Firm says a rise in the number and severity of car accidents is to blame.
Insurers have been predicting that auto insurance rates would rise since last spring. Allstate blamed a rise in the number and severity of accidents for the increase, which is scheduled to take effect May 18. The premium war took its toll. Insurers and analysts predict more companies will boost their rates now that Allstate has taken the lead. Rising repair costs also are hurting insurance companies' bottom lines, said Carol Thorp, spokeswoman for the Automobile Club of Southern California, the state's fourth-largest insurer.