WASHINGTON - The National Highway Traffic Safety Administration has put off by four months plans to publish a proposed rule that would require all new motorcoaches be equipped with lap-and-shoulder safety belts.

According to a posting on the U.S. Department of Transportation website, the rule will be published June 30 and the comment period will end two months later, Aug. 30

Initially, the rule was to have been published in February and the comment period was to have taken place in March and April. However, NHTSA said the dates had to be advanced because additional coordination was needed. It did not elaborate.

According to the posting, the rulemaking would amend Federal Motor Vehicle Safety Standard No. 208, "Occupant crash protection," to require the installation of three-point belts at all passenger and driving seating positions in newly manufactured motorcoaches.

Additionally, it would require the installation of lap-and-shoulder belts at driver seating positions of large school buses.

The posting made no mention of requirements that existing coaches be retrofitted with any type of safety belts, a mandate many motorcoach operators feared because of the high cost of adding the belts to their older coaches.

Estimates have ranged from $6,000 to $8,000 for seatbelts and $45,000 to $50,000 for retrofitted lap-and-shoulder belts.

NHTSA said the safety belt rulemaking is in response, in part, to recommendations made by the National Transportation Safety Board for improving bus safety. In addition, The USDOT in December unveiled an extensive new safety plan for the motorcoach industry that proposed seatbelts on new coaches.

Congress also has introduced bills involving seatbelts, including one that would mandate safety belts for motorcoaches and another that would require NHTSA to develop passenger restraint rules for coaches.

Although NHTSA declines to discuss its proposed rule in detail, the agency did say in a statement its committed to improving motorcoach safety.

"Thats why NHTSA expects to propose soon that seatbelts be required on motorcoaches to help prevent passenger ejections during a collision," it said. "The Department of Transportation also recently released its Motorcoach Safety Action Plan, which lays out concrete steps for addressing driver fatigue or inattention and improving operator maintenance."

The agency also stressed that safety is its No. 1 priority and it is committed to making sure bus travelers reach their destinations safely.

"In close coordination with Transportation Secretary Ray LaHood, NHTSA continues to actively work toward this goal," it added.

To read the posting, go to http://regs.dot.gov/rulemakings/201003/nhtsa.htm. The seat belt filing is No. 61.