Primary design factors with regard to outside mirrors are curvature, size and spatial localization. Experiments were conducted to find the effects of these factors in relation to visibility and the size of field of view. Investigations to determine visibility requirements were static testing and field testing. The results show that convex mirrors with 47 inch radius of curvature are most preferable for the visibility requirements. Required size of field of view was established taking into account the size of direct field, vehicle size and lateral distance to another car.