The street and highway layout of each subdivision shall be based upon the section of the Streets and Highways Master Plan for the portion of the City within which the subdivision lies. Any street which provides the principal means of vehicular access to any lot in a subdivision shall be a dedicated public right-of-way accepted by the City of Mill Valley as a part of its official City street system. The requirement shall apply to subdivisions containing less than five lots, as well as to subdivisions of five lots or more.
(Ord. 447 § 2.1a, April 17, 1956; Ord. 633 § 4, May 17, 1965)
The center lines of all highways shall be the continuations of the center lines of existing highways in adjacent and contiguous territory. In cases in which straight continuations are not physically possible, such center lines may be continued by curves, and shall be in general conformity with the plans made for the most advantageous development of the area in which the subdivision lies.
(Ord. 447 § 2.1b, April 17, 1956)
Widths of local streets shall not be less than those set forth in Table One. Increased widths may be required where streets are to serve commercial property or where probable traffic conditions warrant such. The apportioning of the street width between roadways, sidewalks, and grass strips shall be in accordance with the standard street sections as set forth in Table One, on file in the office of the City Clerk, except in situations where some other apportionment will enhance the conservation of energy.
(Ord. 447 § 2, April 17, 1956; Ord. 999 § 7, November 15, 1982)
Streets will be required to intersect one another at an angle as near to a right angle as is practicable in each case. Where several streets or highways converge at one point, setback lines, special rounding or cut off corners and/or a traffic circle may be required to insure safety and facility of traffic movements. At street intersections the block corners shall be rounded at the property lines by a radius of not less than 20 feet.
(Ord. 447 § 2.1d, April 17, 1956)
All street names shall be subject to the approval of the Planning Commission. Duplication of existing names will not be allowed unless the streets are obviously in alignment with existing streets and not so far removed as to be confusing.
(Ord. 447 § 2.1g, April 17, 1956)
[1]
Name change authorized—See Section 11.04.060 of this Code.
Center line radii shall not be less than 500 feet on highways, except in mountainous areas, where the radii may be reduced to not less than 200 feet, and on all other streets the center line radii shall not be less than 75 feet.
(Ord. 447 § 2.19, April 17, 1956)
Where a subdivision abuts upon a highway of major importance, the Planning Commission may require parallel service roads or may limit the right of access to the highway.
(Ord. 447 § 2.1j, April 17, 1956)
Where a cut or fill road slope extends outside the normal right-of-way of the street, then a slope easement shall be provided of sufficient width to permit maintenance of the slopes by the City.
(Ord. 447 § 2.1k, April 17, 1956)
Alleys may be required in the rear of all prospective business property, except where topography makes the use of alleys impracticable.
(Ord. 447 § 2.2a, April 17, 1956)
Long blocks shall generally be encouraged and they shall be provided adjacent to main thoroughfares for the purpose of reducing the number of intersections; however, blocks shall not exceed 1,200 feet in length unless existing conditions justify a variation from this requirement.
(Ord. 999 § 7, November 15, 1982)
Sidewalks 10 feet in width shall be required along all business street frontage.
Sidewalks four feet in width shall be required along all residential street frontage.
Sidewalks of a width acceptable to the Planning Commission shall also be required through the center of long blocks, to connect cul-de-sac streets, and to provide access to school park and playground areas, and to river, lake, bay and ocean frontages.
Sidewalks may be eliminated on one or both sides of streets where the Planning Commission finds that the slope of the grounds or the nature of the development makes them impractical or inappropriate.
(Ord. 999 § 7, November 15, 1982)
Where there exists on property to be subdivided a residential structure which is nonconforming under the provisions of this Code by reason of an excess number of dwelling units (as defined in Section 20.08.080), said property shall not be further subdivided unless the total number of dwelling units which may result from such subdivision does not exceed the number of dwelling units which would be allowed on the property if all structures thereon conformed to the provisions of this Code.
(Ord. 725 § 1, January 18, 1971)
No lot shall have an average width of less than 50 feet.
No lot shall have an area of less than 6,000 square feet. In any case lots shall conform with the requirements of any zoning ordinance effective for the area in which the proposed subdivision is located. Where property is zoned for business uses, other widths and areas may be permitted at the discretion of the Planning Commission.
(Ord. 447 § 2.5a, April 17, 1956)
In addition to the other provisions of this title, any lot hereafter created as a part of any subdivision shall comply with either the minimum lot size and width provisions of Section 20.16.040 or the minimum land area and width criteria with respect to topography set forth in the following table, whichever are greater. This requirement shall not apply where the proposed subdivision merely results in realignment of existing lot lines and does not create any additional parcels or building sites.
