Two insurers that together cover nearly 25 million vehicles in the US have quietly begun making drivers of bigger vehicles pay more for liability insurance, the New York Times (NYT) reports. Allstate Insurance Company and the Progressive Insurance Group, the nation's second- and fourth-largest insurers, confirmed to the newspaper that they had begun raising the cost of liability insurance for many big, high-riding vehicles while lowering premiums for the cars that are owned by most Americans.