§ 42-187. Streets and alleys.

(a)

General requirements. The arrangement, character extent, width, grade and location of all proposed streets shall be related to existing and planned streets, to topographical conditions, to public convenience and safety, and in their appropriate relation to the proposed uses of the land to be served by such streets. Adequate streets shall be provided by the subdivider and the arrangement, character, extent, width, grade and location of each shall conform to the comprehensive plan of the city and shall be considered in their relation to existing and planned streets, to topographical conditions, to public safety and convenience, and in their appropriate relationship to the proposed uses of land to be served by such streets. The street layout shall be devised for the most advantageous development of the entire neighborhood.

(b)

Streets on comprehensive plan. Where a subdivision embraces a street as shown on the city comprehensive plan, such street shall be platted in the location and of the width indicated by the comprehensive plan.

(c)

Relation to adjoining street system. The proposed street system shall extend all existing major streets and such collector streets up to logical termination according to the preceding criteria. Local access streets are to be extended as may be desirable for public safety and convenience of circulation. Where possible, the width and the horizontal and vertical alignment of extended streets shall be preserved. All streets should be designed to be in line with existing streets in adjoining subdivisions.

(d)

Projection of streets. Where adjoining areas are not subdivided, the arrangement of streets in the subdivision shall make provision for the proper projection of streets into such unsubdivided areas.

(e)

Restriction of access. The reservation in private ownership of strips of land at the end of proposed or existing streets and intended solely or primarily for the purpose of controlling access to property not included in the subdivision shall be prohibited.

(f)

Half streets. Half streets shall be prohibited, except where essential to the reasonable development of the subdivision in conformity with the other requirements of these regulations, and where the commission finds it will be practicable to require the dedication of the other half when the adjoining land is subdivided. The other half of the street shall be platted within the adjacent tract at the time it is platted.

(g)

Perimeter streets. When land proposed to be subdivided is partially or totally bounded on one or more sides by a street way or thoroughfare having a width of less than that specified in this section, such land shall be laid out so as to provide street widths specified herein. A half street along adjoining property which has not been subdivided may be shown on the general development plan of an entire subdivision, but no lots fronting upon such half street shall be included in the subdivisions that are approved.

(h)

Design of local streets. Local streets shall be laid out so as to serve only local traffic and to discourage their use by through traffic. Local streets in residential subdivisions shall be designed in a curvilinear manner, except when:

(1)

In the determination of the planning and zoning commission, the shape or topography of the subdivision, existing zoning or the patter of the adjacent street would make the provision of such curvilinear streets impractical; or

(2)

The subdivision is part of and conforms to an unexpired preliminary plat approved prior to the adoption of the ordinance establishing these rules, regulations and procedures.

(i)

Adequate access. To ensure adequate access to each subdivision, there should be at least two, planned points of ingress and egress, except for approved culs-de-sac.

(j)

Residential access to collectors and thoroughfares. Subdivisions serving areas zoned single-family residential land which abut on or contain an existing or proposed thoroughfare or collector street should be designed so that direct vehicular access from any lot to such street is prohibited. The design should provide a minimum number of access points to collector streets.

(k)

Relation to lots. All streets should be planned so that all resulting lots shall be sufficient size and shape to conform to applicable zoning regulations. Streets should be platted to allow two tiers of lots between streets when possible.

(l)

Street names. Names of new streets shall not duplicate or cause confusion with the names of existing streets, unless the new streets are a continuation of, or in alignment with existing streets, in which case names of existing streets shall be used. Streets shall be named to provide continuity with existing streets.

(m)

Street class requirements.

(1)

Streets are categorized into the following six classes:

Street Classification	Functions — Uses
Large lot rural	Distributes traffic to and from residences. Short in length, non-continuous to discourage through traffic. Low-density residential/single-family.
Local residential	Distributes traffic to and from residences. Short in length, non-continuous to discourage through traffic. Low-density residential/single-family.
Residential collector	Carries traffic from local streets to arterials. Also may serve local facilities such as schools, churches. Uses served would include medium and high density residential, limited commercial facilities, elementary schools, some small offices and as direct access within industrial parks.
Commercial collector	Carries heavy traffic to major commercial and industrial facilities from arterials. Uses would include office park, industrial parks, and community level commercial facilities.
Arterial (minor or principal)	Major traffic carriers. Receives traffic from collectors and distributes to major activity centers. Also feeds through-traffic to freeways. Uses would include high schools, universities, other major educational facilities, concentrations of high-density residential, regional commercial facilities, other concentrated commercial facilities, industrial complexes, and major public facilities such as airports.

