Sonoma County Municipal Code § 13-28 Intent

This division establishes minimum emergency access requirements to provide safe access for emergency fire equipment and civilian evacuation concurrently, and to allow unobstructed traffic circulation during a wildfire emergency.

(Ord. No. 6318, § I, 8-11-2020)

All buildings shall be accessible to emergency fire equipment by a road or driveway constructed to within one hundred fifty feet (150') of any portion of an exterior wall of the first story of the building or such closer distance as the Director of Permit and Resource Management deems necessary to provide adequate access for emergency fire equipment.

(Ord. No. 6318, § I, 8-11-2020)

State Law reference— California Code of Regulations, Title 14 Natural Resources Code, Division 1.5, Chapter 7, Subchapter 2, Article 1-5, SRA Fire Safe Regulations, 1273.00.

All roads and driveways shall have all-weather driving surfaces. All structural sections shall be constructed so as to support a minimum of seventy-five thousand (75,000) pounds or exceed the following standards:

(a) On level areas and grades of less than five percent (5%), roads and driveways shall have a gravel surface. The structural section of the road or driveway shall be at least one foot (1') of compacted Class 2 Aggregate Base.

(b) On grades of between five percent (5%) and ten percent (10%), roads and driveways shall have a double seal coat surface. The structural section of the road or driveway shall have an armor coat surface, constructed according to CalTrans Standard Specifications Section 37 Bituminous Seal Double Application, and the base portion of the road or driveway shall be at least one foot (1') of compacted Class 2 Aggregate Base.

(c) On grades of greater than ten percent (10%), roads and driveways shall have an asphalt concrete surface. The structural section of the road or driveway shall be asphalt concrete of at least two-tenths of a foot (0.2') thick. The base portion of the structural section shall be at least five tenths of a foot (0.5') of compacted Class 2 Aggregate Base.

(d) In lieu of the prescriptive structural sections required by subsections (a), (b) and (c), a design of the section may be prepared by a licensed civil engineer using a soils investigation that provides soil R-value and expansion index. Alternatively, the engineer may use an R-value of 5 and waive the soil report unless a soil engineering report is required because of specific site conditions. The traffic index to be used for the design shall not be less than 3.5.

(Ord. No. 6318, § I, 8-11-2020)

State Law reference— California Code of Regulations, Title 14 Natural Resources Code, Division 1.5, Chapter 7, Subchapter 2, Article 1-5, SRA Fire Safe Regulations, 1273.02.

(a) No road or driveway shall have a maximum grade in excess of sixteen percent (16%), without the approval of the county fire warden/fire marshal. In granting such approval, the county fire warden/fire marshal may require such additional fire protection measures under Section 13-63 as he or she deems necessary to mitigate access constraints. A road or driveway may include grades up to twenty percent (20%) unless sufficient grade reductions are provided to allow for vehicle cool down period as approved by the fire code official.

(b) A vertical curve shall be required for any road or driveway when the algebraic difference in grade exceeds three percent (3%) for driveways, and two percent (2%) for private roads. The length of any vertical curve shall not be less than one hundred feet (100').

(c) The maximum surface cross slope shall be five percent (5%) for all surface types unless a greater cross slope is required to meet super elevation requirements. The minimum surface cross slope for all surface types shall be two percent (2%).

(d) Turnarounds shall have a maximum longitudinal slope of eight percent (8%). The longitudinal slope is defined as the slope corresponding to the long axis of a vehicle as it travels into, out of, and through a turnaround. This slope shall be maintained beginning and ending at the point of tangency of the edge of pavement curves for the turnaround. The cross slope perpendicular to the longitudinal slope shall not exceed five percent (5%).

(e) Fire apparatus cool down areas shall have a minimum width of twenty-two feet wide (22') and thirty feet (30') long with a minimum taper of twenty-five feet (25') on each end. The length of the turnout shall be measured along the road or driveway centerline. Cool down area shall be provided with minimum curves set in Section 13-32 and shall be located on a maximum grade not exceeding five percent (5%). Cool down turnout shall not be allowed on the inside of the horizontal curves without approval of the fire code official.

