By Insure.com Several insurers, including Esurance, have established their own proprietary rating symbols that take multiple factors into account when pinpointing risk exposure. Another established rating system is the rating manual developed by Jersey City, N.J.-based Insurance Services Office (ISO), an organization that compiles loss data for the insurance industry. ISO¡¯s manual of automobile rating symbols assigns vehicles to one of 27 classifications. 2. Dodge Ram Pickup While nobody wants to buy a car with a high insurance premium attached, there is good news for individuals who bought cars on the Most Expensive to Insure list. 2005 marked a year when many insurance carriers were able to offset these higher premiums by passing along premium savings to customers via other means. David Biewer, vice president of actuarial, for San Francisco-based Esurance, which provides personal auto insurance direct to consumers online, says.