 

(2)

Street layout shall provide for continuation of collector streets in areas between arterials.

(3)

Those local streets designated by the commission shall be extended to the tract boundary to provide future connection with adjoining unplatted lands. In general, these extensions should be at such intervals as necessary to facilitate internal vehicular circulation with adjoining unplatted lands.

(4)

Where single-family or duplex uses abut an existing or proposed arterial street, the plat or dedication instrument will provide:

a.

The subdivision of lots so as to back into the primary arterial and front onto a parallel local street with no access from the arterial.

b.

Providing a series of cul-de-sac, U-shaped local streets, or short loops entered from and designed generally at right angles to a parallel street, with the rear lot lines of their terminal lots backing into the arterial street.

c.

Lots to side onto the arterial with a non-access restriction on the arterial side.

d.

Reverse frontage with screening and containing a non-access restriction along the rear property line.

e.

Other treatment as may be necessary or required for adequate protection of adjoining properties, and as approved, by the commission after taking into consideration the proposed method of off-street parking and maneuvering which will prevent the necessity of backing into the arterial street.

(n)

Street design.

(1)

Right-of-way widths. Street right-of-way shall be in conformance with the comprehensive plan of the city. In no event shall a street have a right-of-way width of less than shown in Table 45-1.

(2)

Pavement widths. Pavement widths shall be measured from the face of one curb to the face of the other curb and shall conform to the requirements of the comprehensive plan or city standards. Unless otherwise approved by the city, local streets shall have a minimum pavement width as shown in table 45-1. Wider pavement widths shall be provided when required by the planning and zoning commission to handle increased or unusual traffic conditions.

(3)

Pavement design.

a.

For local streets serving primarily residential areas, the developer shall construct five inches of reinforced concrete over six inches of lime stabilized subgrade. The developer's engineer shall provide soil tests to determine by recommendation of a reputable soil testing laboratory, if lime stabilization of the subgrade is needed in conjunction with five inches of reinforced concrete pavement. The recommendations shall address the percentage of lime to be applied.

b.

For collector streets, and arterial streets and streets serving primarily commercial and industrial areas, the developer shall construct a minimum of seven inches of reinforced concrete over six inches of lime stabilized subgrade or seven inches of reinforced concrete.

c.

The developer's engineer shall provide soil tests to determine by recommendation of a reputable soil testing laboratory, if lime stabilization of the subgrade is needed in conjunction with the reinforced concrete pavement. The recommendations shall address the percentage of lime to be applied. As a part of the soils test for determining lime or cement content, a pavement design shall be provided for thoroughfares. The design shall be in accordance with AASHTO guidelines and shall be based upon a 20-year design life. A pavement design shall be provided for commercial and industrial use roadways. A parabolic crown shall be provided in accordance with the city's standard details. The distance between expansion joints shall not exceed 600 feet. A five-inch crown is required for a local residential street. The concrete for all street sections shall have a minimum compressive strength of 3,600 pounds per square inch (psi). The city engineer may require more stringent design requirements in locations of unusual soil or traffic conditions. Any deviations from the typical sections shall require the approval of the city engineer.

d.

Consideration may be given to permitting a different subgrade and pavement thickness from the foregoing provided that the developer's engineer provides soils tests and design calculations based on the Texas Triaxial Method and all such soils tests and calculations are approved by the city engineer.

e.

All materials furnished for the paving of streets and all construction methods shall fully conform to the appropriate sections of the Standard Specifications for Public Works Construction (NCTCOG).

f.

Curb and gutter shall be constructed as detailed and specified in the standard specifications for construction.

(4)

Street alignment. A curved street pattern which follows the topography is preferred to a grid pattern imposed upon the land. This provides use of the streets for drainage purposes, a more interesting pattern of development, and slows traffic driving through residential neighborhoods. Streets should traverse the topography in the following manner:

a.

Cross streams and drainageways at a right angle; this minimizes bridge and culvert costs.

b.

Streets on sloping terrain should gradually cross hills rather than directly up and down.

c.

