A particular set of field data is analyzed in this report from the standpoint of contrast sensitivity. The scope of the analysis is of a preliminary nature. Several quantities are unknown at this time and only representative values are assumed. Some factors such as windscreen transmissibility are not considered since their inclusion would not change the basic nature of the results or the conclusions. The discussion is made under the following subheadings: detectability distances as derived from contrast thresholds, the effects of non-uniform surrounds in the visual environment, headlamp glare, transient adaptation, and field data analysis. Prior to the field experiments all drivers had participated in laboratory detection tests. They were fully aware of the target layout in the field and had a number of practice trails at each configuration. The nature of the experiment, that of obtaining upper and lower bounds of the detectability distance, constituted learning whenever a trial resulted in visible targets. It is therefore considered that the contrast multiplier associated with the field data is about 1.5.
Abstract