Section 16.24.030 Streets.

All streets shall conform to the principles and standards of design set forth in this section. The arrangement and character of all streets shall conform to the thoroughfare plan. Where necessary, additional right-of-way for widening, continuance or alignment as required in the thoroughfare plan shall be provided. Residential streets shall be designed to encourage traffic calming.

A. Pavement Construction.

1. Minimum requirements for pavement construction shall be in accordance with the standard detail drawings and standard specifications for the city, of current adoption, hereafter referred to as the "standard specifications," unless otherwise required by this chapter. A copy of the standard specifications is on file in the office of the engineering department.

2. The subdivider shall provide street pavements which shall be designed to carry the anticipated wheel loads and which conform with the standard specifications for rigid type pavement or flexible type pavement. In no event shall a concrete pavement be less than six inches of uniform thickness with a twenty-eight-day compressive strength of four thousand psi and six percent air entrainment. When determined necessary by the engineering department, four inches of stone sub-base may also be required. In no event shall a full depth asphaltic concrete pavement be less than six and one-half inches of uniform thickness. In no event shall an asphalt pavement with an untreated granular base consist of less than three inches of asphaltic concrete and seven inches of granular base.

3. Higher standards than indicated in subsection (A) (2) of this section may be required on those streets classified as collectors or higher by the thoroughfare ordinance. The higher standards may be specified to provide for unusual soil conditions, extraordinary traffic volume or other abnormal situations.

4. The subgrade for rigid and flexible pavement shall be prepared in compliance with standard specifications.

B. Connections. Streets shall be designed to provide connections between neighboring subdivisions. The commission shall require appropriate streets to be extended to the property boundary line to facilitate future connections. Land subdivided adjacent to tracts where such extensions have been made shall have street patterns which connect to these extensions. The right-of-way width for a new street that is a continuation of an existing street shall in no case be continued at a width less than that of the existing street. The creation of reserve strips shall not be permitted adjacent to a proposed street in such a manner as to deny access from adjacent property to the street.

C. Half-Streets. Dedication on new half-streets shall not be permitted. Where a dedicated or platted half-street is adjacent to a tract being subdivided, the other half of the half-street shall be platted and constructed.

D. Dead-End Streets. Permanent dead-end streets shall not be permitted. Temporary dead-end streets with temporary turn-arounds shall be permitted only as part of a continuing street plan.

E. Alleys. Alleys may be developed as secondary access to lots, particularly in high-density areas. Where permitted, they shall be designed to discourage through traffic, and no parking shall be allowed within the alley. Alleys shall be designed to accommodate refuse disposal vehicles, including adequate turning radii and turnaround. Alleys shall have twenty feet of right-of-way width and twelve feet of pavement width.

F. Major Intersections. When subdivision streets intersect with collector or arterial streets, the subdivider may be required to install deceleration and passing lanes or other improvements along the major street.

G. Minimum Design Standards for Streets. (See Table I at the end of this section.)

H. Intersection Design Standards. (See Table II at the end of this section.)

I. Vertical Alignment. All changes of grade shall be connected by vertical curves of a minimum length equivalent to eighty-five times the algebraic difference in the rate of grade, expressed in feet per hundred, for arterial streets; fifty-five times the algebraic difference for collector streets, and thirty-five times the algebraic difference for local and other minor streets. In no case though, shall the minimum length of the vertical curve be less than one hundred eighty feet for arterial, one hundred twenty feet for collector, and ninety feet for local or minor street.

J. Access Standards. Access from streets to abutting property shall be limited to the standards shown in Table III at the end of this section.

TABLE I

PUBLIC STREET DESIGN STANDARDS

STREET TYPE


	Design Criteria	Cul-De-Sac and Marginal Access	Local Streets	Collector Streets	Arterial Streets

1.	Design Speed, mph	N.A.	30 mph	40 mph	50 mph
2.	Right-of-way	50 ft.	50 ft.	70 ft.	(See Note 2)
3.	Pavement width w/curb	30 ft.	30 ft.	40 ft.	(See Note 3)
4.	Sidewalk width	4 ft.	4 ft.	5 ft.	5 ft.
5.	Minimum horizontal visibility (See Note 4)	150 ft.	150 ft.	275 ft.	350 ft.
6.	Maximum grade	10%	8%	7%	6%
7.	Minimum grade	0.3%	0.3%	0.3%	0.3%
8.	Minimum tangent length for reversed curve	0 ft.	50 ft.	100 ft.	200 ft.
9.	Minimum radius of curvature (See Note 5)	150 ft.	200 ft.	300 ft.	775 ft.
10.	Maximum super-elevation rate	Normal crown	Normal crown	0.06 ft./ft.	0.08 ft./ft.

Note 1:

Cul-de-sac: maximum length = 1000 ft. or 15 potential dwelling units.

Note 2:	Right-of-way:	Expressway arterial	-	160 ft. (120 ft.w/full access control)
		Primary arterial	-	90 ft.
		Secondary arterial	-	80 ft.
		One-way arterial	-	60 ft.
Note 3:	To be determined by commission.

Note 4:	Measured at the centerline of inside travel lane with an eye height of 3.75 ft. and object height of 0.5 ft.
Note 5:	If horizontal alignment change exceeds 75 ° , the street may be designed as an intersection with 2 approaches using the intersection design standards set forth in Table II.

TABLE II

INTERSECTION DESIGN STANDARDS

	Criteria		Standards

1.	Maximum approach speed		25 mph

2.	Vertical alignment at an intersection or railroad		1/2 maximum grade w/in 200' of intersection

3.	Angle of intersection		90 ° preferred; 75 ° minimum

4.	Minimum curb radius:	local-local	25 ft.
		local-collector	25 ft.
		collector-collector	30 ft.

5.	Minimum centerline offset between cross type intersections:

		local-local	200 ft. (See Note 1)
		local-collector	300 ft. (See Note 2)
		collector-collector	600 ft. (See Note 3)
		collector-arterial	1320 ft.

6.	Maximum number of roads at intersection		2 streets (4 approaches)

Note 1: Or 150 ft. between opposing T-type intersections

Note 2: Or 200 ft. between opposing T-type intersections

Note 3: Or 300 ft. between opposing T-type intersections

TABLE III

ACCESS STANDARDS

Street Type

Minimum Distance Between Drivers or to Nearest Intersection


	Commercial Drive	Residential Drive

Arterial	600'	Not permitted
Collector	200'	200*
Local	100'	One per lot

* Site plan must call for turn around space so that vehicles will not back directly onto right-of-way.

(Ord. 99-24 § 3 (part), 1999; prior code § 28-39)