Chapter 18.12 STREETS

Chapter 18.12
STREETS

Sections:

Article I. Street Design

18.12.010 Street section design.

18.12.020 Subgrade evaluation.

18.12.030 Structural section.

18.12.040 Horizontal alignment.

18.12.050 Vertical alignment.

18.12.060 Intersection sight distance policy.

18.12.070 Angles between intersecting streets.

18.12.080 Cul-de-sacs, eyebrows, turnarounds.

18.12.090 Driveway approaches.

18.12.100 Curbs and grading.

18.12.110 Sidewalks and clustered mailboxes.

18.12.120 Guardrails.

18.12.130 Transitions.

18.12.140 Superelevation cross-sections.

18.12.150 Stub streets.

18.12.160 Private streets, parking lots, and common driveways.

18.12.170 Utilities.

18.12.190 Temporary parklets – In on-street parking spaces.

Article I. Street Design

18.12.010 Street section design.

All street sections shall be designed by the engineer or a geotechnical engineer based on the on-site soil conditions and shall meet the minimum standards as outlined in SHMC 18.12.030. (Ord. 2875 Appx. § 210.1, 2003)

18.12.020 Subgrade evaluation.

Soil testing to obtain the strength of the soil may be required in order to analyze and design the structural section for streets and roads. Soil tests are needed on undisturbed samples of the subgrade materials that are expected to be within three feet of the planned subgrade elevation. Samples are needed for each 500 feet of roadway and for each visually observed soil type. Soil tests are required from a minimum of three locations.

The selected design structural strength of the soil needs to be consistent with the subgrade compaction requirements. The strength and compaction moisture content, at optimum to slightly over optimum, needs to be specified. The soils report shall address subgrade drainage and ground water considerations for year-round conditions. Recommendations for both summer and winter construction shall be included. The required density of treated and untreated subgrade materials shall not be less than 95 percent maximum density as determined by AASHTO T-99. (Ord. 2875 Appx. § 210.2, 2003)

18.12.030 Structural section.

(1) Streets may be constructed of the following:

(a) Full depth asphaltic concrete.

(b) Asphaltic concrete with crushed rock base or treated bases.

(2) Aggregate Base. All aggregate shall meet OSHD specifications for base rock.

The minimum aggregate section, unless otherwise approved by the city engineer, shall be an eight-inch base course of one-and-one-half-inch to zero-inch with a two-inch leveling course of three-fourths-inch to zero-inch. This equals a total minimum section of 10 inches of aggregate.

During compaction, materials shall be maintained within two percent of the optimum moisture content. The contractor shall begin compaction of each layer immediately after the material is spread, and continue until a density of not less than 95 percent of the maximum density has been achieved. Maximum density will be determined by AASHTO T-180, or OSHD TM-106.

(3) Asphalt Pavement Design. If asphalt pavement is to be placed in a single lift, the wearing course shall be no less than three inches of OSHD Class “C.”

If asphalt pavement is to be placed in two lifts, the street section including the aggregate base and first lift of AC pavement must be designed to support the loads expected throughout all construction and/or building phase(s) until permanent wearing course is installed. The base course of asphalt concrete (AC) streets may be a minimum of two inches of OSHD Class “B” or Class “C” and the wearing course shall be one and one-half inches of OSHD Class “C” for a total minimum thickness of three and one-half inches in two lifts. For asphalt thickness greater than three and one-half inches, the Oregon Standard Specifications for Construction guidelines shall be followed.

The compaction shall be at least 91 percent based on a Rice theoretical maximum density, as determined in conformance with AASHTO T-209, as modified by OSHD.

Asphalt pavement may be designed using any nationally recognized procedure; both the OSHD and the Asphalt Institute methods are discussed below:

(a) Oregon State Highway Division Method.

(i) Test the soil to determine the R-value by AASHTO T-190.

(ii) Determine the 18 kip equivalent axle load (EAL) constant. Use a traffic analysis worksheet (see Figure 2-1) to calculate 18 kip EAL and the traffic coefficient. The two-way traffic should be based on vehicle classification counts and functional classification of the street. The expansion factor for a 20-year period and the daily traffic for each project shall be determined by a traffic study or provided by the city.

(iii) Calculate the total structural thickness for the roadway section in terms of the crushed aggregate base. This is the crushed base equivalent in inches (CBE).

CBE = 0.03546 (TC) (100-R)

(iv) Choose the structural section for the street using Table IIa.

