Chapter 12.24
STREET DESIGN
Sections:
12.24.050 Private access and driveways.
12.24.060 Street intersections.
12.24.100 Aggregate base course.
12.24.010 Design of streets.
The design of streets shall conform to standards established by this chapter. See Table 4, Table 5, and Table 6 for specifics. (Ord. 22-447 § 1; Res. 22-1611; Ord. 15-392 § 1. Formerly 16.24.080(A))
12.24.020 Private street.
Private streets shall conform to above stated design standards unless otherwise approved by the Town Council. Private streets shall be placed within their own parcel or tract of land. Where site conditions necessitate unique design solutions, modifications may be approved by the Town Council. (Ord. 22-447 § 1; Res. 22-1611; Ord. 15-392 § 1. Formerly 16.24.080(B))
12.24.030 Cul-de-sac streets.
Cul-de-sac streets shall be constructed with a minimum unobstructed turnaround area of fifty (50) feet which shall be free from parked vehicles. The Town Engineer may recommend an equally convenient form of turning and backing areas where extreme conditions justify. The maximum length of cul-de-sac streets shall be six hundred (600) feet or twenty (20) homes, as measured from the intersection of right-of-way lines to the extreme depth of the turning circle along the street centerline. An exception may be made where topography justifies but shall not be made merely because the tract has restrictive boundary dimensions, wherein provision should be made for extension of street pattern to the adjoining unplatted parcel and a temporary turnaround installed. (Ord. 22-447 § 1; Res. 22-1611; Ord. 15-392 § 1. Formerly 16.24.080(C))
12.24.040 Dead-end streets.
Dead-end streets will not be approved except in locations recommended by the Director as necessary to future development of adjacent lands, with an unobstructed temporary fifty (50) foot turnaround. (Ord. 22-447 § 1; Res. 22-1611; Ord. 15-392 § 1. Formerly 16.24.080(D))
12.24.050 Private access and driveways.
Access from private property to any dedicated street shall be constructed in accordance with permits issued by the Town. Width of driveway at the property line shall be a minimum of twelve (12) feet and a maximum of forty (40) feet. The width will depend on the access to be served, i.e., residential or commercial. All residential access treatment within the right-of-way will be constructed with five (5) inches of concrete or two (2) inches of asphalt over five (5) inches of aggregate base. (Ord. 22-447 § 1; Res. 22-1611; Ord. 15-392 § 1. Formerly 16.24.080(E))
12.24.060 Street intersections.
A. Streets intersecting a major street shall do so at a ninety (90) degree angle; intersection of local streets shall not vary from ninety (90) degrees by more than fifteen (15) degrees. Exceptions to these requirements will be considered by the Town Engineer based on terrain and other conditions.
B. Street jogs with centerline offsets less than one hundred twenty-five (125) feet shall be prohibited exceptwhen approved by the Town Engineer. Under special circumstances where local streets intersect collector or arterial streets, the Town Engineer may require minimum centerline offsets of four hundred (400) feet.
C. Local streets intersecting a collector street or arterial street shall have a tangent section of centerline at least one hundred fifty (150) feet in length measured from the right-of-way line of the major street, except that no such tangent is required when local street curve has a centerline radius greater than four hundred (400) feet with the center located on the major street right-of-way line. Where topographic conditions make necessary other treatment to secure the best overall design, these standards may be varied by the Town Council upon the recommendation of the Town Engineer.
D. Street intersections with more than four legs and Y-type intersections where legs meet at acute angles shall be prohibited.
E. At local intersections, property line corners shall be rounded by circular arc, having a minimum radius of twenty-five (25) feet. A twenty-five (25) foot by twenty-five (25) foot triangle shall be provided at each corner of the intersection of two (2) major streets. Under special conditions the Town Engineer may recommend other dimensions for the above. (Ord. 22-447 § 1; Res. 22-1611; Ord. 15-392 § 1. Formerly 16.24.080(F))
12.24.070 Street grades.
The minimum street grade shall not be less than two-tenths (2/10) of one (1%) percent. The maximum street grade shall not exceed a six (6%) percent grade. Street grades between six (6%) percent and ten (10%) percent may be approved only for such distances as topographical conditions make lesser grades impractical. A grade exceeding ten (10%) percent may be approved only when conclusive evidence shows a lesser grade is impractical. (Ord. 22-447 § 1; Res. 22-1611; Ord. 15-392 § 1. Formerly 16.24.080(G))
12.24.080 Surface treatment.
The traveled way of all streets shall be surfaced with asphalt concrete. The placing of asphalt concrete shall be accomplished under generally accepted construction techniques provided in Section 321 of the MAG Standard. (Ord. 22-447 § 1; Res. 22-1611; Ord. 15-392 § 1. Formerly 16.24.080(H))
12.24.090 Structural section.
The thickness of base and surface treatment for all streets shall be based on soil analysis and pavement thickness design provided by the developer. In no case will base be less than eight (8) inches and the surface treatment be less than three (3) inches (compacted thickness). (Ord. 22-447 § 1; Res. 22-1611; Ord. 15-392 § 1. Formerly 16.24.080(I))
12.24.100 Aggregate base course.
All developments will be required to submit a soils report and pavement recommendation prepared by an Arizona-registered geotechnical engineer. The pavement report will recommend at least two alternative structural sections for each street classification. Additional asphalt may be substituted for untreated base at the ratio of one to three (1:3). The top four (4) inches must be ABC, the balance may be ABC or select material.
