Chaunte Williams, 13, holds up three candles as she takes part in a vigil Thursday, March 12, 2015, in Ferguson, Mo. Two police officers were shot early Thursday morning in front of the Ferguson Police Department during a protest following the resignation of the city's police chief in the wake of damning U.S. Justice Department report. (AP Photo/Jeff Roberson)

Calm prevails in Ferguson after shooting of police officers

Dozens gathered for a candlelight vigil Thursday night, where they expressed sympathy for the wounded officers. They also prayed for peace as Ferguson moves forward in the wake of a scathing Justice Department report on racial bias in its law-enforcement practices.

A truck passes over the train tracks near a sign listing an emergency number for railroad problems on Tuesday, March 10, 2015, in Halifax, N.C.  A train collided with a truck, Monday injuring 55 people.  The truck with a state trooper escort become stuck in the crossing but no calls were made to Amtrak about the problem, even though the sign should have been visible to the truck driver.  (AP Photo /Jonathan Drew)

Truck driver in N.C. Amtrak crash has history of violations

Federal regulations require motor carriers to conduct background investigations before hiring truckers, but the companies have wide discretion when deciding whether to hire someone with poor driving records or criminal convictions.