Fleet card providers like WEX use these codes to manage tax exemptions. An "Undefined" code often means the tax-exempt program cannot verify the fuel type, and therefore, standard taxes may apply by default.
Technical manuals for hardware like the Gasboy EMV system list these as "Undefined Fuel" blocks reserved for future or private use. undefined fuel-reserved for proprietary
Further reading: SAE J1939-71 (Vehicle Application Layer), ISO 14229 (UDS), and the ICU International Components for Unicode guide to resource bundles. For fuel chemistry, refer to ASTM D4814 (gasoline specifications). Fleet card providers like WEX use these codes
By adopting a balanced and sustainable approach to fuel reservation for proprietary use, we can promote energy security, economic growth, and environmental sustainability, while ensuring that the benefits of energy resources are shared equitably among all stakeholders. Though officially unconfirmed
Though officially unconfirmed, several declassified military aviation documents reference a “Proprietary Reserve” of 7–12% total tank volume in certain special operations drones. The reserve is not accessible via standard fuel gauges and is isolated by a physical membrane. Pilots are instructed:
