* Fuel tank design: The YJ's fuel tank is generally located in a relatively protected position, and the tank itself helps contain fuel spillage in the event of a rollover.
* Fuel lines and connections: The fuel lines are routed to minimize the risk of rupture in a rollover. These are robust enough to withstand some degree of impact and movement.
* Gravity: In many rollover situations, gravity will assist in preventing fuel from flowing freely in an uncontrolled manner.
While there isn't a dedicated "rollover valve," fuel system components, tank placement, and the inherent design of the system are the primary safety mechanisms to prevent fuel spillage in a rollover accident.