Culs-de-sac and loop streets should curve with the flow of the topography to best handle drainage.

d.

Where possible, drainage should be away from the cul-de-sac or loop street.

e.

Property boundaries should not serve as the primary basis for street layout, with other property features (topography, soils, vegetation, etc.) serving as the overall guide.

Table 45-1
City of Justin Thoroughfare Standards

Street Designation	Street Classification	Minimum Right-of-Way Width	Minimum Pavement Width	Lanes	Parkway/ Sidewalk
LL	Large lot rural	60 feet	26' plus 2' shoulder (or 8 header/ribbon curb)	Two 13' driving lanes, one each direction No on-street parking	15' — 18' with drainage ditch and no sidewalk
LR	Local residential	50'	28'	Two 10' driving lanes and one 8' parking lane or one 12' driving lane and two 8' parking lanes	11' with 4' sidewalk
RC	Residential collector	60'	36'	Two 10' driving lanes and two 8' parking lanes	12' with 4' sidewalk
CC	Commercial collector	60'	40'	Two 12' driving lanes and two 8' parking lanes	10' with 5' sidewalk
M4U	Minor arterial, 4 lanes undivided	68'	48'	Four 12' driving lanes no on street parking	10' with 6' sidewalk
P6D	Primary arterial 6 lanes divided	120'	2 @ 36'	Three 12' driving lanes (each side) no on street parking 24' median (typical) or 12' median and 12' left turn lanes as needed	12' with 6' sidewalk

 

(5)

Horizontal curves.

a.

Where streets classified as local are platted with curves, the degree of curvature should, as much as is practical, be consistent with the criteria for horizontal curves and minimum stopping sight distance for the design speed, in accordance with good engineering practice.

b.

When streets classified as collector or arterial are platted with curves, the degree of curvature shall be such so that the street when constructed will meet the requirements for horizontal curves and minimum stopping sight distance, etc., for the design speed, in accordance with good engineering practice.

c.

Horizontal curves for local streets shall not be less than 250 feet along the centerline radius, collector streets not less than 400 feet along the centerline radius, and thoroughfares not less than 1,200 feet along the centerline radius. Local streets should be designed in a curvilinear manner to the extent possible, and avoid long street segments with a maximum centerline radius less than 800 feet. These requirements may be made more stringent by the city engineer if deemed necessary to provide minimum stopping distance, sight distance, design speeds, and other safety requirements consistent with good engineering practices.

(6)

Design speeds. Unless otherwise approved by the city council, thoroughfares should be designed to have a safe running speed of 40 miles per hour, collector streets have a safe running speed of 35 miles per hour, and local residential streets should have a safe running speed of 30 miles per hour.

(7)

Minimum and maximum grades. Street and alley grades shall conform to the natural terrain where possible. No street or alley shall have a grade less than 0.40 percent. Local streets shall not exceed a grade of ten percent, collector streets shall not exceed a grade of seven percent, and thoroughfares shall not exceed a grade of five percent.

(8)

Intersections. Street intersections shall be as nearly at right angles as practicable, giving due regard to terrain and topography, and in no case shall vary from 90 degrees by more than five degrees without specific authorization by the city engineer. Intersections of collectors and local should not vary from 90 degrees by more than 15 degrees.

a.

The intersection of two local streets shall have a minimum curb return radius of 15 feet. The intersection of a local street or collector street with a collector street shall have a minimum curb return radius of 25 feet. Intersection of a collector street or thoroughfare with a thoroughfare shall have a minimum curb return radius of 35 feet. If the intersection angle between any two streets varies by more than five degrees from a right angle, the minimum curb return shall be determined and approved by the city engineer.

b.

Y intersections should not be permitted.

(9)

Street jogs or offsets. Wherever possible, street jogs with centerline off-sets of less than 135 feet for local streets shall be avoided. No street jogs or off-sets are permitted for collector or thoroughfare streets. Greater centerline offsets as may be required by the city engineer shall be planned where necessary for traffic safety.

(10)

Thoroughfare intersections. Thoroughfares should be intersected only by collector streets or other thoroughfares, rather than local streets. No off-sets at the intersection of two collector streets and/or thoroughfares shall be permitted. There shall be a minimum of 600 feet between intersections of thoroughfares and/or collector streets.

(11)

Sight distance. Sight distance is also important at each intersection. Recommended sight distances are as follows:

a.

