A Kingman man was arraigned Wednesday on four charges of manslaughter in the Golden Valley collision that killed four Mohave Generating Station workers.
Daniel Martin Brackney, 22, formally heard the charges by video link with Kingman Justice Court.
He is being held in Mohave County Jail on $250,000 bond
Brackney also has been charged with two counts of aggravated assault in the collision Friday, when his 2000 Ford pickup struck the rear of a van with six power plant workers heading west on state Highway 68.
The van went out of control and flipped in the median killing Eric Ruiz, 33, Roy Latimer, 55, John Walker, 52, and Dan Zasadni, 49.
Brackney and a passenger were heading east to Kingman from Laughlin.
Brackney had stopped the truck briefly then got back on the highway heading in the wrong direction, westbound back toward Laughlin, when the collision occurred, Arizona Department of Public Safety stated.
DPS's initial investigation found "the collision to be alcohol related" but the Mohave County Attorney's Office had not released Brackney's blood alcohol level results as of Wednesday.
A DPS investigation also has not yet estimated the speed of Brackney's truck.
Ruiz, Latimer, Walker, Zasadni and two other passengers were heading to work at the Southern California Edison energy plant near Laughlin around 6:15 a.m.
All were from Kingman except for Zasadni, who was from Golden Valley.
The other passengers, Robert Mansfield, 55, and Russell Pewsey, 38, were airlifted to University Medical Center in Las Vegas.
Both have been released.
Brackney's passenger was also arrested for misdemeanor warrants.