The California Air Resources Board has scheduled public hearings in early December to discuss a proposal to broaden regulations on transit bus emission standards, particularly in regard to particulate matter. Topics to be addressed at the workshop include harmonizing the state's urban bus engine standards with the EPA's 2007 heavy-duty diesel engine standards and early introduction of the 2007 technology. Board staff is proposing allowing 2007 engine technology, which means engines meeting no higher than 1.2 g/bhp-hr NOx emission standard, to be introduced during 2004-06. The proposed regulation modifications would apply to all California transit agencies, including systems that do not own any urban buses and currently are not subject to the fleet rule for transit agencies.