(b) Asphalt Institute Method. Design of asphalt concrete pavement structures by this method shall conform to the guidelines of the Asphalt Institute publication, “Thickness Design – Asphalt Pavements for Highways and Streets, Manual Series No. I.”

(i) AASHTO T-193 (CBR Method); or

(ii) AASHTO T-190 (R-Value Method); or

If the CBR value of the subgrade exceeds 20 or the R-value of the subgrade exceeds 60 then CBR and R-value methods shall not be used.

(4) Design Example.

AC STRUCTURAL SECTIONS EXAMPLE (OSHD METHOD)
FIND:	STRUCTURAL SECTION (Asphaltic Concrete)
Given:	24-HOUR TRAFFIC MIX (90 2-axle trucks, 45 3-axle trucks, 5 4-axle trucks, 90 5-axle trucks, 0 6-axle trucks)
R = 6	(OSHD Method)
STEP I.	Complete the traffic analysis worksheet, Figure 2-1, as shown in Figure 2-2
STEP II.	TC = 8.9 (from Step I)
STEP III.	Go to Table II, with R = 6, and TC = 8.9, find CBE = 28.2″
STEP IV.	Using CBE factors from Table II, go to CBE factors Table II and find that:

Alternative I
4-inch AC x 2 =	8.0-inch CBE
2-inch 3/4-inch-0 x 0.8 =	1.6-inch CBE
11-inch CTB x 1.8 =	19.8-inch CBE
	29.4-inch CBE

or we find an alternate structural section could be:

Alternate II
8-inch AC x 2 =	16.0-inch CBE
2-inch 3/4-inch-0 x 0.8 =	1.6-inch CBE
14-inch 2-inch-0 x 0.8 =	11.2-inch CBE
	28.8-inch CBE

FIGURE 2-1 TRAFFIC ANALYSIS WORKSHEET
PRESENT ADT:	__________	STREET:	__________
PRESENT NUMBER OF:		FROM:	__________
2-Axle trucks	__________	TO:	__________
3-Axle trucks	__________
4-Axle trucks	__________	D = B x C
5-Axle trucks	__________	E = B + D
6-Axle trucks	__________	2
		F = One-Way Annual
		G = E x F
		TC = 9 x (20-Year 18 kip EAL) 0.119
		1,000,000


A	B	C	D	E	F	G
2		1.48			36.5
3		1.48			119.5
4		1.48			157.0
5		1.48			296.0
6		1.48			325.0


TOTAL – AVG. ANNUAL 18 kip EAL =	___________
18 kip EAL/day =	___________
20-Year 18 kip EAL =	___________
Traffic Coefficient, TC =	___________

FIGURE 2-2 – TRAFFIC ANALYSIS WORKSHEET (EXAMPLE)
PRESENT ADT:	3800	STREET:	A Street
PRESENT NUMBER OF:		FROM:	X Road
2-Axle trucks	90	TO:	Y Road
3-Axle trucks	45
4-Axle trucks	5	D = B x C
5-Axle trucks	90	E = B + D
6-Axle trucks	0	2
18 kip EAL		F = One-Way Annual
		G = E x F
TC = 9 x (20-Year 18 kip EAL) 0.119
1,000,000


A	B	C	D	E	F	G
2	90	1.48	133.2	111.6	36.5	4,073.4
3	45	1.48	66.6	55.8	119.5	6,668.1
4	5	1.48	7.4	6.2	157.0	973.4
5	90	1.48	133.2	111.6	296.0	33,033.6
6	0	1.48	0	0	325.0	0

						44,748.5


TOTAL – AVG. ANNUAL 18 kip EAL	= 44,748.5
18 kip EAL/day	= 122.6
20-Year 18 kip EAL	= 894,970.0
Traffic Coefficient, TC	= 8.9

