The S-1 Gard Danger Zone Deflector is a public transportation safety device consisting of a curved polyurethane guard, mounted in front of the right rear wheels of transit buses, designed to deflect a person out of the path of the wheels in order to prevent injury or death. It is currently installed on bus fleets in major cities such as Los Angeles, Washington, D.C., San Francisco and Baltimore, among others. The S-1 Gard was invented and patented by Mark B. Barron in 1994.

The S-1 Gard is recommended by the Transportation Research Board as a strategy for mitigating bus collisions with pedestrians, and has been credited by public transit officials with significantly reducing, if not eliminating, injuries and fatalities involving the rear right wheels of transit buses.

For more information, visit www.s1gard.com or read the S-1 Gard article on Wikipedia.