Targeted are intercity and tour buses with elevated passenger decks over a baggage compartment, said the federal agency on Nov. 16.

The NHTSA also called for stronger roofs to prevent passengers from being ejected in roll overs, electronic devices that monitor driver compliance with hours-of-service regulations, a federal prohibition on texting while driving, and limitations on driver cell-phone use.

National Transportation Safety Board Chairperson Deborah Hersman called the NHTSA proposal "a step forward.

"Any progress that can be made to protect passengers in all scenarios is an improvement that needs to be made," Hersman said in a talk at the National Press Club Nov. 16, following the NHTSA announcement. "It isn’t rocket science. Other countries have done it." 

Hersman also urged a federal regulation requiring use of shatterproof glass in buses, and called for greater federal efforts to curb fatigue among transportation workers in safety-sensitive positions.

She said the NTSB recommends the Federal Aviation Administration set hours-of-service rules for flight crews, aviation mechanics and air traffic controllers.

As for commercial bus and truck operators, Hersman said the Federal Motor Carrier Safety Administration has unsuccessfully attempted new driver hours-of-service rules three times since 2003, and plans another attempt at a new HOS rule in 2010.

It took Congress to change century-old rail employee hours-of-service rules, she said.