PHOENIX – Federal safety officials said Thursday they would investigate a crash in which authorities said a milk tanker moving too fast had collided with seven passenger vehicles on the Phoenix Highway, killing four people and killing wounded at least nine.
The devastation came late Wednesday after the tanker “failed to slow down due to traffic jams,” the Arizona Department of Public Safety said in a statement.
The National Transportation Safety Board said it was sending nine investigators to conduct a crash safety investigation in collaboration with the Arizona Public Safety Department.
Among the questions NTSB investigators will investigate is whether the crash could have been prevented if the tanker had been equipped with electronic safety devices, said on-board spokesman Chris O̵
Six of the nine people injured in the crash were taken to hospitals in critical condition, a statement from the Phoenix Fire Department said. The four men and two women ranged in age from 22 to 45. Details of the four people killed were not immediately released.
After the initial collisions, the tanker platform trailer detached and passed through the middle wall of the highway and ended up on the side in the lanes moving in the opposite direction, the State Department of Public Safety said.
Authorities ruled out the possibility that the driver was disabled, the department said. The trucker has not been identified.
There are currently no federal requirements for semi-finished products to have a forward collision warning or automatic emergency stop, although systems are becoming common in smaller passenger vehicles.
Systems use cameras and sometimes radar to see objects in front of a vehicle, and they either warn the driver or slow down and even stop the vehicle if it is about to hit something.
O’Neill said investigators would determine if the tanker had any state-of-the-art safety equipment and, if so, how it performed in the crash. If there were no systems, they would determine whether “collision avoidance technology would mitigate the severity or prevent it altogether,” he said.
The NTSB, he said, has investigated several crashes involving large trucks hitting stopped or delayed traffic. As early as 2015, the NTSB recommended that manufacturers immediately include electronic safety systems as standard equipment. At the time, the agency said the systems could prevent or mitigate more than 80% of rear-end collisions, which cause about 1,700 deaths and half a million injuries a year.
Twenty car manufacturers, representing 99% of new passenger car sales in the United States, signed a voluntary agreement with the government in 2016 to make the features standard for all cars by September 1, 2022, and many companies are moving toward that goal.
O’Neill said the team that headed to the crash site included members with experience in road hauling, highway design, passenger protection, human characteristics, vehicle factors and technical disaster recovery.
Investigators will also try to determine if the driver’s distraction played a role, he said.
“Our investigators will look at the people involved in the crash, the vehicles involved in the crash, and the environment in which the crash occurred,” O’Neill said.
Investigators usually stay on site for five to 10 days and publish a preliminary report 30 to 90 days after the fieldwork is completed. Investigations usually take 12 to 24 months.