a. Arterial and collector streets shall be limited to a maximum grade of ten percent (10%). Sustained grades (six hundred feet (600') or more) shall be limited to seven percent (7%).

b. Local residential streets shall be limited to maximum grade of twelve percent (12%). Sustained grades (six hundred feet (600') or more) shall be limited to nine percent (9%).

c. Cul-de-sacs with a negative grade progressing toward the turnaround shall be limited to a maximum grade of six percent (6%). The cul-de-sac shall terminate with a grade not to exceed three percent (3%) for the last one hundred feet (100') of traveled surface. The cul-de-sac shall be limited to a maximum length of six hundred fifty feet (650') and have adequate easement for drainage.

d. Street intersections shall have a vertical alignment such that the centerline grade shall not exceed three percent (3%) for a minimum distance of fifty feet (50') each way from the centerline of the intersection.

e. Maximum grades shall be approved only when accompanied by changes to a lesser grade, and where length of that portion of that road at maximum grade is less than six hundred feet (600').

f. All changes in vertical alignment shall be made by vertical curves with minimum length of one hundred feet (100') for minor streets and three hundred feet (300') for major streets. Actual vertical curve length shall be a function of design speed.

g. Streets in mountainous terrain shall be designed at less than maximum allowable grade in order that they can be safely negotiated and that snow can be removed during winter.

a. To facilitate the construction of essential and vital public infrastructure;

b. To facilitate the development of private property when street grade requirements would render the property undevelopable because of topographic conditions, and conditions are present or measures are proposed that would acceptably mitigate the negative effects of the steeper grades.