Hillsborough Municipal Code Ch. 16.28 Public Improvement Standards

A. Streets and easements. The subdivider shall improve all streets and easements in the subdivision. Such improvements shall include grading and surfacing of streets, domestic water supply as may be necessary to protect public health and provide fire protection, extension of sanitary sewer service to each lot, storm water drainage, street lighting systems, if required, street name and regulatory signs, underground electric and telephone systems and other public utilities, gutters, paving, curbs, concrete structures, culverts, bridges, drains, water storage tanks, and reservoirs, pumping stations, and removal of vegetation from street rights-of-way as may be necessary, and any other improvements necessary to the use of such public improvements or necessary for the public safety. All subdivision improvements, including the methods, materials, and design of the improvements, shall comply with the provisions of the chapter and conform with the standards and specifications of the town for the construction of public improvements as compiled by the city engineer. Such standards may be changed from time to time at the discretion of the city engineer consistent with sound engineering practice and with the other requirements of this Code, town policy, and other applicable law.

B. Plans and specifications.

1. Before public improvement work is commenced, detailed plans and specifications shall be provided to the city engineer.

2. When the city council has approved the tentative map and the city engineer has approved the plans and specifications, the subdivider may proceed with the work.

3. Inspection and approval of all work shall be done under the supervision of the city engineer.

4. No improvement shall be accepted by the city council for dedication to the town until such time as the completed work has been approved by the city engineer.

C. Costs. The subdivider shall pay to the town the actual costs of the city engineer's services under this chapter, as determined by the city engineer, before the final map is approved by the city council. The city engineer may require that the subdivider pay a deposit in the amount of estimated costs pending completion of the city engineer's services and calculation of the actual costs. If the deposit proves to be in excess of the actual costs, the town shall return the excess to the subdivider upon making such calculation. If the deposit proves to be less than the actual costs, the subdivider shall pay the balance of the actual costs before the final map is approved by the city council.

D. Conditions precedent. The provisions set forth in subsections B. and C. of this section shall constitute conditions precedent to the issuance of a building permit (as set forth in Chapter 15.60) and the commencement of the design review process (as set forth in Chapter 2.12).

(Ord. No. 696, 7-11-2011)

A. Drainage.

1. Sufficient storm drainage work shall be installed to prevent flooding or inundation of streets and adjoining property by storm waters and shall provide sufficient means to dispose of normal water flow and protect pavements against deterioration. Drainage work shall be designed for a twenty-five year storm with no damage from a one hundred year storm to the structure and dwelling unit. Drainage works shall include adequate gutters, catch basins, culvert crossings, storm sewers, underdrains, head walls, bulkheads, trash racks, and other structures, where necessary, and shall incorporate best management practices as required by the water quality control board and green infrastructure measures indicated by the green infrastructure plan approved by resolution of the city council. Runoff factor, subject to variation because of the nature and use of the terrain, shall be clearly stated and shall meet with the approval of the city engineer.

2. Where substantial changes to existing drainage patterns are proposed, the subdivider shall not direct storm drainage onto adjacent properties by surface flows or point discharges or other outlets unless connected directly to an approved public drainage facility. With the approval of the city engineer, drainage to an approved public facility may be accomplished with an easement to connect to adequate existing private drainage facilities or to install new facilities under adjoining property, including access for maintenance.

B. Water supply. Mains, valves, regulators, meter connections, lot services, pumping plants, storage tanks, reservoirs, and other water supply facilities shall be installed as required to provide an adequate water supply to each lot and provide fire protection satisfactory to the fire chief.

C. Street lighting. All new subdivisions shall provide a system of electroliers or street lighting equipment but only if and to the extent required by the city council upon the advice of the city engineer.

