is this device called H.A.N.S.
It stands for "Head And Neck Support".
It's a device that the drivers wear around their shoulders, kind of like a
"U" shape device, which has an attachment at the back, for a short strap
that goes directly to the back of the helmet.
The way it works is that, it prevents the head from moving too far forward
in a front-on crash. When such an accident happens, the neck muscles on a
particular driver may be strong, but the problem occurs at the base of the
skull where the breakage actually occurs.
They also said that in Nascar, it's not compulsory, as it is in other auto
sports. Only 4 or 5 drivers are currently using the device. They also said
that the last 7 deaths that have occured, would have been prevented if the
drivers were wearing this device.
According to the story, Dale knew about the device and had seen the videos
of crash tests, but he didn't want to use it.
If you like, you can read more about it here:
http://www.racesimcentral.net/