Eddy, D., Patil, S., Krishnamurty, S., Grosse, I. et al., "Design and Evaluation of an Affordable Seatbelt Retrofit for Motor Coach Occupant Safety," SAE Technical Paper 2017-26-0018, 2017, doi:10.4271/2017-26-0018.
Prevention of passenger ejection from motor coach seats in the case of rollover and frontal crashes is critical for minimizing fatalities and injuries. This paper proposes a novel concept of affordably retrofitting 3-point seatbelts to protect passengers during these significant crash scenarios. Currently, the available options involve replacement of either the entire fleet, which takes time to avoid extremely high costs, or all seats with new seats that have seatbelts which is still expensive. Alternatively, this paper presents the development of an innovative product that can be installed in seat belt-ready bus structures at a fraction of the cost. The efficacy of the design is studied using finite element analysis (FEA) to meet Federal Motor Vehicle Safety Standards (FMVSS) 210 standards for conditions involved in frontal and side impacts. Similarly, the design’s effectiveness in rollover scenarios is studied using dynamic loading conditions in MAthematical DYnamic MOdeling (MADYMO) simulation software. The results from FEA and dynamic simulation studies are subsequently utilized to optimize the design for safety and comfort, as well as ease of maintenance and cleaning. The many salient features of the design include an optimized shape to maximize leg comfort and conformance to and clearance with many various seat configurations; a sliding guide on the shoulder belt webbing to accommodate different heights of the passengers; a provision for padded damping to enable rear occupant protection along with belt retractor enclosure; and optimal location of anchor points close to the seat to enable easy buckling of seatbelts and prevent slacking of seat belts during any crash.