Nellis Air Force Base (AFB) Airfield Driving Practice Test

Red with white lettering signals an action you are required to perform. This type of sign conveys a command that must be followed to keep operations safe, such as “Hold Short” or “Stop.” It’s different from informational signs, which provide directions or general information without enforcing a specific action, and from jet blast or circle-of-safety signs, which warn about hazards or indicate boundaries rather than issuing a direct instruction. So, the sign that fits the description—red background, white lettering, and an instruction you must follow—is a mandatory sign.