AUGUSTA - Operators of commercial vehicles in Maine who leave their motors idling for long periods will have to change their habits if a bill in the Legislature is enacted.

Rep. Jon Hinck's bill, modeled after a New Hampshire law, has won preliminary House and Senate votes of approval. The Portland Democrat says the law would conserve energy and promote cleaner air.

The bill would prohibit some commercial vehicle operators from letting their vehicles idle for more than five minutes when the temperature is above freezing. It would not apply to emergency vehicles or those stuck in traffic.

Hinck cited federal figures showing that needless truck idling nationwide consumes more than a billion gallons of diesel fuel and produces 11 million tons of carbon dioxide per year.