TABLE IIa – CRUSHED BASE EQUIVALENT ALL ROADS
MINIMUM TRAFFIC COEFFICIENT	R=4 MIN. “CBE” REQRMNT	R=8 MIN. “CBE” REQRMNT	R=12 MIN. “CBE” REQRMNT	R=18 MIN. “CBE” REQRMNT	R=22 MIN. “CBE” REQRMNT	R=26 MIN. “CBE” REQRMNT	R=30 MIN. “CBE” REQRMNT
12.0 – 13.0	42.5″	41.0″	39.0″	36.5″	34.5″	33.0″	31.0″
11.0 – 12.0	39.0″	37.5″	36.0″	33.5″	32.0″	30.0″	28.5″
10.0 – 11.0	36.0″	34.5″	33.0″	30.5″	29.0″	27.5″	26.0″
9.0 – 10.0	32.5″	31.0″	29.5″	27.5″	26.5″	25.0″	24.0″
8.0 – 9.0	29.0″	27.5″	26.5″	24.5″	23.5″	22.5″	21.0″
7.0 – 8.0	25.5″	24.5″	23.5″	22.0″	21.0″	20.0″	18.5″
6.0 – 7.0	22.0″	21.0″	20.0″	19.0″	18.0″	17.0″	16.0″
4.8 – 6.0	18.5″	17.5″	17.0″	15.5″	15.0″	14.0″	13.5″
Below 4.8	16.5″	15.5″	15.0″	14.0″	13.5″	12.5″	12.0″


CBE FACTORS
1.0″ Asphaltic Concrete Wearing Surface or Base	=2.0″ Aggregate Base
1.0″ Emulsion Treated Wearing Surface or Base	=2.0″ Aggregate Base
1.0″ Cement Treated Base*	=1.8″ Aggregate Base
1.0″ Plant Mix Bituminous Base	=1.8″ Aggregate Base
1.0″ Oil Mat	=1.8″ Aggregate Base
1.0″ Cement Treated Existing Roadway Material	=1.5″ Aggregate Base
1.0″ Lime or Cement Treated Subgrade	=1.0″ Aggregate Base
1.0″ Aggregate Subbase	=0.8″ Aggregate Base

Above factors apply to materials that comply with Columbia County standard specifications and special provisions.

Use fabric mat where moisture is present in the subgrade, or use fabric mat plus excavate an additional 12 inches and replace with rock for unusually wet subgrade conditions.

* Lime treated base is to be considered to have the same aggregate base equivalent as cement treated base (1.8 inch).

(5) Portland Cement Concrete Pavement. The design of Portland cement concrete streets shall be governed by the guidelines and requirements of the Portland Cement Association (PCA) design procedures found in the below-listed publications:

“Concrete Streets: Typical Pavement Sections and Jointing Details.” Portland Cement Association (1S211.01P), Skokie, Illinois: 1980.

“Thickness Design for Concrete Highway and Street Pavements.” Portland Cement Association (EB109.01P), U.S.A.: 1984, p.7.

“Joint Design for Concrete Highway and Street Pavements.” Portland Cement Association (1S059.03P), Skokie, Illinois: 1980.

(a) All field testing shall follow ACI and OSHD procedures.

(b) All other design criteria shall follow ACI and the Oregon Standard Specifications for Construction, including revisions. (Ord. 2875 Appx. § 210.3, 2003)

18.12.040 Horizontal alignment.

(1) Alignments shall meet the following requirements:

(a) Centerline alignment of improvements should follow the centerline of the right-of-way. If this is not practical, then the alignment should parallel the centerline of the right-of-way.

(b) Centerline of a proposed street extension shall be aligned with the existing street centerline.

(d) Reversing horizontal curves shall be separated by no less than 50 feet of tangent, unless otherwise approved by the city engineer. On arterials, the separation shall be no less than 100 feet.

TABLE IIb – CENTERLINE RADIUS – MINIMUMS
Minimum Centerline Radii
Street Classification	Minimum Radius, Ft.
Arterials	300
Collectors	200
All Other Classifications	100

(2) Monumentation. Monuments shall be set in accordance with the standard details. See SHMC 17.140.110 (centerline monumentation).

Centerline monuments shall be set at the PI if it falls within the paved section of roadway. If the PI falls outside of the paved section, then the PC and PT of the curve shall be monumented. On tangent sections where sight between monuments is not possible, a POT shall be set. All intersections shall be monumented including intersections of the project on existing roadways. These monuments shall be set at the intersection of the surveyed right-of-way centerlines. (Ord. 2875 Appx. § 210.4, 2003)

18.12.050 Vertical alignment.

Alignments shall meet the following requirements:

(1) Minimum tangent street gradients shall be one-half percent along the crown and curb.

(2) Maximum street gradients shall be six percent for arterials, 10 percent for collectors, and 12 percent for all other streets. Grades in excess of 12 percent may be allowed on local or residential streets for short segments of no greater than 250 feet as approved by the city engineer. In no case shall grades be allowed to exceed the State Fire Marshal’s maximum grade guidelines.

