The University of Massachusetts Amherst
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Retrofit Seat Belt System Seeks to Make Travel Safer on Thousands of Motor Coaches

Retrofit Seat Belt

Seat Belt

Researchers at the University of Massachusetts Amherst College of Engineering have designed an invention that would make it feasible, practical, and economical to install life-saving seat belts on some 30,000 motor coaches nationwide that venture on the road without seat belts.

The National Science Foundation Innovation Corps (I-Corps) recently awarded $50,000 to a research team led by Principal Investigator Sundar Krishnamurty of the UMass Amherst Mechanical and Industrial Engineering (MIE) Department to help commercialize a patent-pending “Retrofit Seat Belt System” and make buses everywhere safer for travelers. The I-Corps program aims to prepare scientists and engineers to extend their focus beyond the laboratory and broadens the impact of select NSF-funded projects.

Krishnamurty says that “Our seat belt is designed to meet federal standard FMVSS 210 and presents the most viable option to retrofit seat belts in motor coaches that do not have them.”


The problem is that, though all new motor coaches manufactured after 2015 will be required to have seat belts, only about 20 percent of the existing buses have the safety devices, according to the 2013 Motor Coach Census. The Department of Transportation Motor Coach Safety Action Plan of 2009 demonstrates that seat belts with lap and shoulder straps in motor coaches can save countless lives. For example, seat belts could reduce the risk of fatal injuries by 77 percent in rollover crashes, primarily by preventing occupant ejection on impact.


But motor coach companies are not currently obligated by law to install safety belts in their existing buses because of the high cost, which is cited by the National Highway Traffic Safety Administration Final Rule of 2013 as the one obstacle to a requirement that bus companies must retrofit existing motor coaches with seat belts.

The Retrofit Seat Belt System would remove that obstacle. Estimates indicate that it now costs about $40,000 per motor coach to add lap and shoulder belts to all seats, which is considered beyond the means of bus owners. By comparison, Krishnamurty’s team estimates that implementing the Retrofit Seat Belt System should cost less than $10,000 per motor coach.

Krishnamurty notes that “This design is affordable because it is the only known way to add seat belts to existing motor coaches without replacement of all the seats. Furthermore, it will be minimally intrusive and noticeable to passengers. Thus, we can expect many bus owners to be interested in a more profitable means to improve the critical safety and comfort of their passengers.”

“Our expectation is that some owners will decide to retrofit pre-2016 buses with seat belts as time goes on and their customers become accustomed to and comfortable with wearing seat belts and thus may choose bus carriers based on the availability of seat belts,” says the research team’s Co-Principal Investigator, John Collura, the Associate Dean for Research and Innovation in the College of Engineering and the Director of the University of Massachusetts Transportation Center.

The research team’s partnership with Peter Pan Bus Lines is concrete evidence of keen interest by motor coach companies in the Retrofit Seat Belt System. Michael Sharff, who has worked in the bus industry for more than 30 years and currently serves as the Director of Planning and Development for Peter Pan Bus Lines and General Manager of Peter Pan Transportation Services, is one of the four members of Krishnamurty’s research team.

“The federal government requirement to purchase new buses with seatbelts takes effect in 2016,” says Sharff. “In advance of this law, Peter Pan started ordering new buses with 3-point seatbelts in 2009, the first year they were available. We and many in the bus industry have a number of buses built before 2009 without belts. We had been told by some manufacturers that a retrofit of belts on existing seats and floor anchoring was not possible. The development of a belt retrofit program by the UMass team is a huge development in advancing safety and security of bus passengers, and I expect great interest in this program by the industry.”

The fourth member is entrepreneurial lead Douglas Eddy, the Co-Site-Director of the Center for e-Design and a post-doctoral researcher in the MIE department at UMass Amherst. In response to the widespread problem of older buses without seat belts, Krishnamurty collaborated with Eddy to co-invent the patent-pending Retrofit Seat Belt System, calling it an “economical and customizable” design for equipping existing buses with safety belts.  

The inventors observe that their Retrofit Seat Belt Design “is unique, novel, nonobvious, useful, and different from all existing patents and products.”

First of all, it has the singular feature of adequate structural support for the lap and shoulder belts. Some or all of the loads are shared by the added center support structure connected rigidly to the floor via a base plate, and the design facilitates a seamless transition for the different seat configurations of motor coaches. Based on the design and condition of the motor coach seats, the strength of the center support can be individually customized to support the seat belt design, while maintaining the integrity of the existing bus frame structure.

“This invention can be expected to be universal and economical,” conclude the researchers.
“It is great to see that this valuable research is continuing to break new ground in the area of improving highway safety,” says Michael Knodler, Director of the MassSafe traffic safety research program at UMass Amherst. “The NSF I-Corps funding builds on the crashworthiness testing conducted with USDOT research funds that UMass received over the last several years through the New England University Transportation Center administered by MIT.” (September 2015)