Contra Costa County Municipal Code Ch. 98-6 Grades

Maximum street grades shall not exceed the following limits:

(1) Arterial streets, eight percent;

(2) Collector streets, fifteen percent;

(3) Minor streets, twenty percent;

(4) Private road, twenty percent;

(5) Driveway, twenty-five percent.

(Ord. 78-5).

The minimum uniform grade for all classes of streets shall not be less than one percent, except reduction to not less than one-half of one percent may be authorized by the public works department.

(Ord. 78-5).

The grade of the pavement surface across an intersection shall not be more than six percent.

(Ord. 78-5).

The centerline grade of each street entering an intersection shall not be more than six percent within a distance of thirty feet from the nearest curbline of the intersected street.

(Ord. 78-5).

Changes of grade in vertical alignment of streets shall be made with parabolic vertical curves. The design of such curves shall be in accordance with standards outlined in the California Division of Highways "Highway Design Manual."

(a) "Stopping sight distance" shall be provided for the following design speeds:

(1) Arterial and industrial streets, forty miles per hour;

(2) Collector streets, thirty miles per hour;

(3) Minor streets, twenty miles per hour;

(4) Private roads, fifteen miles per hour.

(b) "Headlight sight distance" shall be provided for sag vertical curves in accordance with these requirements, except where installation of street lights eliminates any sight restriction due to lighting.

(Ord. 78-5).

The minimum length of a vertical curve shall be fifty feet for minor streets and private roads, one hundred feet for collector streets, and two hundred feet for arterials.

(Ord. 78-5).

Earth slopes in cuts or embankment sections shall not be steeper than one and one-half feet horizontal to one foot vertical, unless steeper slopes have been approved based on a report submitted by a soil engineer. The soil report shall be filed with the public works department.

(Ord. 78-5).

(a) Changes in direction of the streets shall be made with horizontal circular curves, with the edges of the pavement and curblines parallel to and equidistant from the centerline of the right-of-way.

(b) The radius of curvature in the centerline of the street shall not be less than:

(1) Arterial street, six hundred fifty feet;

(2) Collector street, two hundred feet;

(3) Minor street, seventy-five feet;

(4) Private road, twenty-five feet.

(Ord. 78-5).