(3) Local streets intersecting with a minor collector or greater functional classification street or streets intended to be posted with a stop sign shall provide a landing averaging five percent or less. Landings are that portion of the street within 20 feet of the projected curb line of the intersecting street at full improvement.

(4) Grade changes of more than one percent shall be accomplished with vertical curves.

(5) At street intersections, the crown of the major (higher classification) street shall continue through the intersection. The roadway section of the minor street will flatten to match the longitudinal grade of the major street at the projected curb line.

(6) Street grades, intersections, and superelevation transitions shall be designed to not allow concentrations of storm water to flow across the travel lanes.

(7) Streets other than arterials shall be constructed with a minimum crown of two percent from the centerline to the flow line, and a maximum crown of three percent, unless otherwise approved by the city engineer.

(8) Offset crowns shall be allowed only with the specific prior approval of the city engineer and must conform to the standard drawing for offset crowns.

(9) Slope easements shall be dedicated or obtained for the purposes of grading outside of the right-of-way.

(10) Streets intersected by streets not constructed to full urban standards shall be designed to match both present and future (as far as practicable) vertical alignments of the intersecting street. The requirements of this title shall be met for both present and future conditions.

(11) Curbs shall be placed as monolithic curb and gutter unless otherwise approved by the city engineer.

When new streets are built adjacent to or crossing drainageways, the following standards shall govern the vertical alignment:


Functional Classification	Vertical Standard
Principal routes and arterials	Travel lanes at or above the 100-year flood elevation.
Major collectors	Travel lanes at or above the 50-year flood elevation but not lower than six inches below the 100-year flood elevation.
Minor collectors and local streets (residential)	Travel lanes at or above the 25-year flood elevation but not lower than six inches below the 100-year flood elevation.
Local streets (nonresidential)	Travel lanes at or above the 25-year flood elevation but not lower than six inches below the 50-year flood elevation.

If alternate access is available for properties served by a particular local street, a design could be considered for approval by the city engineer that would set the travel lanes at or above the 10-year flood elevation but not lower than six inches below the 25-year flood event.

Vertical curves shall conform to the values found in Tables IIc and IId.

TABLE IIc – DESIGN CONTROLS FOR CREST VERTICAL CURVES BASED ON STOPPING SIGHT DISTANCE
Design Speed	Minimum k
25	20 – 20
30	30 – 30
35	40 – 50
40	60 – 80
45	80 – 120
50	110 – 160
55	150 – 220


k = L = feet A percent	A = Algebraic difference in grades, percent
	L = Length of vertical curve, feet.

TABLE IId – DESIGN CONTROLS FOR SAG VERTICAL CURVES BASED ON STOPPING SIGHT DISTANCE
Design Speed	Minimum k
25	30 – 30
30	40 – 40
35	50 – 50
40	60 – 70
45	70 – 90
50	90 – 110
55	100 – 130


k = L = feet A percent	A = Algebraic difference in grades, percent
	L = Length of vertical curve, feet.

(Ord. 2875 Appx. § 210.5, 2003)

18.12.060 Intersection sight distance policy.

It is the policy of the city of St. Helens to have the engineer evaluate safe intersection sight distance using the principles and methods recommended by AASHTO. The following minimum standards shall apply:

(1) Intersection (and Driveway) Sight Distance. The following table is for intersection and driveway sight distances:

TABLE IIe – CORNER SIGHT DISTANCE
Design Speed (MPH)	Minimum Corner Sight Distance (Feet)
20	210
30	310
40	415
50	515
60	650

For purposes of this calculation, the driver’s eye is assumed to be 15 feet from the near edge of the nearest lane of the intersecting street, and at a height of three and one-half feet above the approach street pavement. The top of the vehicle on the intersecting street is assumed to be four and one-fourth feet above the cross-street pavement. There shall be nothing to block observation of objects between six inches and four and one-fourth feet above grade in both directions. The only exceptions should be for luminaire or utility poles, conforming traffic control devices, and fire hydrants. Cumulative effects must be considered by the engineer, and all efforts taken to minimize sight obstructions.

In some locations, maintenance of the required sight distance may require restrictions to potential development outside the public right-of-way. If so, the project engineer shall demonstrate that adequate restrictions are in place (and enforceable by the city) to ensure that the required sight distance can be maintained in the future.

