Chattanooga Police Officer Joe Warren said school bus driver Johnthony Walker must have been going about 20 miles per hour over the speed limit before he swerved off narrow, winding Talley Road. The crash killed six Woodmore Elementary school children, and Walker faces criminal charges. At a preliminary hearing, Warren testified that there was no indication Walker applied the brakes before the crash, and bus video showed Walker using his cell phone while children were on the bus, which is