Officials will look into what factors may have caused the wreck and how to prevent similar accidents, NTSB Vice Chairman Christopher Hart said Friday.
"We've been interested for some time in school bus safety," Hart said. "We're also interested in construction zone safety."
Grief for 2 Teens Dead in Mo. School Bus Crash
2 Killed, Dozens Hurt in Mo. School Bus Crash
The accident happened Thursday on Interstate 44, about 40 miles from St. Louis. A semi cab slowed for road construction and was struck by a GMC pickup. Two buses carrying high school band students then slammed into that wreck, killing a 15-year-old student and the driver of another vehicle.
No charges have been filed in the wreck. Missouri State Highway Patrol Cpl. Jeff Wilson said it will be up to Franklin County prosecutors to decide that.
Hart said the NTSB isn't interested in pointing fingers.
"We are here to determine the cause of the accident, not looking at blame," he said.
Among other issues, the NTSB will examine whether seat belts on the bus could have helped.
He said investigators will also consider the possible benefits of accident-avoidance technology for vehicles such as school buses that would provide some warning to drivers about impending slowdowns and automatically apply brakes.
Although every state has laws requiring seat belts or restraints for children in passenger cars, only six states (New York, New Jersey, California, Florida, Louisiana and Texas) have laws requiring lap or three-point seat belts on large school buses.
In some cases only newly-purchased or recently manufactured buses fall within the requirement.
In Louisiana and Texas, they are only required if school districts can get funding for them.
Federal standards on school bus safety from the National Highway Traffic Safety Administration (NHTSA) only require three-point belts on smaller school buses (those weighing less than 10,000 pounds).
In Missouri, where yesterday's deadly crash occurred, seat belts are not required in large school buses, but are recommended if school districts can obtain funding.
It was not clear if the buses in yesterday's crash had seat belts.
According to a 2006 study in the journal Pediatrics, there were on average 17,000 school bus-related injuries treated in U.S. emergency rooms annually from 2001 to 2003, with motor vehicle crashes accounting for 42.3% of them.
A 2009 report by the Transportation Research Board of the National Academies states that data from 1991-1999 indicates on average 5 children are killed each year while rising in a school bus; 15 more pedestrian children are killed annually in school bus-related accidents.