Targeting a new frontier in the fight against smoking, California lawmakers may ban motorists from lighting up near young passengers. The measure would mark the first time that Californians would be prohibited from smoking legal tobacco products on private property not open to the public or employees. No state had passed such a vehicle smoking ban until this year, when Arkansas and Louisiana set a precedent by barring the practice when passengers are under 6 or 13, respectively. Assemblyman Paul Koretz, a West Hollywood Democrat who proposed California's ban, Assembly Bill 379, said some parents don't seem to know --...