The US National Highway Traffic Safety Administration (NHTSA) has proposed structural design changes to motorcoaches to ensure passenger safety during accidents.

According to the standards, manufacturers are required to design large buses so that the space around the passengers remains sufficiently intact and the emergency exits remain operable if the vehicle overturns.

The NHTSA’s proposal requires space around occupant seating positions to be maintained to afford occupants a survivable space in a crash.

"Stronger large bus structures, combined with seat belt use, will help keep passengers secured and protected in the event of a crash."

The agency will conduct tests to ensure the buses meet the required standards, which have been based on European regulations.

The seats, overhead luggage racks and window glazing need to remain attached to their mountings during and after the test, while emergency exits need to stay closed during the rollover test and be operable afterwards.

NHTSA acting administrator David Friedman said: "Stronger large bus structures, combined with seat belt use, will help keep passengers secured and protected in the event of a crash."

The standards are a prelude to a separate proposal that envisages stability control technologies in vehicles to prevent them from rollovers. The proposal is likely to be made later this year.

Federal Motor Carrier Safety Administration administrator Anne Ferro said: "In addition to taking critical steps to improve the structural design of buses, we are committed to further increasing motorcoach safety through stricter oversight, in-depth investigations into high-risk companies and by ensuring that drivers are properly licensed and medically fit for the job."