Although Michael Schumacher survived an accident similar to the one that killed his predecessor as Formula One's top star, some drivers say the circuit still isn't doing enough to ensure their safety.

A tire barrier softened the blow when Schumacher slid off the Silverstone road course in the British Grand Prix, allowing the two-time series champion to escape with a broken leg. Five years ago, three-time champion Ayrton Senna died after hitting an unpadded concrete wall in Imola, Italy.

"I'm lucky to be alive," said Schumacher, who will miss several races while his right leg heels.

But race winner David Coulthard and Eddie Irvine, Schumacher's Ferrari teammate, say gravel traps designed to slow cars that slide off the pavement are dangerous. They say FIA, the F1 governing body, needs to recognize that.

"They have to slope up or they don't do any good," Irvine said. "The car has to be forced into the gravel."

When Schumacher's car left the racing surface at about 130 mph, it hit the trap and seemed to gain speed.

"That one didn't slope up, as 90 percent don't do in any circuit around the world," Irvine said.

But FIA president Max Mosley, who has championed many of the new safety measures, says there's "no real evidence" that such a sloping design would have slowed Schumacher's car.

...Asphalt probably would have been more effective than gravel in slowing Schumacher when his rear brakes apparently locked up.

Grooved tires were introduced in 1998 to put a cap on ever-increasing speed. A fourth groove was added this year.

Other little-noted safety measures mandated by the FIA since Senna's death have included:

- Partially collapsing, energy-absorbing steering columns.
- Improvements in the impact resistance of the nose cone.
- Additional padding in the cockpit.
- More protection around the fuel cell.
- Higher cockpit sides to protect the driver's head.

In the top high-tech sport in the world, there also was criticism of the seemingly low-tech, three-layer tire barrier that absorbed the impact of Schumacher's crash.

But Andrew Benson, the Grand Prix editor of the British magazine Autosport, said a stack of tires is the best shock-absorbing device for F1 cars.

"It seems anachronistic that impact should be cushioned by layers of old tires," he said. "But research has shown that tire barriers are in fact the best and most cost-effective thing for Formula One cars to hit - if they must hit something."

Mosley, Ferrari team manager Jean Todt and Schumacher agreed that the 30-year-old German was saved by the new safety measures.