The introduction of hydrogen buses is expanding worldwide. Hydrogen is recognized as a dangerous source of energy, and safety measures in the hydrogen-powered Elec bus supply plan are required. Hydrogen gas leakage can be one of the most critical factors in bus operation. Particularly, when a hydrogen vehicle leaks continuously during its operation, the incident can lead to fatal accidents. Currently, information on hydrogen leakage is accumulated through a collection sensor mounted within the vehicle and is measured when the sensor detects a leakage. This study proposes PHL(Pseudo Hydrogen Leakage) as an additional indicator of hydrogen safety leakage to be evaluated and monitored. The PHL indicator is applied to Regulation Article 17 criteria of the Automobile Rules.