Modifications or exceptions to these standards shall be approved by the city engineer. (Ord. 2875 Appx. § 210.6, 2003)

18.12.070 Angles between intersecting streets.

The following specifies the minimum requirements for intersections:

(1) The interior angle at intersecting streets shall be kept as near to 90 degrees as possible and in no case shall it be less than 60 degrees. A tangent section shall be carried a minimum of 25 feet each side of intersecting right-of-way lines.

(2) Intersections which are not at right angles shall have a minimum corner radius of 20 feet along the right-of-way lines of the acute angle. The right-of-way radii at intersections shall be sufficient to maintain at least the same right-of-way to curb spacing as the lower classified street.

(3) Minimum radius at the curb line for any intersection shall be 20 feet. Larger curb line radii may be required when intersecting a higher classified street.

(4) Sidewalk access ramps shall be provided at all corners of all intersections, regardless of curb type, and shall conform to the standard drawings. (Ord. 2875 Appx. § 210.7, 2003)

18.12.080 Cul-de-sacs, eyebrows, turnarounds.

The following specifies the minimum requirements for cul-de-sacs, eyebrows, and turnaround areas. Other turnaround geometrics may be used when conditions warrant and city engineer approves the design and application of its use.

(1) Cul-de-sacs, eyebrows, and turnaround areas shall be allowed only on local streets and commercial/industrial streets.

(2) Cul-de-sacs shall not be more than 400 feet in length, except as approved by the fire marshal. The length of a cul-de-sac shall be measured along the centerline of the roadway from the near side right-of-way of the nearest through traffic intersecting street to the farthest point of the cul-de-sac right-of-way.

(3) Minimum radius for cul-de-sac and turnaround right-of-way in residential zones is 42 feet. Minimum roadway radius is 35 feet.

(4) Minimum radius for cul-de-sac and turnaround right-of-way in commercial and industrial zones is 50 feet. Minimum roadway radius is 42 feet.

(5) The minimum curb radius for transitions into cul-de-sac bulbs shall be 20 feet, and the right-of-way radius shall be sufficient to maintain the same right-of-way to curb spacing as in the adjacent portion of the road.

(6) An eyebrow corner may be used on a local street where expected ADT will not exceed 500 vehicles per day or as otherwise approved by the city engineer. Minimum curb radius on the outside of an eyebrow corner is 36 feet; minimum right-of-way radius is 45 feet. Eyebrow geometry shall be evaluated on the basis of turning requirements for fire department vehicles. (Ord. 2875 Appx. § 210.8, 2003)

18.12.090 Driveway approaches.

The city engineer has the authority to limit access and access locations. Access to streets and highways under Columbia County or state of Oregon jurisdiction must be formally approved by those entities at the applicant’s initiative and expense.

The following specifies the minimum requirements for driveways:

(1) Driveways shall not be permitted on streets with existing or proposed nonaccess reserve strips.

(2) Driveways shall be located a minimum of 25 feet from any intersection, measured from the flow line of the intersecting street when fully improved to the nearest side of the driveway.

(3) Driveway width shall be a minimum of 12 feet and a maximum of 18 feet. Wider driveways may be allowed under special circumstances if approved by the city engineer.

(4) The spacing requirements shall conform to the requirements of the city of St. Helens Development Code.

(5) Concentrated surface runoff shall not be allowed to flow over any driveway or sidewalk into the street.

(6) Driveways shall meet the minimum intersection sight distance requirements.

(7) Water meter boxes shall not be located in a driveway or the driveway wing. (Ord. 2875 Appx. § 210.9, 2003)

18.12.100 Curbs and grading.

When new curbing is being placed, a stamp or tag shall be placed to mark where each water and sanitary sewer service crosses the curb line. An imprinting stamp shall be used and the impression left for a water service shall be the letter “W”; for a sanitary service, it shall be the letter “S.” These impressions shall be two inches high, placed on the top of the curb.

(1) The following specifies the requirements for curbs and cross-slope grading for streets:

(a) All streets shall include monolithic curb and gutters on both sides.

(b) Mountable curb and gutter shall be used only in cul-de-sacs with a radius less than 45 feet.

(2) Grading outside the improved areas shall be as follows:

(a) Minor collectors or higher functional classifications shall have a maximum two percent upward grading to the right-of-way line, and no steeper than one and one-half to one up, or two to one down, outside the right-of-way.

(b) Local street and commercial/industrial functional classifications shall have a maximum two percent upward grading to the right-of-way line, a four to one upward or downward grading within the public utility easement, and no steeper than one and one-half to one up, or two to one down outside the public utility easement.

