Tire Walls are a type of
energy absorbing barrier used primarily on
race courses. Tire walls were originaly developed by famed American race driver
Phil Walters who both retired and became safety obsessed after his co-driver
Pierre LeVeigh suffered a horrendous crash at
Le Mans.
Walters realized that tires were simultaneously soft and stiff. Plus they were plentiful at race tracks, where drivers are always tearing their tires off. By piling them at a thickness of about four or five feet, a thick barrier could be created that could stop an out of control race car without damaging it excessively and harming the driver. The tires deflected, absorbing energy.
At the simplest level, tires are merely stacked loosely, which is often the case at club tracks like Nelson Ledges. They are very effective at shedding speed, but the tires tend to fly about and can flip the car, albeit gently.
Another method is to restrain the tires by stacking them neatly, and wrapping a net around them. This is a softer barrier than banded tires, and more stable than loose tires, with fewer flips. Tires still do fly about and banded walls they take longer to repair.
A banded wall may use netting, but the tires are assembled in blocks that are connected together, sometimes by nut and bolt. Flexible tubes may be run through the center in order to stabilize the tires vertically. These walls rarely fly and or flip cars, and they are faster to repair after an impact. However, they are not so energy absorbant as other tire walls.
Tire walls are usually placed before a harder barrier such as a guardrail or some concrete wall. The work better when a gravel trap or some other type of speed shedding area guards them. Such systems are very good at stopping cars while absorbing the impact themselves. Tire walls have saved lives, and wallets.