D. Undergrounding. Complete underground electric and telephone facilities shall be installed for all lots in the subdivision. "Underground facilities" means all public or private equipment used to provide service to the consumer and includes all cable, wires, conduits, manholes, transformers, junction and terminal boxes, and all similar devices. All underground utilities (including, but not limited to, sewer, water, storm drainage, cable TV, telephone, electricity, gas, lighting, and any other power or communications installations) shall be extended from the street over the property line into the lot before the construction of final pavements, curbs, gutters, or walks. The subdivider is required to underground all overhead utilities along the street frontage adjacent to the property. When the existing overhead utilities along the frontage are on the opposite side of the street fronting the property, the subdivider shall underground all the services to the subdivision to the point of connection to the overhead system.

(Ord. No. 696, 7-11-2011; Ord. No. 757, § 13, 10-14-2019)

A. Easements for utilities. Easements of not less than five feet in width shall be provided on each side of all rear and side lot lines and/or where necessary for public utilities. Easements of greater width may be required where necessary in the opinion of the city engineer.

B. Street widths. The minimum width for city streets shall be forty feet, except that in cases where, in the opinion of the city council, the topography or special conditions make a street of such width impossible, impractical, or unadvisable, such lesser or greater width as is deemed adequate or advisable by the city council may be provided, except that residential streets over two thousand feet in length shall be fifty feet in right-of-way width and the end of cul-de-sac streets shall provide a turning area at least eighty feet in diameter.

C. Intersection angle. Any street intersecting any other street shall do so at an angle that is as nearly ninety degrees as is practical.

D. Street connections. Each street shall connect at both ends to the existing street pattern; provided, however, that where evidence satisfactory to the city council is given that a through street is impossible or impractical, a cul-de-sac may be provided. Any cul-de-sac shall meet the requirements set forth in Section 16.28.040. All streets shall be in alignment with existing adjacent streets by continuation of the centerlines thereof, or by adjustment with curves. Provision shall be made by reservation or extension of streets to boundary lines for future extension of streets through adjoining undeveloped property. Exceptions to the foregoing requirements may be approved by the city council when a normal layout of streets is not possible without resulting detriment to the subdivision or adjoining property.

E. Street grade. No street shall have a slope in excess of sixteen percent. Street slopes shall include a minimum hundred foot vertical curve transition to changes in slope. The roadway centerline through an intersection shall not exceed a five percent slope.

F. Centerline radii. Roadway centerline radii shall be not less than five hundred feet on collector and arterial streets, as identified in the general plan, and not less than two hundred fifty feet on all other streets.

G. Blocks. Blocks shall not exceed two thousand feet in length. At street intersections of approximately ninety degrees, the block corners shall be rounded at the property line on a curve radius of not less than twenty-five feet; provided, however, that the curve radius shall conform to the radius of existing corners at the same intersections where such radius is greater than twenty-five feet. Where streets intersect at angles other than ninety degrees, a radius of such size shall be used as to provide results equivalent to the foregoing, in respect to traffic movement, visibility, and design.

H. Streets at subdivision border. No subdivision shall be approved that includes a less than a standard width street right-of-way within the subdivision at its border unless the subdivider acquires legal authority to improve sufficient land outside of and bordering the subdivision to create a street right-of-way along the border of the subdivision meeting the requirements of subsection B. of this section and unless such right-of-way may legally be dedicated by the subdivider to the town.

I. Street signs. For all streets to be dedicated to the town and private streets, the subdivider shall install traffic signage as set forth in the public improvement agreement or as otherwise directed by the city engineer. Traffic signage includes, but is not necessarily limited to, all pavement markings and striping, street name signs, regulatory, warning, and advisory signs. All signs shall be of a type, size, material, color and manner of installation as to conform with the standards of the town of the standard specifications of the department of transportation.

J. Trees in the right-of-way. Any tree planting or landscaping program in the right-of-way required by the city council as a condition of approval of the tentative map or required by the city engineer as part of the subdivision improvement agreement shall be installed in conformance with such map conditions or improvement agreement.

(Ord. No. 696, 7-11-2011)

A. Definition. For purposes of this chapter, a cul-de-sac is any street closed at one end (i.e., a street whose entrance and exit are one and the same) and that is not continued onto a connecting public street via another connecting public street or via an approved town emergency access drive (which is a dedicated fenced and/or gated access easement with an all-purpose roadway width as approved by the Central County Fire). Examples of the application of this definition are shown in diagrams 1 through 5 of this section.

