In New York, drivers are not supposed to leave cars running unnecessarily for more than five minutes without moving.
But Long Island Rail Road and Metro-North workers kept highway vehicles running while they were parked for a combined total of more than 20,000 hours each month.
In one incident, investigators say two trucks idled for a combined 25 hours over one weekend in Queens.
Inspector General Barry Kluger calls the practice illegal and environmentally destructive.
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