This article is from the The Monster Truck FAQ, by Jeff Hawkins with numerous contributions by others.
A. The drivers wear fire resistant suits, gloves, a helmet liner and
shoes. They are held into the seat by a standard 5 way racing harness.
The helmets are racing quality Snell Foundation approved (Minimum
rating is Snell 90). Most drivers also wear Helmet Restraints (Straps
running from underarm to clips on sides of helmet)!
Drivers must wear a neck collar and some drivers wear a `kidney belt'
to help absorb the impact compression forces on the spine and neck.
All MTRA certified race trucks must be equipped with a approved
onboard fire retardant system. The vehicle must also have a Halon
or ABC type 2-1/2 lb. (min.) fire extinguisher within the driver's