Sec. 13-29. - Availability of emergency access.
Sec. 13-30. - Road and driveway surfaces.
Sec. 13-31. - Road and driveway grades.
Sec. 13-32. - Road and driveway horizontal curves and intersections.
Sec. 13-33. - Roadway and driveway structures (bridges).
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. 5905, § I, 11-2-2010; Ord. No. 5373, § 2, 2002; Ord. No. 4905, § 1, 1995.)
Sec. 13-29. - Availability of emergency access.
All buildings shall be accessible to emergency fire equipment by a road or driveway constructed to within one hundred fifty (150) feet 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. All buildings located on slopes of greater than five (5) percent shall also include such additional fire protection measures under Section 13-63, as the county fire chief deems necessary to mitigate access constraints.
(Ord. No. 5905, § I, 11-2-2010; Ord. No. 5373, § 2, 2002; Ord. No. 4905, § 1, 1995.)
Sec. 13-30. - Road and driveway surfaces.
All roads and driveways shall have all-weather driving surfaces. All structural sections shall be constructed so as to meet or exceed the following standards:
(a)
On level areas and grades of less than five (5) percent, roads and driveways shall have a gravel surface. The structural section of the road or driveway shall be at least one (1) foot of compacted Class 2 Aggregate Base.
(b)
On grades of between five (5) percent and ten (10) percent, 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 (1) foot of compacted Class 2 Aggregate Base.
(c)
On grades of greater than ten (10) percent, 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 one (0.2) foot thick. The base portion of the structural section shall be at least five-tenths of one (0.5) foot 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 be not less than 3.5.
(Ord. No. 5905, § I, 11-2-2010; Ord. No. 5373, § 2, 2002; Ord. No. 4905, § 1, 1995.)
Sec. 13-31. - Road and driveway grades.
(a)
No road or driveway shall have a maximum grade in excess of fifteen (15) percent, without the approval of the county fire chief. In granting such approval, the county fire chief 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 (20) percent for distances not exceeding three hundred (300) feet within any one thousand (1,000) feet of road or driveway.
(b)
A vertical curve shall be required for any road or driveway when the algebraic difference in grade exceeds three (3) percent for driveways, and two (2) percent for private roads. The length of any vertical curve shall not be less than fifty (50) feet.
(c)
The maximum surface cross slope shall be five (5) percent 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 (2) percent.
(d)
Turnarounds shall have a maximum longitudinal slope of eight (8) percent. 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 (5) percent.
(Ord. No. 5905, § I, 11-2-2010; Ord. No. 5373, § 2, 2002; Ord. No. 5166 § 1(y), 1999: Ord. No. 4905, § 1, 1995.)
Sec. 13-32. - Road and driveway horizontal curves and intersections.
(a)
No road or driveway shall have a horizontal inside radius of curvature of less than fifty (50) feet. If the roadway or driveway width is less than twenty-four (24) feet, then additional roadway or driveway widths shall be required as follows:
(1)
Four (4) feet of additional width for curves with a horizontal inside radius of fifty (50) feet to one hundred (100) feet and a central angle greater than forty-five degrees; and
(2)
Two (2) feet of additional width for curves with a horizontal inside radius of one hundred (100) feet to two hundred (200) feet 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 chief, where a private road, with a throat width equal to or greater than eighteen (18) feet as measured thirty (30) feet from the edge of pavement, intersects a public road, the edge of pavement radius shall begin with a line a minimum of twelve (12) feet from and parallel to the physical centerline of the public road and a minimum radius of twenty-five (25) feet 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 (24) feet wide.
(c)
Where a private road, with a throat width measuring equal to or greater than twelve (12) feet and less than eighteen (18) feet or a driveway with a throat width equal to or greater than ten (10) feet as measured thirty (30) feet 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 (12) feet from and parallel to the physical centerline of the public or private road and a minimum radius of twenty-five (25) feet 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 (24) feet wide. In lieu of a ten-to-one (10:1) taper connecting private road or driveway to private road only, a radius of forty (40) feet may be used.
(d)
Where a driveway, with a throat width measuring equal to or greater than ten (10) feet and less than eighteen (18) feet as measured thirty (30) feet from the edge of pavement, intersects a private road, the edge of pavement shall be a minimum radius of forty (40) feet. Any driveway with a throat width greater than eighteen (18) feet, as measured thirty (30) feet 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.
(Ord. No. 5905, § I, 11-2-2010; Ord. No. 5373, § 2, 2002; Ord. No. 5166 § 1(z), 1999: Ord. No. 4905, § 1, 1995.)
Sec. 13-33. - Roadway and driveway structures (bridges).
(a)
All roadway 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 HS 20. All roadway and driveway structures shall be constructed pursuant to a valid building permit. All roadway and driveway structures shall be inspected according to the administrative and inspection provisions of the County Building Code.
(b)
All roadway and driveway structures shall have appropriate signing identifying structure capability, including weight and vertical clearance limits, and any one-way road or single traffic lane conditions.
(c)
All roadway bridges having only one (1) traffic lane shall be constructed to provide a minimum unobstructed width of twelve (12) feet, shall provide for unobstructed visibility from one end to the other and shall have turnouts at both ends.