Percent Slope
Minimum Land Area in Square Feet
Minimum Width in Feet
0-10
As specified in Zoning District
 
11-15
10,000 sq. ft.
80
16-20
15,000 sq. ft.
100
21-30
20,000 sq. ft.
150
31-40
43,560/1 acre
200
41-50
2 acres
300
51-60
4 acres
300
61-70
6 acres
300
71-80
8 acres
300
over 80
10 acres
300
For purposes of this section, minimum width is defined as either: the distance between the side lot lines, measured at right angles to the median between the side lot lines, at a point midway between front and rear lot line; or, the dimension on a line parallel to the average direction of the natural contours, passing through the center of an area which, in the opinion of the Planning Commission, would permit the location of a dwelling with the least amount of grading, the safest and most convenient driveway access, and which would otherwise conform to all provisions of this title, and with the intent of this section.
For the purposes of this section, lot slope shall be measured along a line passing through the center of the lot or the building site between lot lines and perpendicular to the natural contours. Percentage slope equals the vertical rise in feet between two points, divided by the horizontal distance between the two points multiplied by 100, and rounded to the nearest full percent.
The Planning Commission may recommend and/or the City Council may amend and authorize conditional exceptions allowing a lot with lesser width and area than required by the percent of slope. Any such exception should be made pursuant to those guidelines outlined in Chapter 21.36, Exceptions, of this title. In addition to those findings set forth therein, the following findings shall be made.
A. 
Demonstrate reasonable and realistic access.
B. 
Indicate minimal disturbance of existing site conditions from new construction.
C. 
Show minimal impact to neighborhood including traffic circulation and public safety.
Nothing contained in this section shall result in a merger of contiguous parcels or units of land under Section 21.04.044 or any other provision of law.
(Ord. 984 § 2, November 2, 1981; Ord. 1093 § 8, March 19, 1990)
Lots shall have a minimum frontage of 35 feet on a street. Further, a lot shall have a width of 55 feet at the building line. For the purpose of this section, the building line will be the required front set back line for the zoning district and not the specific site of the building on the lot.
(Ord. 447 § 2.5b, April 17, 1956; Ord. 631 § 1, April 5, 1965)
Side lines of lots shall be as near as possible to right angles to the street line upon which the lot faces.
(Ord. 447 § 2.5c, April 17, 1956)
Lots other than corner lots having double frontage with depths of less than 200 feet will not be approved except where necessitated by topographic or other physical conditions or where ingress or egress to and from one of the streets is prohibited.
(Ord. 447 § 2.5d, April 17, 1956)
Each lot must have an adequate building site, garage and/or carport location that will not require a variance.
(Ord. 447 § 2.5f, April 17, 1956)
Where parcels of land are subdivided into larger building sites than required by the City zoning ordinance each lot indicated thereon shall be restricted against re-subdivision unless it can be divided in accordance with provisions of this section and other provisions of this title.
(Ord. 447, § 2.5g, April 17, 1956)
The subdivider shall dedicate a right-of-way for storm drainage purposes conforming substantially with the lines of any natural water course or channel, stream or creek that traverses the subdivision, or at the option of the subdivider, provide by dedication, further and sufficient easements, or construction, or both, to dispose of such surface and stormwater.
(Ord. 447, § 2.6, April 17, 1956)
Reserved strips controlling the access to public ways, or which will not prove taxable for special improvements, will not be approved unless such strips are necessary for the protection of the public welfare or of the substantial property rights, or both, and in no case except when the control and disposal of the land comprising such strips is placed definitely within the jurisdiction of the City under conditions approved by the Planning Commission.
(Ord. 447, § 2.7, April 17, 1956)
The Planning Commission may require adequate provisions for suitable areas for parks, playgrounds, schools and other public building sites, as well as such measures as will preserve and enhance the scenic values of the City and the conditions making for excellence of residential, commercial, or industrial developments. Such provision shall not be construed as an obligation of the City for maintenance of such areas as parks or playgrounds.
(Ord. 447 § 2.9, April 17, 1956)
An offer of dedication shall be made to the City of Mill Valley or other appropriate governing bodies of all parcels of land intended and/or designated to be used for public purposes. Such an offer of dedication shall be by certificate on the final map or such other acts as may be appropriate.
(Ord. 447 § 2.11, April 17, 1956)
Where marsh or low lands are proposed for subdivision, the subdivider shall have a soil investigation and recommendation made by a recognized, qualified soil mechanics engineer, and the program for development shall be made on the basis thereof. In no case, however, shall any subdivision be approved which has any street curb grade at an elevation of less than eight feet on the standard mean sea level datum as established by the U.S. Coast and Geodetic Survey, and then only where there is an adequate provision for the passage of stormwater run-off.
(Ord. 447 § 2.12, April 17, 1956)