Abstract: A loose wheel restraint safety system provides bolt-on support brackets in a system for attachment to the chassis or to the body of a vehicle, to which brackets wheel restraint bars are detachably mounted. The brackets of the system are located adjacent the wheels of the vehicle, such that the restraint bars, when mounted, are located in close proximity to the tires and extend horizontally across the wheel. The system elements, when bolted in place form, in combination with the adjoining vehicle bed or chassis portions, substantial wheel enclosures that permit each wheel and rim to turn freely upon its axle or spindle, while restraining the wheel against lateral deviation from its axle. The system is applied to each outer wheel of a multi-wheel rig, to restrain a break-away wheel against run-away, such that the driver, upon observing the situation, can pull the rig off the road and to a halt.