(d)
All driveway structures shall be constructed to provide a minimum of one (1) twelve-foot traffic lane and an unobstructed vertical clearance of fifteen (15) feet along the entire length of the driveway structure. Any driveway structure with a minimum unobstructed width of twelve (12) feet shall not exceed sixty-five (65) feet in length.
(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 (40) feet (bulbs shall be forty (40) feet 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 (60) feet in length. If a stub is used, then the length of the turnaround shall be forty (40) feet, as measured from the roadway or driveway edge. The minimum width of either a hammerhead/T or a stub out shall be equivalent to the roadway 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 (20) feet wide, including the roadway and the turnout, and thirty (30) feet long with a minimum taper of twenty-five (25) feet on each end. The length of the turnout shall be measured along the roadway or driveway centerline.
(Ord. No. 5905, § I, 11-2-2010; Ord. No. 5373, § 2, 2002; Ord. No. 5166 § 1(aa), 1999: Ord. No. 4905, § 1, 1995.)
(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 (25) and shall be constructed to provide a roadway with a minimum of two (2) nine-foot traffic lanes providing two-way traffic flow. 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 (12) feet with turnouts and turnarounds. Spacing of the turnarounds shall be as set forth in the subdivision's conditions of approval. If the subdivision's conditions of approval do not set forth spacing requirements, then turnarounds shall be at a minimum interval of one-thousand three hundred twenty (1,320) feet.
(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 (40) feet (bulbs shall be forty (40) feet 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 (60) feet in length. If a stub is used, then the length of the turnaround shall be forty (40) feet, as measured from the roadway or driveway edge. The minimum width of either a hammerhead/T or a stub out shall be equivalent to the roadway 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 (20) feet wide, including the roadway and the turnout and thirty (30) feet long with a minimum taper of twenty-five (25) feet on each end. The length of the turnout shall be measured along the roadway or driveway centerline.
(Ord. No. 5905, § I, 11-2-2010; Ord. No. 5373, § 2, 2002; Ord. No. 4905, § 1, 1995.)
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 (20) feet and shall be constructed to provide a roadway with a minimum of one (1) twelve-foot traffic lane providing one-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 (500) feet in length shall have a turnout constructed at approximately the midpoint of the road. Any one-way road exceeding one thousand (1,000) feet in length shall also have turnouts constructed approximately every five hundred (500) feet along the entire length of the road.
(d)
No one-way road shall exceed two thousand six hundred forty (2,640) feet in length.
(e)
Any road or driveway structure required to have a turnout, shall have a turnout that is a minimum of twenty (20) feet wide, including the roadway and the turnout and thirty (30) feet long with a minimum taper of twenty-five (25) feet on each end. The length of the turnout shall be measured along the roadway or driveway centerline.
(Ord. No. 5905, § I, 11-2-2010; Ord. No. 5373, § 2, 2002; Ord. No. 4905, § 1, 1995.)
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 (800) feet;
(2)
Parcels zoned for one (1) acre to four and ninety-nine hundredths (4.99) acres - one thousand three hundred twenty (1,320) feet;
(3)
Parcels zoned for five (5) acres to nineteen and ninety-nine (19.99) acres - two thousand six hundred forty (2,640) feet; and
(4)
Parcels zoned for twenty (20) acres or larger - five thousand two hundred eighty (5,280) feet.
All lengths shall be measured from the edge of the roadway 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 (1,320) feet 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 (40) feet (bulbs shall be forty (40) feet 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 (60) feet in length. If a stub is used, then the length of the turnaround shall be forty (40) feet, as measured from the roadway or driveway edge. The minimum width of either a hammerhead/T or a stub out shall be equivalent to the roadway or driveway entering the turnaround.
(Ord. No. 5905, § I, 11-2-2010; Ord. No. 5373, § 2, 2002; Ord. No. 4905, § 1, 1995.)
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 (15) feet along the entire length of the driveway.
(b)
All driveways exceeding one hundred fifty (150) feet in length shall have a turnout constructed at approximately the midpoint of the driveway. Any driveway exceeding eight hundred (800) feet in length shall have turnouts constructed approximately every four hundred (400) feet along the entire length of the driveway.
(c)
All driveways exceeding one hundred fifty (150) feet in length shall have a turnaround constructed at each residential building served by the driveway.
(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 (40) feet (bulbs shall be forty (40) feet 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 (60) feet in length. If a stub is used, then the length of the turnaround shall be forty (40) feet, as measured from the roadway or driveway edge. The minimum width of either a hammerhead/T or a stub out shall be equivalent to the roadway or driveway entering the turnaround.
(Ord. No. 5905, § I, 11-2-2010; Ord. No. 5373, § 2, 2002; Ord. No. 5166 § 1(bb), 1999: Ord. No. 4905, § 1, 1995.)
(a)
All gate entrances and similar structures shall be at least two (2) feet wider than the width of the traffic lane(s) serving the gate or structure.
(b)
All gates providing access from a public road to a private road or private driveway shall be located at least thirty (30) feet from the roadway and shall open to allow a vehicle to stop without obstructing traffic on the roadway.
(c)
Where a gated entrance is locked, a lock box or other emergency release device approved by the county fire chief shall be provided for emergency access.
(Ord. No. 5905, § I, 11-2-2010; Ord. No. 5373, § 2, 2002; Ord. No. 4905, § 1, 1995.)