In this study the subgroup concentrated on the windshield, the major factor in driver forward visibility. Certain areas of the windshield are used more frequently than others in traffic situations to observe signal lights, traffic signs, street markings, other traffic and pedestrians. These are defined as the areas of primary forward driver visibility.

This study was limited to passenger cars. Variations in configuration and driver operating conditions indicate desirability of a separate and later study for trucks and buses.