The improved quality of vehicles continues to have an effect on passenger car maintenance costs, which decreased by 9 percent from 1999 to 2000 when comparing cents per mile. This information comes out of the seventh annual maintenance study conducted for Automotive Fleet by Associates Fleet Services, a fleet management company headquartered in Carrollton, TX. Mike Southwick, vice president of maintenance management for Associates, said the survey showed a good deal of stability over the past year when comparing vehicle miles per month. Other factors cited by Southwick as contributing to the 9 percent decline in costs are longer-life coolants and transmission fluids and lower tire prices brought about by the proliferation of tire vendors. And even though labor rates have increased, the national account pricing that a managed fleet services company has been able to secure has kept that increase from being reflected in fleet maintenance costs. "National account pricing is just one of the many ways a managed fleet program controls costs," Southwick said. "Not surprisingly, we still see the same three major categories carrying the bulk of the expenses," Southwick said. "If you look at operating costs, aside from fuel, the vast majority of money continues to be spent in preventive maintenance, tires, and brakes." Southwick also said the sample size of the survey has decreased because of the trend for fleets to migrate toward trucks, sport/utility vehicles, and minivans. As for the future, Southwick believes that only economic forces, including high inflation or a recession, could cause the loss of stability that has marked maintenance costs in the past several years. What is Incident Ratio? Incident ratio reflects the number of repairs per hundred vehicles. For instance, an incident ratio of 30 percent indicates 30 repairs per 100 vehicles. The figures shown reflect expenses beyond any manufacturer's warranty coverage. Cost data and number of incidents are for the most recent 12 months in service, regardless of the miles traveled during the 12 months.