"I don't have a timetable and I don't think there is a timetable," NASCAR president Mike Helton told The Associated Press on Sunday. "A lot of things still have to be addressed, but right now the process of doing that is more active than it has ever been."

NASCAR has long been hesitant to mandate such measures, choosing instead to recommend safety devices. But the sanctioning body has been under increased pressure to require restraints in light of four deaths in its various series since May 2000.

A fifth driver, Blaise Alexander, was killed Thursday night in an Automobile Racing Club of America event at Lowe's Motor Speedway. ARCA is not associated with NASCAR, but Helton said Alexander's death sent the same ripples through his garage area as if one of its drivers had died.

"It puts everybody in motorsports on edge and it should," Helton said. "It's frustrating. We're frustrated, the drivers are frustrated, everyone in motorsports is frustrated. But I've long maintained we will not react just for the sake of reacting."

NASCAR has drawn criticism during the past 17 months for not requiring drivers to wear head-and-neck restraints.

It is believed the devices possibly could have prevented the skull fractures that killed Dale Earnhardt, Adam Petty, Kenny Irwin and most recently Alexander. Tony Roper, who drove on NASCAR's truck series, died of neck injuries.

Helton's thoughts on the devices, first reported Sunday by The Charlotte Observer, indicate the sport might be moving close to requiring them.

"It is more active than it has ever been -- the use of them, the development, the conversations, the technology of continuing to improve them -- all of that is more active today than it has ever been," Helton said.

"There are still questions and concerns, but at this time the activity around getting them fixed is at an all time high."

Of the 43 drivers in the field for Sunday's UAW-GM Quality 500, only driver Tony Stewart did not wear one of the two available restraint devices. Short of a mandate, Helton said he could only "continue to educate" Stewart about the advantages of using either the HANS or Hutchens device.

Helton said NASCAR would not mandate a single device, instead leaving it up to the drivers to choose. That, he added, would allow for continued development and improvement.

NASCAR is still determining which of its 13 different divisions would need such a mandate, Helton said. The push right now is for the sanctioning body to require the use of restraints in the Winston Cup, Busch and Trucks series.

Meanwhile, Helton also said NASCAR was looking into concerns over the stiffness of cars.

Many in the industry believe the stock cars are too rigid and transfer too much energy to drivers in crashes. NASCAR is working on building and testing chassis' to address that, but said it most likely will be more than a year before there are major modifications to race cars.

"I would have rather had something two years ago, but I don't think we'll have significant changes in the cars by 2002," Helton said.