However, there are ways to stop fuel flow:
* Inertia switch (fuel pump inertia switch): This safety device, often located in the passenger compartment, can be tripped in a collision, cutting off fuel to prevent fire. This isn't a deliberate cut-off, but it acts similarly.
* Fuel pump relay: Disconnecting the fuel pump relay will stop fuel flow. This requires some mechanical knowledge.
* Computer Failure: A catastrophic failure in the engine control module (ECM) could theoretically cut off fuel flow, but this isn't a designed feature.
In short, there's no simple on/off switch, but there are mechanisms that can interrupt fuel delivery.