Describing and Evaluating the Truck Driver's Viewing Environment J1750_201010

DOI: https://doi.org/10.4271/J1750_201010

Issuing Committee: Truck and Bus Human Factors Committee

Publisher: SAE International

Pages: 29

Rationale: The 1995 version of this SAE Recommended Practice presented only two methods of evaluation: the Polar Plot and the Horizontal Planar Projection. Each of these methods is insufficient to adequately describe both direct and indirect fields of view around the entirety of the vehicle. However, the document referenced additional “experimental and graphical methods” that were defined at the time as beyond the scope of the document. This release is intended not to replace methods originally presented, and rather adds the preferred Target Evaluation, which allows for utilization of available tools that complete the original purpose of this Recommended Practice. The Target Evaluation Method may be utilized for alternative vision systems as well (i.e., cameras and monitors), but additional work is necessary to specify system requirements that appropriately consider valid image representation (clarity, acuity, distortion, size, etc.). A minimum mirror radius of 300 mm for a spherical convex mirror is recommended based on a consensus of the committee. Appendix D describes the rational for this limit which is derived from considerations of visual acuity and typical vehicle layout. In establishing a Target Evaluation Procedure, care was taken to ensure that the evaluation could be conducted in a simulated environment with appropriate CAD utilization, or equivalently with manual methods. This procedure details target cylinders and spacing, which were selected to be similar to the concept established in the Federal Regulation FMVSS 111, as required for school buses, with notable improvements. Within the Target Evaluation Method, it is acknowledged that the extrapolation of the solid angles to form a vision cone, are not fully detailed in this Procedure with consideration of ergonomic limitations (i.e., head and eye movement). These limitations should be considered, but as with the previous 1995 version, are beyond the scope of this document. It is recognized that the Target Evaluation Procedure counts the cylinder targets on the boundary between zones twice but it was judged by the Task Force to be preferable over a more complicated procedure that attempted to resolve the double count. This resolution of boundary target cylinders also allows each zone to be assessed independently, as well as in summary, to achieve a field of view volume evaluation. The Target Evaluation Procedure requires a setup with the mirrors in the nominal adjustment position. The Task Force intended to require that both the top and bottom corners of the extremities of the vehicle would be visible, but it was determined that in most situations these extremities could not be viewed simultaneously without adjusting the mirror surface from nominal. Therefore, the bottom extremities of the vehicle were chosen as required view points.