|
Street Classifications |
Untreated Base (Minimum) |
Asphalt Base Course |
Asphalt Surface Course |
|---|---|---|---|
|
Arterial Roadway (Hwy 260) |
10" |
3" – A 1 1/2 |
2" – C 3/4 |
|
Collector Roadway |
7" |
3" – A 1 1/2 |
2" – C 3/4 |
|
Local Street Rural Residential |
8" |
2" – C 3/4 |
2" – D 1/2 |
|
Local Street Suburban/Urban |
8" |
2" – C 3/4 |
2" – D 1/2 |
|
Local Street Commercial |
10" |
2" – C 3/4 |
2" – D 1/2 |
|
Street Type/Category |
Arterial |
Collector |
Local Rural |
Local Suburban/Urban |
Local Commercial |
|---|---|---|---|---|---|
|
Design Speed |
55 |
35 |
30 |
30 |
30 |
|
Min. Radius of Horizontal Curves w/o Superelevations (ft) |
1,800 |
500 |
200 |
200 |
200 |
|
Min. Length of Tangent between Reverse Curves (ft) |
300 |
100 |
100 |
100 |
100 |
|
Min. Length of Tangent between Curves – Same Direction (ft) |
550 |
100 |
100 |
100 |
100 |
|
Min. Vertical Curve (ft) |
500 |
100 |
100 |
100 |
100 |
|
Passing Sight Distance (ft) (per ASHTO) |
1,950 |
|
|
|
|
|
Right Angle Intersection Sight Distance (ft) (per ASHTO) |
860 |
|
|
|
|
|
Min. Tangent Length Approaching Intersections (ft) |
300 |
200 |
150 |
150 |
150 |
|
Roadway Classification |
Zoning District |
R/W Width |
Pavement Width1 |
Curb Type |
# Drive Lanes2 |
Sidewalk or Pathway and Location |
On-Street Parking |
Landscape Strip |
Esmt Required |
|---|---|---|---|---|---|---|---|---|---|
|
Arterial Street (Hwy 260) |
---- |
15-250 |
64 |
Vertical |
2 + Turn |
S/W @ b.o.c. each side |
No |
20 |
None |
|
Collector Street |
---- |
60-80 |
40 |
Vertical |
1 + Turn |
S/W @ 10' b.o.c. each side |
No |
10 |
8' PUE and S/W esmt. |
|
Local Street Rural Res. |
R1/Low |
50 |
24 |
Ribbon |
1 |
Path @7' b.o.c. |
No |
13 |
None |
|
Local Street Suburban Res. |
R1-2 |
50 |
28 |
Ribbon |
1 |
Path @ 5' b.o.c. 1-side |
1-side |
11 |
None |
|
Local Street Suburban Res. |
R1-4, MH-4 |
50 |
24 |
Roll |
1 |
S/W @b.o.c.7 |
No |
13 and 8 |
8' PUE both sides |
|
Local Street Suburban Res. |
R1-4, MH-4 |
50 |
28 |
Roll |
1 |
S/W @b.o.c.7 |
1-side |
11 and 6 |
8' PUE both sides |
|
Local Street Suburban Res. |
R1-4, MH-4 |
60 |
36 |
Roll |
1 |
S/W @b.o.c.7 |
2-sides |
12 and 7 |
8' PUE both sides |
|
Local Street Urban Res. |
R1-6, MH-6 |
60 |
36 |
Vertical |
1 |
S/W @b.o.c.7 |
2-sides |
7 and 7 |
8' PUE both sides |
|
Local Street Commercial |
---- |
60 |
40 |
Vertical |
1 + turn |
S/W @b.o.c.7 |
2-sides |
5 and 5 |
8' PUE both sides |
1. Pavement width shall be measured from back of curb to back of curb (b.o.c).
2. Number of drive lanes is for each direction. All drive lanes shall be twelve (12) feet in width.
3. Sewer utilities shall be located under the pavement or within a sewer easement.
4. Dry utilities shall be located within the PUE.
5. Sidewalks (S/W) shall be five (5) feet in width, constructed of portland cement concrete.
6. Pathways shall be six (6) feet in width.
7. The Town strongly encourages minimum ten (10) feet curb separated sidewalks (see Section 16.24.040(B)(2)(f)) for unbuilt common area incentive.
8. As lot widths are reduced to less than fifty (50) feet and the overall project density increases to more than three point five (3.5) dwelling units per acre and the total number of lots or dwelling units exceeds forty (40), then the rights-of-way shall be increased to thirty-six (36) feet.
(Ord. 22-447 § 1; Res. 22-1611; Ord. 15-392 § 1. Formerly 16.24.080(J))