(Ord. No. 6318, § I, 8-11-2020)

State Law reference— California Code of Regulations, Title 14 Natural Resources Code, Division 1.5, Chapter 7, Subchapter 2, Article 1-5, SRA Fire Safe Regulations, 1273.03, 1273.04

(a) No road or driveway shall have a horizontal inside radius of curvature of less than fifty feet (50'). An additional surface width of four (4) feet shall be added to curves of fifty (50) through one hundred (100) feet radius; two (2) feet to those from one hundred (100) through two hundred (200) feet. The length of vertical curves in roads, exclusive of gutters, ditches and drainage structures designed to hold or divert water, shall not be less than one hundred feet (100'). If the road or driveway width is less than twenty-four feet (24'), then additional road or driveway widths shall be required as follows:

(1) Four feet (4') of additional width for curves with a horizontal inside radius of fifty feet (50') to one hundred feet (100') and a central angle greater than forty-five (45) degrees; and

(2) Two feet (2') of additional width for curves with a horizontal inside radius of one hundred feet (100') to two hundred feet (200') and a central angle greater than forty-five (45) degrees.

The road shall have the full width widening beginning at the point of tangency of the curve requiring the widening to the end point of tangency of that curve or subsequent curves requiring widening (if reverse curves are used). A five-to-one (5:1) taper shall be used to transition from the base width into and out of the widened width.

(b) Unless otherwise approved by the county fire warden/fire marshal, where a private road, with a throat width equal to or greater than eighteen feet (18') as measured thirty feet (30') from the edge of pavement, intersects a public road, the edge of pavement radius shall begin with a line a minimum of twelve feet (12') from and parallel to the physical centerline of the public road and a minimum radius of twenty-five feet (25') shall be provided from this point to the point of tangency with the edge of pavement of the private road. A taper of not less than ten-to-one (10:1) shall be provided along the public road when the public road is less than twenty-four feet (24') wide.

(c) Where a private road, with a throat width measuring equal to or greater than twelve feet (12') and less than eighteen feet (18') or a driveway with a throat width equal to or greater than ten feet (10') as measured thirty feet (30') from the edge of pavement, intersects a public or private road, the edge of pavement radius shall begin with a line a minimum of twelve feet (12') from and parallel to the physical centerline of the public or private road and a minimum radius of twenty-five feet (25') shall be provided from this point to the point of tangency with the edge of pavement of the private road or driveway. A taper of not less than ten-to-one (10:1) shall be provided along the public or private road when the public or private road is less than twenty-four feet (24') wide. In lieu of a ten-to-one (10:1) taper connecting private road or driveway to private road only, a radius of forty feet (40') may be used.

(d) Where a driveway, with a throat width measuring equal to or greater than ten feet (10') and less than eighteen feet (18') as measured thirty feet (30') from the edge of pavement, intersects a private road, the edge of pavement shall be a minimum radius of forty feet (40'). Any driveway with a throat width greater than eighteen feet (18'), as measured thirty feet (30') from the edge of the pavement, that intersects a private road, shall comply with the private road/public road requirements set forth in subsection (b) of this section.

(e) Road and driveway horizontal curves and intersections may be reduced when proven by scientific method of a recognized vehicle modeling program. The method shall be performed based on the length, width, wheel base and turning radius of a standard Type 1 Fire Apparatus.

(f) Turnouts shall not be located in a horizontal curve unless additional width is provide. Width shall exceed the minimums set in subsection (a) in addition to the minimum width of the required turnout.

(Ord. No. 6318, § I, 8-11-2020)

State Law reference— California Code of Regulations, Title 14 Natural Resources Code, Division 1.5, Chapter 7, Subchapter 2, Article 1-5, SRA Fire Safe Regulations, 1273.02.

(a) All road and driveway structures shall be designed, constructed, and maintained in accordance with applicable sections of the county building code, the standard specifications for highway bridges, and any administrative regulations adopted pursuant to Section 13-2, and shall have a minimum designed live-load capacity of HB-17. All road and driveway structures shall be constructed pursuant to a valid building permit. All road and driveway structures shall be inspected according to the administrative and inspection provisions of the county building code.

