If the project involves existing drives, the existing width is normally retained
unless it is less than 12 ft (3.7 m). In that case, it should be widened to provide a 12-ft
(3.7-m) throat width. In the case of new drives, the width should normally be 12 ft (3.7 m).
If the new driveway is a combined drive between two properties, the width should normally
not exceed 24 ft (7.3 m). Also, a wider field drive may be used if it will keep a
farm equipment operator from encroaching on the opposing traffic lane when entering
or exiting the highway.