FILE - In this Aug. 2, 2016, file photo, authorities investigate the scene of a charter bus crash on northbound Highway 99 between Atwater and Livingston, Calif. U.S. officials are abandoning plans to require sleep apnea screening for truck drivers and train engineers, a decision that safety experts say puts millions of lives at risk. Photo: Scott Smith /Associated Press / Copyright 2016 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistribu