During the third day of the trial, witnesses told the jury that Williams was swerving, straddling lines and speeding up and slowing down before crashing, The New York Times reports.

Williams’s lawyers insisted that the bus was nicked, or cut off, by a tractor trailer.

The crash, that took place on March 21, 2011, on I-95 in the Bronx, killed 15 passengers. Williams is being tried on charges of manslaughter and criminally negligent homicide.