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https://nap.nationalacademies.org/catalog/27432/critical-issues-in-transportation-for-2024-and-beyond

Measurement of School Bus Pedal Dimensions

The National Transportation Safety Board (NTSB) investigated four crashes of school buses and one of a fire truck, all of which occurred from 2005 to 2009 and concluded that these accidents were consistent with pedal misapplication. Among the NTSB recommendations was that the National Highway Traffic Safety Administration (NHTSA) analyze pedal configurations in heavy vehicles to determine the effect of pedal design on the driver’s task. This research was performed at NHTSA’s Vehicle Research and Test Center (VRTC), in East Liberty, Ohio, to provide an overview of the range of typical pedal dimensions in school buses. However, analysis to determine the effect of pedal design on the driver’s task was beyond the scope of this study. NHTSA identified 21 dimensions based on the SAE J1100 standard and also developed a procedure capable of determining pedal position. Two additional dimensions were used for the analysis of the transit style buses to account for the steering column position. The dimensions for 24 Type C (conventional style) buses and 8 Type D (transit style) buses were measured and compared. Only the stepover distance, the seat cushion width, and the steering wheel width and height were not significantly different between the two types. The Type C buses measured were assembled by three different manufacturers, Bluebird Corporation, Fort Valley, GA; IC Corporation, Warrenville, IL (a subsidiary of Navistar); and Thomas Built Corporation, High Point, NC (a subsidiary of Daimler Trucks, N.A.). The Bluebird and Thomas Built buses were the most similar, but they had statistically significant differences in the brake pedal width and the stepover distance from the face planes of the pedals, as well as some differences in seating position. The IC buses were statistically different in 11 and 12 of 21 measurements from the Bluebird and Thomas Built buses, respectively. The dimensions for six Type D buses manufactured by Bluebird and two by Thomas were measured. The dimensions were statistically different in only 8 of the 23 dimension measured. Most of the differences were smaller distances from the pedals to the “tunnel” on the right side of the pedals for the Bluebird buses. The measurements for the 32 buses were compared to the dimensions of 101 passenger vehicles. Seventeen of the 21 dimensions were statistically different. Even though the means were different, the distributions of values had considerable overlap. The variables that had little overlap were that the bus accelerator and brake pedals had a shorter overall travel to the floor, and the steering wheel was farther from the floor and pedals for buses than for the passenger vehicles. The dimensions of both the Type C and Type D buses were compared to the average dimensions of the passenger cars. The measurements of Type D buses differed from passenger cars in nearly every dimension. Only the distance from the accelerator to the tunnel and the seat cushion width were not significantly different, and for 14 of the dimensions there was no overlap between the outliers of the 2 distributions. The Type C buses were more similar to passenger car dimensions, differing in 10 of the 21 dimensions measured, with only the height and size of the steering wheel having no overlap between the distributions.

Language

  • English

Media Info

  • Media Type: Digital/other
  • Features: Appendices; Figures; Photos; References; Tables;
  • Pagination: 181p

Subject/Index Terms

Filing Info

  • Accession Number: 01574121
  • Record Type: Publication
  • Report/Paper Numbers: DOT HS 812 168
  • Files: HSL, TRIS, ATRI, USDOT
  • Created Date: Aug 27 2015 11:28AM