Technology has provided drivers with in-vehicle information systems (INVIS) that can make driving more pleasurable but at the same time more complex in sharing visual attention. The purpose of this study was to evaluate the use of the useful field of view (UFOV) as a tool for developing driver visual attention and visual processing aids by automobile and INVIS designers. We expressed UFOV as a function of saccadic amplitude between fixation points and durations and evaluated it across different driving scenarios and age groups. Our results suggest that UFOV radius depends on driving scenario, time of event, and age, with two-factor and three-factor interactions among these variables. Based on these results suggestions are made that will aid designers in developing better in-vehicle information systems - scenario information that may otherwise be missed by older drivers.