Arterial streets with median: 500 feet.

b.

Arterial streets without median: 800 feet.

c.

Collector streets: 300 feet.

d.

Minor streets: 200 feet.

Visibility triangles shall be provided at all street intersections, either as dedicated right-of-way or as public open space easement. The minimum triangle shall be 35 feet along each right-of-way line, though additional open space easement may be required when necessary to achieve the necessary sight distances. A 45-foot triangle is recommended for collector and thoroughfare street intersections. The city shall utilize the sight distance requirements established by the Institute of Transportation Engineers' Guidelines for Urban Major Street Design (1990) in making its determinations.

(12)

Dead end streets. Streets designated to be dead-ended permanently shall be platted and constructed with a paved cul-de-sac. Any dead-end street of a temporary nature, if longer than 200 feet, shall have a surfaced turning area 80 feet in diameter for a cul-de-sac. Temporary dead-end street shall have provisions for future extension of the street and utilities and, if the temporary cul-de-sac is utilized, a reversionary right to the land abutting the turn-around for excess right-of-way shall be provided. When the planning and zoning commission determines that there is a reasonable expectation that a dead-end street will be extended within two years, construction of a temporary cul-de-sac may be approved. The planning and zoning commission may waive temporary cul-de-sac requirements for dead-end streets when the street is less than 200 feet in length. The portion of the temporary cul-de-sac which will serve as an extension of the street shall be constructed in accordance with the city standards and that additional portion of the temporary cul-de-sac shall be in accordance with the city standards for a permanent cul-de-sac.

(13)

Cul-de-sacs. A street ending permanently in a cul-de-sac should not be longer than 600 feet and shall be provided at the closed end with a turn-around having an outside roadway diameter of at least 80 feet, and a street property line diameter of at least 100 feet. On extra wide lots, culs-de-sac may be longer.

(14)

Curbs and gutters. Curbs shall be installed by the subdivider on both sides of all interior streets, and on the subdivision side of all streets forming part of the boundary of the subdivision. The city has adopted the six-inch high curb as the standard for all streets. In limited places where monolithic curb is not provided after approval by the city, the gutter shall be 18 inches wide.

a.

The subgrade for curb and gutter typically shall consist of six inches of lime or cement-stabilized base material. In cases where lime stabilization is not feasible, six inches of mechanically compacted crushed stone or six inches of three-sack concrete (2:27) may be used as base material. The stabilized base must extend six inches beyond the curb and gutter.

b.

The curb and gutter shall be constructed monolithically in accordance with the city's standard details and standard specifications. Concrete shall be 5½-six sack, 3,600 psi design with two No. 3 steel bars placed longitudinally with the curb and gutter. Joints shall be scribed in the curb and gutter at distances no greater than 12 feet and expansion joints placed at each radius or linear distances of 250 feet or less. Any pavement damaged during curb and gutter installation must be restored to meet city specifications.

c.

All improvements shall be subject to inspection and approval of the city inspector. All work shall be subject to tests as prescribed by the city inspector, with the cost of such tests borne by the developer or his contractor. If a test fails to meet specifications, the contractor shall bear the expense of removing the faulty section delineated by the city inspector, reconstructing the section, and performing any subsequent tests required by the city inspector.

d.

Wheelchair ramps shall be provided at all street intersections, unless otherwise approved in writing by the city engineer. Wheelchair ramps shall also be provided at driveway curb returns where the location of the curb return intersects the sidewalk and results in a barrier to handicapped access. Wheelchair ramps shall be provided in commercial and industrial parking lots that are required to provide handicapped parking spaces. All wheelchair ramps shall be constructed in accordance with the city's standard details and in compliance with ADA requirements, unless otherwise approved by the director of community development.

(15)

Street costs and city participation. The owner or developer shall be responsible and pay all costs for the design and construction of streets within the proposed development. The developer shall build these streets in accordance with city standards.

(o)

Alleys.

(1)

General provisions.

a.

Alleys serving single-family residential and duplex areas shall have a minimum right-of-way width of 15 feet. Alley turnouts shall be paved to the property line and shall be 12 feet wide at that point. Alleys shall be paved in accordance with city design standards and specifications, for a minimum width of ten feet exclusive of any curbs which may be required. A uniform transition in alley pavement widths shall be made in a distance of not less than 20 feet.

b.

