1. filling pipe insert keeps larger, leaded-fuel nozzle from being inserted
  2. gas cap tether does not allow the motorist to drive off without the cap
  3. gas cap is fitted with ratchet to signal proper tightness and prevent over-tightening.


Mistake-proofing category: Mistake prevention
Setting function: Physical
Regulatory function: Shutdown
Source: Off-the-shelf


Secondary Problems (side effects, weakness or concerns) with this example:


Sources of Supply:

See also:

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