The top US transportation safety body recommended Tuesday that all 50 US states impose a strict ban on the use of cellphones -- both hand-held and hands-free -- while driving.

"No email, no text, no update, no call is worth a human life," National Transportation Safety Board chief Deborah Hersman said in a conference call with reporters. "We have seen too many accidents as a result of distraction."

The NTSB recommendation does not carry the force of law but its decisions are generally given serious consideration by federal and state authorities.

"This is a watershed recommendation for the NTSB," Hersman said.

"We know our recommendation is not going to be very popular with some people," she said. "But we're not here to win a popularity contest."

The NTSB recommended that US states ban all non-emergency use of personal electronic devices (PEDs) while driving including hand-held cellphones and hands-free devices.

Hersman said it would be up to the states to determine the proper use of in-car devices such as GPS navigation systems.

"We do recognize that there are some technologies that can aid the driving task," she said.

The recommendation followed an investigation by the NTSB into a 2010 crash in Missouri in which a 19-year-old pickup driver who had been texting set off a chain-reaction collision that killed two people and injured 38.

In the August 5, 2010 accident, the pickup ran into the back of a truck that had slowed down because of road construction.

The pickup was rear-ended by a school bus which was then hit by another school bus. The pickup driver and a student on one of the buses died in the crash.

An NTSB probe revealed that the pickup driver had sent and received 11 text messages in the 11 minutes preceding the accident including one received just moments before striking the rear of the truck.

"While the Missouri accident is the most recent PED distraction crash the NTSB has investigated, it is by no means the first," the NTSB said, citing a number of other fatal accidents caused by distracted drivers.

Dozens of US states, including Missouri, already have laws banning texting while driving but the NTSB recommendation goes beyond current restrictions on cellphone use.

"This is a very difficult issue for us as a society," Hersman said. "But just like seat belts, smoking or drunk driving, it's about changing attitudes and changing the level of acceptance."

According to the US National Highway Traffic Safety Administration (NHTSA), there were more than 3,000 deaths in distraction-related accidents last year.

"The data is clear; the time to act is now," Hersman said.

"How many more lives will be lost before we, as a society, change our attitudes about the deadliness of distractions?" she asked.