(b) All road and driveway structures shall have appropriate signing identifying structure capability, including weight and vertical clearance limits, installation and certification date and any one-way road or single traffic lane conditions.

(c) All road and driveway structures having only one (1) traffic lane shall be constructed to provide a minimum unobstructed width of twelve feet (12') and an unobstructed vertical clearance of fifteen feet (15') along the entire length of the structure. It shall provide for unobstructed visibility from one (1) end to the other and shall have turnouts at both ends. Any structure with a minimum unobstructed width of twelve feet (12') shall not exceed sixty-five feet (65') in length.

(d) All structures not meeting subsection (c), shall be constructed to provide a minimum traffic lane as required in other sections of this code and an unobstructed vertical clearance of fifteen feet (15') along the entire length of the structure.

(e) Any road or driveway structure required to have a turnaround may have either a hammerhead/T, a stub out, or terminus bulb. All turnarounds shall have a minimum turning radius of forty feet (40'), bulbs shall be forty feet (40') from the center point of the bulb, hammerhead/T and stub out shall have entry and exit curves of no less than a forty-foot radius. If a hammerhead/T is used, the top of the "T" shall be a minimum of sixty feet (60') in length. If a stub is used, then the length of the turnaround shall be forty feet (40'), as measured from the road or driveway edge. The minimum width of either a hammerhead/T or a stub out shall be equivalent to the road or driveway entering the turnaround.

(f) Any road or driveway structure required to have a turnout, shall have a turnout that is a minimum of twenty-two feet (22') wide, including the road and the turnout, and thirty feet (30') long with a minimum taper of twenty-five feet (25') on each end. The length of the turnout shall be measured along the road or driveway centerline.

(g) All new bridge structures shall meet a minimum standard of HS-20 and be of non-combustible construction unless approved by the building and fire code official.

(h) All existing private bridges and elevated surfaces that are a part of the fire department access road shall be evaluated by a California licensed civil engineer experienced in structural engineering or a California licensed structural engineer, for safety and weight rating, in accordance with American Association of State Highway and Transportation Officials (AASHTO) Manual: "The Manual for Bridge Evaluation," Second Edition, or other approved standard. Vehicle load limits shall be posted at both entrances to bridges. All bridges and elevated structures providing fire department access shall be inspected or maintained when directed by the fire code official.

(Ord. No. 6396, § II, 12-6-2022; Ord. No. 6318, § I, 8-11-2020)

State Law reference— California Code of Regulations, Title 14 Natural Resources Code, Division 1.5, Chapter 7, Subchapter 2, Article 1-5, SRA Fire Safe Regulations, 1273.07.

(a) In addition to meeting the applicable standards in the preceding sections, all two-way roads shall have a right-of-way of not less than twenty-five feet (25') and shall be constructed to provide a road with a minimum of two (2) ten-foot traffic lanes providing two-way traffic flow.

Exceptions:

1. If the two-way road serves a minor subdivision (subdivided into four parcels or fewer) in compliance of Chapter 25 and when permitted in a subdivision's conditions of approval and approved by the appropriate county departments, as identified in the subdivision's conditions of approval, the subdivision may have a two-way road of not less than twelve feet (12') with two-foot (2') shoulders on each side and turnouts and turnarounds. Spacing of the turnarounds and turnouts shall be as set forth in the subdivision's conditions of approval.

a. If the minor subdivision's conditions of approval do not set forth spacing requirements, then turnarounds shall be at a minimum interval of one thousand three hundred and twenty feet (1,320'). Turnouts shall be a minimum of five hundred feet (500') and shall not be located on the inside of horizontal curves without approval from the fire code official.

b. The fire code official is authorized to request the installation of turnarounds and turnouts as part of a development approval at locations necessary to provide two-way traffic flow.

c. A minimum of six feet (6') clear space on one (1) side of the road shall be provided per Chapter 25 of the Sonoma County Subdivision Ordinance Section 25-40(j)(3).

