National Transportation Safety Board Chairman Deborah Hersman said this week it's clear the pickup driver was manually, cognitively and visually distracted.
In connection with the findings, the NTSB recommended on Tuesday that states ban all driver use of cell phones and other hand held electronics, except in times of emergency. The ban should apply to both hand held and hands-free electronics, the Board said.
Investigators said the young driver sent six texts and received five texts just before his pickup crashed into the back of a tractor truck, beginning a chain collision. The pickup was rear-ended by a school bus, which in turn was rammed by a second school bus.
The pickup driver and a 15-year-old student on one of the school buses were killed. Thirty-eight other people were injured in the Aug. 5, 2010, accident near Gray Summit, Mo.
Texting while driving has been identified as a scourge on U.S. roads by the Department of Transportation and several states, which have enacted anti-texting laws.
The National Highway Traffic Safety Administration (NHTSA) is currently evaluating proposed policy that could limit the communications technology that is allowed in passenger cars.
In the last few years the Feds have investigated a commuter rail accident that killed 25 people in California in which the train engineer was texting; a fatal marine accident in Philadelphia in which a tugboat pilot was talking on his cellphone and using a laptop; and a Northwest Airlines flight that flew more than 100 miles past its destination because both pilots were working on their laptops.
Read: Survey: Drivers Are Hypocrites When It Comes To Texting And Cellphone Use
"This is trending very hot and it's a growing concern for the NTSB," Hersman told The Associated Press.
The board has previously recommended bans on texting and cell phone use by commercial truck and bus drivers and beginning drivers, but it had previously stopped short of calling for a ban on the use of the devices by adults behind the wheel of passenger cars until Tuesday, when it recommended the ban be extended to all drivers.
The problem of texting while driving is getting worse despite a rush by states to ban the practice, Transportation Secretary Ray LaHood said last week. In November, Pennsylvania became the 35th state to forbid texting while driving.
About two out of 10 American drivers overall - and half of drivers between 21 and 24 - say they've thumbed messages or emailed from the driver's seat, according to a survey of more than 6,000 drivers by the National Highway Traffic Safety Administration.
For all the publicity about anti-texting laws, deaths attributed to distracted driving, the public remains ambivalent about limitations on in-car cell-phone and smart-phone use and harsh punishments when such behavior is tied to vehicular accidents.
Most U.S. motorists recently surveyed acknowledged few situations in which they would not use a cell phone or text while behind the wheel. Still, they support measures to curb both practices, data released early this month by the Department of Transportation (DOT) showed.
The findings were part of a study of driver behavior launched to help regulators understand "why some people continue to make bad decisions" about driving while distracted, officials said.
"What's clear from all of the information we have is that driver distraction continues to be a major problem," said David Strickland, the top U.S. auto safety regulator as head of NHTSA.
The survey results were released as Strickland's agency finalized traffic fatality figures showing 32,855 people were killed on U.S. roads in 2010, about 1,000 fewer than the 33,808 deaths in 2009.
The Associated Press contributed to this story.