(c) Retaining walls shall be used if slopes are greater than the one and one-half to one requirement in subsections (2)(a) and (b) of this section or where slope stability is a problem. If slopes are to be maintained (mowed) by the city, a maximum of four to one slope will be required. Retaining walls shall be constructed to a height where the slope is no more than one and one-half to one. (Ord. 2875 Appx. § 210.10, 2003)

18.12.110 Sidewalks and clustered mailboxes.

(1) The location of neighborhood mailboxes, or clustered mailboxes, must be determined before installation of the sidewalk. Where clustered mailboxes or other objects larger than single mailboxes are within a sidewalk, the walk shall be widened to provide clearance equal to the required sidewalk width in accordance with the standard details.

(2) In no case shall the sidewalk clear space be smaller than 36 inches.

(3) Ramps, landings, changes in level, and protruding objects along the accessible route to the clustered mailbox shall comply with the applicable ANSI standards.

(4) Edge protection along an accessible route to the clustered mailbox shall be in accordance with the applicable ANSI standards.

(5) At least one turning space shall be provided at the front of each clustered mailbox unit. The turning space shall conform to the applicable ANSI standards and shall either be:

(a) A circular space having a 72-inch (1,829 mm) minimum diameter; or

(b) A T-shaped space within a 72-inch (1,829 mm) minimum square, with arms and base 48 inches minimum (1,219 mm) in width. Each arm of the T shall be clear of obstructions 24 inches (610 mm) minimum in each direction, and the base shall be clear of obstructions 36 inches (914 mm) minimum.

(6) The sidewalk clear space and turning space may overlap. (Ord. 3164 § 3 (Att. B), 2012; Ord. 2875 Appx. § 210.11, 2003)

18.12.120 Guardrails.

(1) The decision of whether to install a guardrail or not shall be based on information found in AASHTO publication, “Guide for Selecting, Locating, and Designing Traffic Barriers.”

(2) Guardrails shall be designed and constructed per ODOT’s “Standard Drawings for Design and Construction.” (Ord. 2875 Appx. § 210.12, 2003)

18.12.130 Transitions.

(1) Street width transitions from a narrower width to a wider width shall be designed with a 10 to one taper.

(2) For street width transitions from a wider width to a narrower width, the length of transition taper shall be designed with a 30 to one taper.

(3) Delineators, as approved by the city engineer, may be installed to define the configuration. Maximum spacing of delineators shall be the numerical value of the design speed, in feet (i.e., 35-foot spacing for 35 mph).

(4) In situations where a tapered transition cannot be provided, a barricade shall be installed at the end of the wider section of the street and a taper shall be appointed and delineated as approved by the city engineer. The barricade shall conform to the standard drawings. If the wider section does not provide an additional travel lane, only a barricade is required without the transition. (Ord. 2875 Appx. § 210.13, 2003)

18.12.140 Superelevation cross-sections.

(1) Offset crown cross-sections are not acceptable as superelevation sections.

(2) Superelevation sections shall be designed using AASHTO guidelines.

(3) Superelevation transitions shall be designed to not allow concentrations of storm water to flow over the travel lanes. (Ord. 2875 Appx. § 210.14, 2003)

18.12.150 Stub streets.

Stub streets that are to allow for future extensions shall be barricaded and signed as per the standard drawings. (Ord. 2875 Appx. § 210.15, 2003)

18.12.160 Private streets, parking lots, and common driveways.

Streets, parking lots, and driveways on private property shall meet the requirements of the Development Code. The engineer shall provide a pavement section design which provides a minimum loading capacity of 12,500 pounds per tire (considered to be one-half square feet). This design must meet or exceed the following minimum standards:

Areas used for required parking or maneuvering of vehicles shall have a durable, hard surface. In all residential areas, a minimum of two and one-half inches asphalt over four inches of aggregate base will be provided or four inches of Portland cement concrete over two inches of aggregate base. In commercial and industrial areas, either three inches of asphalt over four inches of aggregate base or five inches of Portland cement concrete over two inches of aggregate base is required. The parking surface shall be placed on a well-compacted subgrade. All required parking spaces shall be striped.

The elevation for short-term parking will be no lower than one foot below the 10-year floodplain. The elevation for long-term parking will be no lower than the 100-year floodplain. Long-term parking is defined as an unoccupied vehicle being left in one location for a period of greater than 12 hours.

Private streets serving residential areas shall be designed with travel lanes at or above the 25-year flood elevation but not lower than six inches below the 100-year flood elevation.