(b) Any road or driveway structure required to have a turnaround may have either a hammerhead/T, a stub out, or terminus bulb. All turnarounds shall have a minimum turning radius of forty feet (40') (bulbs shall be forty feet (40') from the center point of the bulb, hammerhead/T and stub out shall have entry and exit curves of no less than a forty-foot radius). If a hammerhead/T is used, the top of the "T" shall be a minimum of sixty feet (60') in length. If a stub is used, then the length of the turnaround shall be forty feet (40'), as measured from the road or driveway edge. The minimum width of either a hammerhead/T or a stub out shall be equivalent to the road or driveway entering the turnaround.

(c) Any road or driveway structure required to have a turnout shall have a turnout that is a minimum of twenty-two feet (22') wide, including the road and the turnout and thirty feet (30') long with a minimum taper of twenty-five feet (25') on each end. The length of the turnout shall be measured along the road or driveway centerline.

(Ord. No. 6318, § I, 8-11-2020)

State Law reference— California Code of Regulations, Title 14 Natural Resources Code, Division 1.5, Chapter 7, Subchapter 2, Article 1-5, SRA Fire Safe Regulations 1273.01, 1273.05, 1273.06.

In addition to meeting the applicable standards in the preceding sections, all one-way roads shall comply with the following requirements:

(a) All one-way roads shall have a right-of-way of not less than twenty five feet (25') and shall be constructed to provide a road with a minimum of one (1) twelve-foot traffic lane and one-foot shoulders on each side providing one-way traffic flow. The Fire Code Official is authorized to request the installation of turnouts as part of a development approval at locations necessary to provide two-way traffic flow.

(b) All one-way roads shall connect to a two-way road at both ends, and shall provide access to an area zoned for no more than ten (10) dwelling units.

(c) All one-way roads exceeding five hundred feet (500') in length shall have a turnout constructed at approximately the midpoint of the road. Any one-way road exceeding one thousand feet (1,000') in length shall also have turnouts constructed approximately every five hundred feet (500') along the entire length of the road.

(d) No one-way road shall exceed two thousand six hundred forty feet (2,640') in length.

(e) Any road or driveway structure required to have a turnout, shall have a turnout that is a minimum of twenty-two feet (22') wide, including the road and the turnout and thirty feet (30') long with a minimum taper of twenty-five feet (25') on each end. The length of the turnout shall be measured along the road or driveway centerline.

(Ord. No. 6318, § I, 8-11-2020)

State Law reference— California Code of Regulations, Title 14 Natural Resources Code, Division 1.5, Chapter 7, Subchapter 2, Article 1-5, SRA Fire Safe Regulations, 1273.01, 1273.05, 1273.06.

In addition to meeting the applicable standards in the preceding sections, all dead-end roads shall comply with the following requirements:

(a) All dead-end roads shall have a maximum length, including any dead-end roads accessed from the original dead-end road, not exceeding the following cumulative lengths regardless of the number of parcels served:

(1) Parcels zoned for less than one (1) acre — eight hundred feet (800');

(2) Parcels zoned for one (1) acre to four and ninety-nine hundredths (4.99) acres — one thousand three hundred twenty feet (1,320');

(3) Parcels zoned for five (5) acres to nineteen and ninety-nine hundredths (19.99) acres — two thousand six hundred forty feet (2,640'); and

(4) Parcels zoned for twenty (20) acres or larger — five thousand two hundred eighty feet (5,280').

All lengths shall be measured from the edge of the road at the intersection that begins the dead-end road to the farthest point on the dead-end road. Where a dead-end road crosses areas of differently zoned parcels, requiring different length limits, the average size of the parcels served shall determine the maximum allowable length of the road.

(b) All dead-end roads serving parcels five (5) acres or larger shall have turnarounds constructed approximately every one thousand three hundred twenty feet (1,320') along the entire length of the road.

(c) All dead-end roads shall have a turnaround constructed at the terminus of the road. Any road or driveway structure required to have a turnaround may have either a hammerhead/T, a stub out, or terminus bulb. All turnarounds shall have a minimum turning radius of forty feet (bulbs shall be forty feet (40') from the center point of the bulb, hammerhead/T and stub out shall have entry and exit curves of no less than a forty-foot radius). If a hammerhead/T is used, the top-of the "T" shall be a minimum of sixty feet (60') in length. If a stub is used, then the length of the turnaround shall be forty feet (40'), as measured from the road or driveway edge. The minimum width of either a hammerhead/T or a stub out shall be equivalent to the road or driveway entering the turnaround.

