School Bus Visibility: Driver's Field of View and Performance of Mirror Systems on a Conventional Long-Nosed School Bus 980923

This report presents the results of the driver's field of view and the performance of six crossview and two sideview mirror systems on a conventional long-nosed school bus. It also contains an evaluation of the image quality of the crossview mirrors in terms of the angular length and width of their reflected images. The measurements of the field of view and the evaluation of image quality were done at two driver eye locations, one representative of the cyclopian view of a 95th percentile adult male and the other one representative of the cyclopian view of a 5th percentile adult female. Measurements were taken considering that there were no head movements. For the purposes of the study, the term “blind spot” was defined as meaning any area that could not be seen directly by the driver. The performance of the mirrors was judged in terms of their capacity to provide a complete and clear view of the blind spots.

The results demonstrated that none of the crossview mirrors on the conventional long-nosed bus performed adequately in that they did not eliminate the blind spots and provide good quality images to the front and sides of the bus. Furthermore, no crossview mirror reflected all the cylinders along the rear axle, and where they were viewed, the image quality was not always acceptable. The Double Nickel sideview mirror system, which is composed of one pair of flat and one pair of convex mirrors, had a narrower field of view than the mirrors installed by the bus manufacturer. Although the image quality of the sideview mirror systems was not formally evaluated, the Double Nickel had better image quality.

It should be noted that the results presented in this publication were extracted from a comprehensive school bus visibility study that was conducted by Transport Canada on four school bus configurations. In addition to the conventional long-nosed bus, the configurations included the flat-nosed bus, the short-nosed bus, and the minibus.