U.S. Environmental Protection Agency has published a summary of
the state laws and regulations that restrict idling. This list includes
provisions from 18 states and the District of Columbia.
in some states are the restrictions statewide and apply to all diesel
commercial vehicles (and in some cases to private passenger vehicles).
The compilation includes the citation of the statute, regulation
or ordinance under which the violation is created however, does
not include the range of penalties that may be imposed or how closely
jurisdictions enforce anti-idling restrictions.
of the anti-idling limits range anywhere from three to 30 minutes,
with Montana being the most liberal on the rule, allowing no more
than two hours of idle time during a 12-hour period when the state
issues an air quality advisory ruling.
but not all of the states have included idling exemptions in certain
circumstances such as traffic conditions, loading and unloading,
repairs or inspections, and for auxiliary purposes.
read the list, go to: http://www.epa.gov/orcdizux/retrofit/documents/s03002.pdf.