§7554 Urban bus standards

Summary

The Administrator must write rules by January 1, 1992, that apply to urban buses starting with model year 1994. The rules must use the best technology likely to be available while considering costs, safety, energy, and time to prepare. For 1994 and later buses, particulate matter (PM) emissions must be no more than 50% of the PM level allowed by the heavy-duty diesel standard in effect on November 15, 1990. The Administrator can raise that allowed level if 50% is not technically possible, but never above 70%. The Administrator must decide during the rulemaking whether the 50% cut is achievable. Beginning with 1994 model buses, the Administrator must test a sample of buses each year in real operating conditions. If those tests show buses do not meet the PM standard over their useful life, new buses bought or put into service in metropolitan areas with a 1980 population of 750,000 or more must be built to run only on low-polluting fuels and must be operated that way. The Administrator will set the pass-fail rate and must phase in the fuel requirement over five model years starting three years after the finding, reaching 100% in the fifth model year. The Administrator may extend the fuel rule to smaller metro areas for public health reasons. Within 12 months after November 15, 1990, the Administrator must issue rules covering buses in those large areas that were not previously covered and that have engines replaced or rebuilt after January 1, 1995. Within 18 months after November 15, 1990, the Administrator must set enforcement, testing, and sampling procedures that reflect real-world use. Urban bus will be defined by the Administrator’s rules. Low-polluting fuel means methanol, ethanol, propane, natural gas, or any fuel the Administrator finds similarly low in pollution; methanol means at least 85% methanol unless the Administrator sets a higher percentage.