Investigators look into possible criminal charges against the engineer who may have "nodded off" before the attack.
A union representative tells CNN that the train engineer in a NY crash "was nodding off and caught himself too late."
Former NTSB official Peter Goelz weighs in on the organization booting the rail union from its investigation.
Sleep expert Michael Breus talks about whether a change in sleep schedule could have contributed to the Bronx train crash.
A new law allows driverless cars to cruise on the streets of California.
Google parades its self-driving Prius on D.C. streets to garner support from lawmakers to make it street legal.