Alleys serving all other areas or zoning districts shall have a minimum right-of-way and paving width of 20 feet. All other requirements in subsection (1)a of this section, shall apply.

c.

Alleys should intersect streets at right angles or radically to curved streets. Alleys shall be approximately parallel to the frontage of the street and shall be less than on 1,600 feet in length unless specifically approved by the planning and zoning commission.

d.

Dead-end alleys shall be prohibited.

e.

In cases where two alleys intersect or turn a sharp angle, lot corners shall be platted so that a triangular area of 25 feet by 25 feet or greater, is dedicated as part of the alley for the purpose of providing a minimum radius of 30 feet to the inside edge of the alley paving.

f.

Alley paving should have a minimum grade of 0.4 percent and a maximum grade of ten percent.

1.

Residential alleys shall have a minimum pavement thickness of five inches of 5½-six sack concrete with a minimum compressive strength of 3,600 pounds per square inch reinforced with No. 3 bars on 24-inch centers in both directions over six inches of lime or cement stabilized subgrade. The minimum inside radius of any curve shall not be less than 15 feet.

2.

Alleys in commercial and industrial areas shall have a minimum right-of-way and pavement width of 30 feet and a minimum pavement thickness of seven inches of reinforced concrete over six inches of lime or cement stabilized subgrade. A pavement design shall be provided by the developer for commercial and industrial alleys. The minimum inside radius of any curve shall not be less than 20 feet.

(p)

Private streets. Private streets shall be allowed only in limited circumstances and by specific approval of the planning and zoning commission and city council. A perpetual maintenance agreement instrument with the subdivision's homeowner's association is required for plat approval general design standards for streets should be used.

(q)

Traffic control and street signs. The developer shall provide and install all street identification signs and attachment hardware for streets within the subdivision. The street identification signs shall be constructed of extruded aluminum and shall have white reflective letters on a green background. The developer shall provide poles and install any necessary traffic control signs (such as stop signs) as directed by the city engineer.

(r)

Sidewalks and parkways. Unless otherwise approved by the planning and zoning commission, sidewalks shall be installed as follows:

(1)

On the subdivision side of all thoroughfares and collector streets adjacent to a residential subdivision.

(2)

On both sides of all internal thoroughfare, collector, and local streets of a residential subdivision.

(3)

As deemed necessary by the commission in commercial, industrial, and public areas.

(4)

Such additional sidewalks as the subdivider may desire.

(5)

Sidewalks shall be placed in the right-of-way and shall be a minimum of four feet in width. Sidewalks serving commercial areas may be placed at the back of the curb if designed to be five feet in width.

(6)

Swept corner or other approved handicapped access curb ramps shall be provided at all intersections and crosswalks.

a.

Sidewalks shall be provided in locations required by the planning and zoning commission and city council. Sidewalks shall be constructed of concrete in accordance with the city standard specifications and in accordance with the city standard design details. Sidewalks shall have a minimum width of four feet and a minimum pavement thickness of four inches of reinforced concrete. In locations where sidewalks must be located immediately adjacent to the curb and gutter, the minimum width shall be five feet. Sidewalks shall have a minimum cross slope of one-quarter-inch per foot for drainage.

b.

Parkways shall be graded with a slope not less than one-quarter-inch per foot. Except as otherwise provided by city ordinance or policy, no other structures or trees and shrubs shall be allowed to be constructed in the parkway. Landscaping plans for the parkways must conform to the requirements of the city council.

(s)

Medians.

(1)

Medians shall not be constructed in dedicated public right-of-way unless specifically required by and/or approved by the planning and zoning commission and city council. Medians approved for aesthetic purposes shall be maintained by, and at the expense of, the dedicator in accordance with specific contractual arrangements with the city and shall be platted as common area with ownership by a development company or homeowners association. Medians required for traffic control shall be designed for minimum maintenance.

(2)

Median openings. If and when medians are constructed on any arterial street, spacing between median openings should be at least 400 feet. The spacing may be reduced to 300 feet if a competent traffic study shows that a lesser spacing will still safely and efficiently accommodate left-turn movements to existing and projected future development in the immediate vicinity.

(Code 1994, ch. 9, art. 45; Ord. No. 248, exh. A(art. 45), 3-24-1997)