Access drives in excess of 150 feet in length shall be provided with approved provisions for the turning around of fire apparatus. (Ord. 2875 Appx. § 210.16, 2003)

18.12.170 Utilities.

Utilities shall be located outside of the paved area of the street if at all possible to avoid future street cuts. On all phased street improvements, the necessary utilities shall be stubbed across the interim improvement to ensure that cuts are not necessary when the road is expanded to its full width.

Except for sanitary sewer, storm sewer, and water, underground utilities intended to provide direct service to adjacent properties with future connections shall not be located in the full-width paved section of a street to be constructed. If all service connections are existing and extend beyond the full-width section of a partially improved street, underground utilities can be located in the future paved section of the street, if approved by the city engineer.

Underground utilities being constructed along existing paved streets shall not be located under the existing pavement unless approved by the city engineer.

Utilities other than public water, public sanitary sewer, and public storm drain, shall be buried in a designated public utility easement.

Underground utilities within the public right-of-way shall be buried a minimum depth of 30 inches as measured from finished grade to top of utility.

When new curbing is being placed, a stamp shall be placed to mark where each water and sanitary sewer service crosses the curb line. The impression left for a water service shall be the letter “W”; for a sanitary sewer service, it shall be the letter “S.” These impressions shall be two inches high, placed on the top of the curb.

Street cuts must have the final pavement repair (matching existing material type) completed within 30 days from the date the pavement is cut unless an extension is approved by the city engineer. The use of “cold patch” and steel plates will be allowed for up to the first 30 days after the pavement is cut, provided a daily inspection by the applicant is made and any necessary repairs are made on a timely basis. If the temporary patch is not monitored and maintained, the city engineer may shorten the 30-day time limit. (Ord. 2875 Appx. § 210.17, 2003)

18.12.190 Temporary parklets – In on-street parking spaces.

The following are procedures for establishing a temporary parklet in an on-street parking space in the city. Applications are received and processed by city administration. The city administrator, or his or her designee, issues a temporary parklet application permit upon review and approval by the city public works, engineering, planning and building departments. The city administrator, or his or her designee, may revoke an approved temporary parklet permit if it is being conducted contrary to this section or any condition of the temporary parklet permit approval, or if the temporary parklet and associated use or activities are otherwise found to be contrary to public health, safety and welfare. The temporary parklet application steps and regulations are as follows:

(1) The maximum duration for a temporary parklet permit is six months; permits can be renewed subject to city approval. The maximum renewal duration is six months per renewal. If a temporary parklet permit becomes void due to revocation, expiration or otherwise, the related improvement shall be immediately removed and the location restored to its original condition.

(2) The applicant selects a location according to location criteria.

(a) Temporary parklets shall only be allowed along nonresidential uses. Temporary parklets along and/or associated with residential uses are prohibited.

(b) Temporary parklets are not permitted on streets where parking lanes become tow-away zones during morning or afternoon hours, in front of fire hydrants, in active bus zones, across driveways, or over manholes or public utility valves or covers.

(c) The proposed site should be located at least one standard-size parking space in from a corner. Otherwise, a protected bollard, curb extension, or other similar feature as approved by the city must be present if located at the corner.

(d) The proposed site should be located on a street with a speed limit of 25 MPH or less. Locations on streets with higher speeds will be considered on a case-by-case basis.

(e) The location of the proposed site shall be generally consistent with potential locations and guidance provided in the St. Helens US 30 and Columbia Boulevard/St. Helens Street corridor master plan.

(f) The street grade shall be less than five percent.

(3) The applicant develops a preliminary conceptual design, using the general design guidelines, design criteria, and design elements below.

(a) General Design Guidelines.

(i) Design for Easy Removal. Because the temporary parklet sits on top of critical infrastructure and utilities, it needs to be designed for easy removal in case of emergency or other needed access to the infrastructure. Some applicants elect to remove the temporary parklet during colder months.

(ii) No Advertising. Logos, advertising, or other branding is prohibited.

(iii) Be Creative. There are possibilities beyond the standard tables and chairs on a platform.

(b) Design Criteria.

(i) Design Quality. What is the level of quality and creativity of the design?

(ii) Public Seating. Does the proposal provide open public use of the space and is not just an extension of a business?

(iii) Streetscape Enhancement. How will the proposal enhance the aesthetic quality of the streetscape?

(iv) Quality of Materials. What is the quality and durability of proposed materials and furniture?

