CHARLOTTE, N.C. (AP) — International Speedway Corp. is developing a plan for the installation of additional SAFER barriers at Daytona and Talladega, and will review the safety standards at its other racetracks.The renewed focus announced Tuesday by ISC President John Saunders comes three days after NASCAR star Kyle Busch broke his right leg and left foot in a crash into a concrete wall at Daytona International Speedway.Busch left a Daytona Beach, Florida, hospital on Tuesday and was transferred to another facility in North Carolina for further treatment.Busch was injured Saturday in the season-opening Xfinity Series race when his car hit an interior wall that did not have a Steel and Foam Energy Reduction barrier.After his accident, Daytona president Joie Chitwood III vowed to cover every inch of the speedway with SAFER barriers.Daytona is owned by ISC, the sister company of NASCAR.Saunders said ISC is "developing a significant plan" for more impact-absorbing technologies that will not be limited to SAFER barriers for Daytona and Talladega.ISC will also immediately review Phoenix International Raceway and Auto Club Speedway in Fontana, California, as both tracks host NASCAR races in March."We will utilize all available tools to ensure the safety of the drivers and our fans.