(Ord. No. 6318, § I, 8-11-2020)

State Law reference— California Code of Regulations, Title 14 Natural Resources Code, Division 1.5, Chapter 7, Subchapter 2, Article 1-5, SRA Fire Safe Regulations, 1273.05, 1273.08.

In addition to meeting the applicable standards in the preceding sections, all driveways shall comply with the following requirements:

(a) All driveways shall be constructed to provide a minimum of one (1) twelve-foot traffic lane and an unobstructed vertical clearance of fifteen feet (15') along the entire length of the driveway.

(b) All driveways exceeding one hundred fifty feet (150') in length shall have a turnout constructed at approximately the midpoint of the driveway. Any driveway exceeding eight hundred feet (800') in length shall have turnouts constructed approximately every four hundred feet (400') along the entire length of the driveway. Driveways required to have a turnout, shall have a turnout that is a minimum of twenty-two feet (22') wide, including the road and the turnout and thirty feet (30') long with a minimum taper of twenty-five feet (25') on each end. The length of the turnout shall be measured along the road or driveway centerline and shall not be located on the inside of horizontal curves without approval from the fire code official.

(c) All driveways exceeding one hundred fifty feet (150') in length shall have a turnaround. All driveways exceeding three hundred feet (300') shall have the turnaround constructed within fifty feet (50') of the residential building served by the driveway and shall have additional space provided for parking. Any driveway longer than one thousand three hundred twenty feet (1,320') shall have additional turnarounds located at intervals no less than one thousand three hundred twenty feet (1,320') unless approved by the county fire warden/fire marshal. Parking shall not be allowed in the approved turnaround location

(d) Any road or driveway structure required to have a turnaround may have either a hammerhead/T, a stub out, or terminus bulb. All turnarounds shall have a minimum turning radius of forty feet (bulbs shall be forty feet (40') from the center point of the bulb, hammerhead/T and stub out shall have entry and exit curves of no less than a forty-foot radius). If a hammerhead/T is used, the top of the "T" shall be a minimum of sixty feet (60') in length. If a stub is used, then the length of the turnaround shall be forty feet (40'), as measured from the road or driveway edge. The minimum width of either a hammerhead/T or a stub out shall be equivalent to the road or driveway entering the turnaround.

(Ord. No. 6318, § I, 8-11-2020)

State Law reference— California Code of Regulations, Title 14 Natural Resources Code, Division 1.5, Chapter 7, Subchapter 2, Article 1-5, SRA Fire Safe Regulations, 1273.01 12730.5, 1273.06.

(a) All new and rebuilt gate entrances and similar structures shall be at least two feet (2') wider than the width of the traffic lane(s) serving the gate or structure.

Exception:

(1) All existing gate entrances shall conform to Section 13-38(a) when the width of an existing road or driveway is increased.

(b) All gates providing access from a public road to a private road or private driveway shall be located at least thirty feet (30') from the road and shall open to allow a vehicle to stop without obstructing traffic on the road.

(c) Where a gated entrance is locked, a lock box or other emergency release device approved by the county fire warden/fire marshal shall be provided for emergency access.

(d) All new gates installed on private roads where the distance from the gate to the intersection of a public or private road is greater than three hundred feet (300') shall be provided a turnaround in a location approved by the fire code official. All turnarounds shall have a minimum turning radius of forty feet (40') (bulbs shall be forty feet (40') from the center point of the bulb, hammerhead/T and stub out shall have entry and exit curves of no less than a forty-foot radius). If a hammerhead/T is used, the top of the "T" shall be a minimum of sixty feet (60') in length. If a stub is used, then the length of the turnaround shall be forty feet (40'), as measured from the road or driveway edge. The minimum width of either a hammerhead/T or a stub out shall be equivalent to the road or driveway entering the turnaround.

(Ord. No. 6318, § I, 8-11-2020)

State Law reference— California Code of Regulations, Title 14 Natural Resources Code, Division 1.5, Chapter 7, Subchapter 2, Article 1-5, SRA Fire Safe Regulations, 1273.09