B. Long cul-de-sacs. No tentative or final map shall be approved providing for a cul-de-sac longer than five hundred feet; provided, however, that the city council may approve a greater length, not exceeding one thousand feet ("long cul-de-sac"), if the city council finds that significant benefits of such greater length have been demonstrated. Vacant lots fronting on culs-de-sac in existence prior to November 11, 1992, shall not be denied development merely because such lots are more than five hundred feet from the street intersecting the cul-de-sac.

C. Measurement. The length of a cul-de-sac shall be the distance (as measured along the center line of the street or streets), from the farthest point of the turnaround bulb to the point where the cul-de-sac intersects the extended street gutter line or the centerline intersection of the approved emergency access drive. Examples of measurement are shown in diagrams 1 through 4 of this section.

D. Council determinations. In approving a long cul-de-sac, the city council shall consider the topographical features of the land along the cul-de-sac, including, but not limited to, the slope of the paved cul-de-sac and the possible slopes of the driveways, the number of fire hydrants and the nature and number of other public fire protection devices (such as water storage tanks or cisterns) located on the connecting street and proposed to be located on the cul-de-sac, and any other relevant factors bearing on public safety. The city council shall determine how many dwellings shall be permitted along the long cul-de-sac, whether the minimum lot size and/or minimum setbacks otherwise applicable shall be increased and by how much, and whether the maximum square footage otherwise allowable under Title 17 shall be decreased and by how much.

E. Stricter standards. For any cul-de-sac, regardless of length, the city engineer may recommend and the city council may require stricter standards, including, but not limited to, a greater street width, a larger cul-de-sac bulb, and/or a shorter street length, than otherwise required.

F. Diagrams. The following diagrams illustrate the provisions of subsections A and C of this section:

[Figure]

DIAGRAM 1—"TYPICAL CUL-DE-SAC"

[Figure]

DIAGRAM 2—"PARTIAL CUL-DE-SAC"

[Figure]

DIAGRAM 3—"PARTIAL CUL-DE-SAC"

[Figure]

DIAGRAM 4—"CUL-DE-SAC LENGTH DEFINED" (Marked 1 and 2)

[Figure]

DIAGRAM 5—"NOT A CUL-DE-SAC"

(Ord. No. 696, 7-11-2011)

All public improvements shall be designed and constructed taking into account the lot requirements set forth in Chapters 16.08 and 16.12.

(Ord. No. 696, 7-11-2011)

In special circumstances where necessary to accomplish a satisfactory street pattern or to accommodate local terrain, the city engineer may recommend and the city council may allow a variation of the centerline radii, street grade, block length, or angle of lot side lines from the requirements set forth in this section.

(Ord. No. 696, 7-11-2011)

No entrance monuments, entrance arches, locked security gates, or any other monuments of any kind or size intended to mark the entrance to subdivisions shall be allowed or installed.

(Ord. No. 696, 7-11-2011)

If, at the time of approval of the final map by the city council, any required public improvements have not been completed and accepted in accordance with standards established by the town, the city council shall require, as a condition precedent to the approval of the final map, that the owners of the subdivision enter into one of the following agreements with the town as selected by the town:

1. An agreement to complete such improvements by a specified deadline at the subdivider's expense and guaranteed by the security specified in the Subdivision Map Act. The subdivider shall provide a performance bond and labor and materials bond in an amount each equaling one hundred percent of the city engineer's estimate for all public improvements plus the town's attorney fees incurred in connection with an action to obtain compliance with the agreement for subdivision improvements and to enforce the town's rights under the performance bond. The performance bond shall be in a form approved by the city attorney.

2. An agreement to initiate and consummate proceedings under an appropriate special assessment act for the financing and completion of all such improvements; provided, however, that if the public improvements are constructed pursuant to a special assessment act, the town shall bear no expense related thereto and provided, further, that if the public improvements are not completed under such special assessment act, they shall be completed pursuant to an agreement as described in paragraph 1. above.

(Ord. No. 696, 7-11-2011)