It was twenty years ago today that that a drunk driver’s pickup truck struck a church group’s school bus on Interstate 71 near Carrollton, Kentucky, killing 27 people. The group was on its way home to Radcliff from an amusement park outing.It remains the worst drunk driving wreck in U.S. history.The fiery crash prompted many states to toughen their drunk driving laws, and National Transportation Safety Board specialist Danielle Roeber says it also resulted in an overhaul of school bus safety standards in Kentucky."The awareness that there were issues with evacuation, fuel integrity, flammability of materials on the bus generated a lot of activity to the point that you have more than your entrance at the front of the bus and the exit at the back," Roeber said.The driver of the pickup, Larry Mahoney, was convicted of manslaughter and other offenses and spent nearly 11 years in prison.