3.3.1 Driver Restraints
Seat lap belts are required in all cars, and must be installed in cars with passive restraint systems that do not include a lap belt. Installation and the use of shoulder belts or harnesses is strongly recommended, however non-factory upper body restraints may only be used in open cars, cars with targa-tops in the open position, or cars with T-tops in the open position when two conditions are met:
- a. The roll structure must meet either the requirements of Appendix C or Section 9.4 of the GCR.
- b. The top of the roll structure may not be below the top of the driver’s helmet when the driver is in the normal driving position.