanese motorsport with Toyota.

During qualifying for the San Marino Grand Prix at Imola, Ratzenberger died as the result of a basilar skull fracture sustained in an accident at the Villeneuve Curva, colliding with a concrete barrier at 225 km/h (140 mph) in his Simtek S941.

The weekend became notorious for the fatal accident of Ayrton Senna the following day, with both deaths leading to widespread safety reforms and the re-establishment of the Grand Prix Drivers' Association.

[2] As a teenager, he discovered that racer and Formula Ford team owner Walter Lechner was based nearby and, while studying at a technical school, began to hang around the workshop.

[2] In the winter of 1991, in Monaco, and after what Adam Cooper described as "a whirlwind courtship", Ratzenberger married the former partner of another driver, becoming stepfather to her son from a previous relationship.

However, the next round at the TI Circuit in Aida went much better, as he not only managed to qualify, but finish in a very commendable eleventh place, even considering that he was the only driver who had raced at the venue before.

During the first qualifying session on Friday 29 April, he asked the more experienced Brabham to test his car out; the Australian vindicated Ratzenberger's assessment of the brakes, which had been troubling him at the previous races.

[7] The session was overshadowed when Jordan driver Rubens Barrichello hit a kerb at the Variante Bassa corner; his car, travelling at 225 km/h (140 mph), was sent airborne, and collided with the tyre barrier.

[5] Unknown to him, the minor incident had damaged his front wing; after a spin at the Tosa hairpin the previous lap, as he tried to turn into the high-downforce Villeneuve corner, it broke and became lodged under the car, which crashed into the outside wall at 314.9 km/h (195.7 mph).

He had suffered three individually fatal injuries: a basilar skull fracture, which was named as the official cause of death; blunt trauma from the front-left tyre penetrating the survival cell;[12] and a ruptured aorta.

I decided to race, really for the guys.Ayrton Senna commandeered an official car to hurry to the medical center; he learnt of Ratzenberger's death from friend and neurosurgeon Sid Watkins.

Paul Belmondo was reported to have been offered the final position on the grid but declined, out of respect for Ratzenberger and on the grounds that he had not earned that race spot.

[15] During the seventh lap of the race the following day, Senna's car ran wide at the Tamburello left-hander and struck an unprotected concrete barrier at 233 km/h (140 mph), resulting in multiple fatal injuries.

Due to drive later that year in the Le Mans 24 Hours for Toyota, Ratzenberger's name was left on the car as a tribute, with his friend Eddie Irvine taking his place at the wheel.

The reformed association subsequently pressed for thorough improvements to safety after the Imola crashes and others during 1994; for 2003, the FIA mandated the use of the HANS device, designed to prevent the type of injury suffered by Ratzenberger.