Run-off zones PDF Print E-mail

Some of the most important safety features in Formula 1 are alongside the track. Generous run-off zones help reduce the speed of a car that has come off the track, while tyre stacks absorb the impact energy of the car when hit. Both the run-off zones and tyre stacks play a crucial part in the high safety standards of top-class motor racing.

Safety first! - Run-off zones

Allianz Safety Check: Istanbul Racing Circuit

 Video available!

Although the safety systems at Formula 1 tracks have been greatly improved in recent years, the authorities refuse to be satisfied with the progress. Frank Dernie at WilliamsF1 Team is not the only one to demand that “the improvement of track safety must remain an important development goal in Formula 1 in the future.”

If the car comes off the track because the driver has misjudged a braking point or is struggling with a technical fault, the run-off zone acts as a sort of emergency brake. The gravel traps are about 25 cm deep and filled with spherical gravel stones with diameters of between 5 and 16mm in diameter.

The stones are designed to generate as much frictional resistance as possible – like sand scattered on an icy pavement – and so reduce the speed of a skidding car quickly and effectively. However, there is often a practical problem with this concept: with a ground clearance of just 50mm and a smooth underbody, the cars often slide over the surface of the gravel trap without braking sufficiently. There is also the danger they can be flipped by the heaped gravel and roll over.

The loose gravel traps are therefore being replaced by rough tarmac. It has the advantage of allowing the drivers, in some cases, to bring their skidding car back under control. Moreover, if the car does roll, the roll-over bar does not sink into the soft surface: another safety bonus for the drivers. WilliamsF1 Team driver Mark Webber thinks run-off zones made of tarmac are safer, but makes an important point: “Many drivers exploit that, and sometimes even overtake. In that way, they take a much bigger risk because the consequences of a spin are not so dramatic.”

Run-off zones are not a logical option on every section of track. For acute impact angles of less than 30°, the Fédération Internationale de l’Automobile (FIA) recommends a smooth, continuous and vertical track boundary. Ideally, the cars slide along this wall or crash barrier and dissipate energy and speed. For less acute angles, on the other hand, gravel traps and tyre stacks are absolutely indispensable. A tyre barrier has to be at least as high as the boundary wall behind it (at least one metre) and must consist of between two and six rows of tyres. Normal car tyres are often used, but they must not be too worn to ensure they provide enough resistance in an impact. All the tyres have to be bolted together: the front row is covered and reinforced with a 12 mm-thick rubber strap. Ideally, tyre stacks absorb about 80% of the impact energy.

On some sections of the city track in Monaco, which is lined with 32 km of crash barriers and has hardly any run-off zones, full water tanks have been used since 1995 as an alternative to tyre stacks. So-called “soft walls” were developed for the full-throttle banked corner at the Indianapolis Motor Speedway, filled with compact sheets of a polystyrene-like synthetic material and secured to the concrete wall with metal cables. Because it is a continuous system, it yields as a single unit in the case of an impact: the car does not get jammed and can slide smoothly along the barrier and slow down. Air-cushion fences are still in the test phase.

Despite the huge progress in both passive and active safety in passenger cars, coming off the road is still one of the most serious risks to road traffic. ESP, or Electronic Stability Programme, is the most effective system to prevent skidding accidents, but roadside measures are an important second step towards preventing accidents and reducing the consequences of accidents.

“First of all, the road should be laid out so drivers will keep as intuitively as possible to the speed for which it is designed,” explains Dr. Christoph Lauterwasser from the Allianz Center for Technology. “Crash barriers are sensible and necessary, for instance to prevent crashing into dangerous obstacles close to the road. However, a run-off zone is even better than driving into a crash barrier.”

Whichever system finally asserts itself in Formula 1, one thing is certain: the race to optimise track safety will never cross the finishing line.

Mark Webber, WilliamsF1 driver:

“The track near Istanbul is not only the newest and one of the safest in Formula 1, but also one of the most interesting. It’s a demanding up-and-down track, which we drive anti-clockwise. The biggest challenge is the incredibly quick Turn 8, which consists of four different straight sections, each of which has a different radius. That makes it extremely difficult to find the ideal line. Thanks to the generous run-off zones, the safety standards are exemplary.”


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Last Updated on Wednesday, 21 May 2008 21:59

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