(v) Appropriateness of Location. Is the proposed temporary parklet likely to be well-used and active?

(vi) Community Support. Is there demonstrated neighborhood support for proposal at the proposed location (including neighboring businesses and properties)?

(i) Platform should be on the same plane as and flush with the sidewalk height. At least 12 feet of the platform must be flush with the adjacent sidewalk for wheelchair access.

(ii) Platform must be designed to accommodate the crown and cross slope of the street surface. Close attention must be paid to existing curb condition and height to ensure platform is flush with curb.

(iii) The use of high quality, durable materials capable of withstanding the elements of any season and extended use (with proper permit renewals) is required.

(iv) The design should not include any bolts/anchors or other elements that require disturbing the street surface or sidewalk. No temporary parklet component may weigh more than 200 pounds per square foot.

(v) The platform may not extend beyond six feet from the curb line where there is parallel parking to allow some separation from vehicle travel lanes. Angled or perpendicular parking locations and associated dimensions may be approved on a case-by-case basis, but still must allow some separation from vehicle travel lanes.

(vi) The maximum length of the platform must not be longer than the frontage of the applicant’s/permit holder’s establishment. A platform may be located along the frontage of multiple properties/businesses provided all applicable parties are applicants/permit holders.

(vii) Design must maintain a minimum six-foot clear pedestrian through zone in the sidewalk corridor.

(viii) Platform must be designed to allow for curbline stormwater drainage.

(ix) Platform design must include a physical barrier along the street while maintaining clear visual sightlines to the street. Vertical elements, such as planters and umbrellas, should be included so that the facility is visible to vehicles.

(x) A setback on either end of the platform, adjacent to parallel parking, will need to be reserved for wheel stops with embedded reflective candlesticks or other similar features that reflect light and protect the platform from parking maneuvers. These may be installed by the public works department as deemed necessary after facility construction is complete. Additional features may be added to the final design by city staff for safety.

(xi) Temporary parklet furniture shall be subject to city approval. Furniture must be able to accommodate those with disabilities, wheelchairs, or mobility devices.

(xii) Proposed covers or shelters may be subject to additional structural engineering requirements.

(xiii) Loose surface materials, such as sand or loose stone, are not permitted in the temporary parklet.

(xiv) Public temporary parklets must be clearly posted with signs to differentiate them from private business temporary parklets and restaurant/cafe seating. Such signage shall not conflict with the city sign regulations.

(4) The applicant begins gathering and documenting community support (meetings, letters, petitions, site posting, etc.) to be submitted as part of the application package.

(5) The applicant prepares a detailed design document and plan package. It is recommended to contract or consult with professional design assistance.

(a) Parklet location and context plan;

(b) Detailed site plan;

(d) Sections (profile drawings);

(e) Renderings and perspectives (optional).

(6) An application package consists of the following:

(a) A completed right-of-way encroachment permit application form;

(b) Design document and plan package;

(c) Community support documentation. The applicant shall provide written support of the proposed temporary parklet from adjacent businesses and/or property owners.

(7) The applicant completes the application package and submits for review by the city.

(8) Business and property owners within the immediate vicinity of the proposed temporary parklet will be notified and will have the opportunity to submit comments within 14 days to be included in the evaluation of an application.

(9) If the application is approved, the applicant will finalize and submit construction drawings.

(10) The city will schedule a preconstruction site visit.

(11) The applicant submits payment and provides proof of liability insurance, and the public works department issues a right-of-way encroachment permit, which includes conditions for maintenance.

(a) Fees. The applicable fees, as set by resolution of the city council, may include but not be limited to addressing the following components:

(i) Application/encroachment permit fee.

(ii) Cafe seating permit fee, if applicable.

(iii) Additional costs (e.g., changing/removing loading zone sign), if applicable.

(b) Insurance. Evidence of at least $1,000,000 in liability insurance naming the city as additional insured must be provided. Most businesses already carry this insurance.

(c) Encroachment Permit and Maintenance Terms. The permit requires that the facility is swept daily and debris is removed from under and around the platform a minimum of once a week.

(12) The applicant must install the temporary parklet within 90 days of permit issuance. Failure to do so voids any temporary parklet permit approval.

(13) The applicant must notify the city within 48 hours of completing construction to schedule a post-construction site inspection.

(14) Post-construction, the city will monitor the temporary parklet for compliance with the permit, design guidelines, and maintenance agreement as applicable. (Ord. 3181 § 4 (Att. C), 2015)