The "Fitch Highway Barrier System", invented by race car driver John Fitch, comprises a series of such impact attenuators often found in a triangular.

The "Fitch Highway Barrier System", invented by race car driver John Fitch, comprises a series of such impact attenuators often found in a triangular arrangement at the tip of a guardrail between a highway and an exit lane (the area known as the gore), along the most probable line of impact. The barriers in front contain the least sand, with each successive barrel containing more; so that when a vehicle collides with the barrels they shatter, the kinetic energy is dissipated by scattering the sand, and the vehicle decelerates smoothly instead of violently striking a solid obstruction, reducing the risk of injury to the occupants