pay-as-you-drive insurance
n.— «A few years later, Edlin was serving on the President’s Council of Economic Advisers when he floated an idea that economists had long found attractive: pay-as-you-drive (PAYD) insurance. It seemed like an obvious solution. Since no one expects to pay the same price for, say, a 60-minute massage as they pay for a 15-minute massage, why should people pay the same for insurance no matter how many miles they drove?» —“Not-So-Free Ride” by Stephen J. Dubner, Steven D. Levitt New York Times Apr. 20, 2008. (source: Double-Tongued Dictionary)