BOSTON — Legislation is making its way through the Commonwealth of Massachusetts that would prohibit unnecessary engine idling on or around school grounds.

Senate Bill 2628 calls upon the Registrar of Motor Vehicles (in consultation with the state Department of Education), the Department of Environmental Protection, the Executive Office of Public Safety and the Executive Office of Health and Human Services to adopt several engine-idling regulations.

The regulations include establishing a length of time that owners and operators of personal motor vehicles may idle their engines on school grounds and establishing circumstances under which prolonged engine idling is permitted, such as periods for defrosting, heating or cooling the vehicle, or periods for engine maintenance and inspection.

Those who violate the law would receive a $100 fine for the first violation and a $500 fine for a second or subsequent violation.

Moreover, the regulations would prohibit school bus drivers from idling a bus’ engine while waiting for children to board or disembark, and by extension, from igniting the engine an unnecessarily long period of time before leaving school grounds, unless the registrar determines that the engine must be fully engaged in order to operate safety devices, or that the idling prohibition would compromise students’ safety as they board and disembark.

Finally, the legislation stipulates that “no idling” signs must be posted at all schools’ loading and unloading zones by Aug. 1, 2009.

The Registrar of Motor Vehicles would notify all school bus drivers of the engine-idling regulations during their annual certification process.