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HomeMy WebLinkAbout102 PZ 24 LUR Road Standards PZC Staff Report 102 PZ 24 PZC LINCOLN COUNTY PLANNING & ZONING COMMISSION STAFF REPORT Land Use Regulation Amendment Proposal REQUEST FOR 30 DAY NOTICE HEARING TIME AND DATE: 6:00 p.m., May 22, 2024 PLANNING & ZONING COMMISSION HEARING TIME AND DATE: July 24, 2024 LOCATION: Lincoln County Courthouse, Commissioner Boardroom 3rd Floor, 925 Sage Ave., Kemmerer, Wyoming & Afton Planning & Development Office, 61 E. 5th Ave., Afton, Wyoming FILE # 102 PZ 24 APPLICANT: Lincoln County Planning & Development Office PROJECT NAME: Land Use Regulations Amendment Road Standards PLANNER: Stephen P. Allen ____________________________________________________________________________________ PROPOSAL: A Proposed Amendment to the Lincoln County Land Use Regulations to modify Road Standards in Chapter 6.16-6.19, 6.11.D.3. and Chapter 7.1, which will address recent development issue and promote safer road design. Proposal A. Modify language in Chapter 6.16 Road Standards Proposal B. Replace Standard Grading Sections Chapter 6.16, Pages 20-21 with Typical Section drawing Proposal C. Add Cul-de-Sac drawing to follow Typical Section drawing in 6.16 Proposal D. Modify language in Chapter 6.17 General Road Design Requirements Proposal E. Amend language and Road Type Table in 6.18 Subdivision Road Design Specifications Proposal F. Amend language in 6.19 Road Right-of-Way Proposal G. Add definitions to Chapter 7.1 Proposal H. Change “Office of Planning & Engineering” to “Office of Planning & Development” throughout the Lincoln County Land Use Regulations Proposal I. Modify Lot Design Specifications, layout to clarify flag lot limitations ___________________________________________________________________________________ ATTACHMENTS: 1. Current Standard Grading Sections Chapter 6 2. Current 6.18 Road Type Table ___________________________________________________________________________________ PLANNING STAFF RECOMMENDATION: Planning Staff recommend that the Planning and Zoning Commission approve a 30-day notice to consider adoption of file # 102 PZ 24 Proposals A. through I. 102 PZ 24 PZC PROPOSAL A: Modify language in Chapter 6.16 Road Construction Standards PROPOSED CHANGES ARE UNDERLINED AND RED, DELETED TEXT IS STRUCK OUT. 6.16 ROAD CONSTRUCTION STANDARDS A. Surface Specification All Subdivision Roads are required to be either graveled or paved. Gravel-- For gravel roads, the minimum acceptable sub-base is eight (8) inches of pit run coarse aggregate; the minimum surface is four (4) inches of crushed coarse aggregate, Wyoming Department of Transportation Grading W or GR. Paved-- For paved roads, the minimum acceptable sub-base is four (4) inches of crushed coarse aggregate; is eight (8) inches of pit run coarse aggregate; the minimum surface is four (4) inches of crushed aggregate; and a the minimum acceptable base is two (2) inches of bituminous pavement. A chip seal or sand and gravel seal-wearing course shall be applied. Gradation/Specification Requirements: Subbase and Base Grading Sieve J GR L K W % Passing 2 in [50 mm] 100 1 ½ in [37.5 mm] 90 to 100 100 100 100 1 in [25 mm] 100 90 to 100 90 to 100 90 to 100 ¾ in [19 mm] 90 to 100 ½ in [12.5 mm] 65 to 85 60 to 85 60 to 85 No. 4 [4.75 mm] 35 to 75 50 to 78 35 to 55 40 to 65 45 to 65 No. 8 [2.36 mm] 30 to 55 33 to 53 No. 200 [75 µm] 0 to 15 4 to 15 3 to 15 3 to 15 3 to 12 102 PZ 24 PZC Aggregate Properties: Subbase and Base Properties Subbase Base Crushed Base Shouldering (Gravel Roads) LA abrasion loss, max., % 50 50 50 Liquid limit, max. 25 25 30 Plasticity index 0 to 6 0 to 3 4 to 12 R-Value, min. 60 75 60 Soundness (MgSO4) loss, max. 18 18 calculated for the combined material, % B. Design, Construction Layout and Survey 1. Structural Section may need additional Engineering based on soil reports. Planning Administration may require the Structural Section be stamped by a Licensed Engineer in the State of Wyoming. 2. Alignment stakes will only may be set for blade and cast sections. 3. Grade stakes will may be set for grade sections. Grade given will may be for finished grade on center-line of roadway. 4. Transitions from crowned sections to curved sections to be made in fifty (50) foot sections on the tangents preceding and following a curve. 5. Temporary monuments of 3/8 inch x 12 inch steel re-bar may be used during construction. 6. Roadways shall be constructed to profiles and cross sections, grade and surfaced in accordance with the standards, rules, and regulations of Lincoln County. Planning Staff may require plan, profile and cross sections be submitted prior to construction. Planning Staff may also require plans to be stamped by a Licensed Engineer in the State of Wyoming. 102 PZ 24 PZC PROPOSAL B: Replace Standard Grading Sections Chapter 6.16, Pages 20-21 with Typical Section drawing (follows) 102 PZ 24 PZC PROPOSAL C: Add Cul-de-Sac drawing to follow Typical Section drawing in 6.16 (follows) 102 PZ 24 PZC PROPOSAL D: Modify language in Chapter 6.17 General Road Design Requirements PROPOSED CHANGES ARE UNDERLINED AND RED, DELETED TEXT IS STRUCK OUT. 6.17 GENERAL ROAD DESIGN REQUIREMENTS A. Subdivision roads should have a loop road for a turnaround point rather than a cul-de-sac unless it is determined by the Office of Planning and Development and Engineering and/or the County Engineer that the physical characteristics of the site prohibit its construction. B. The arrangement of streets in new subdivisions are encouraged to provide for the continuation of streets in adjoining subdivisions and other areas. Road rights-of-way shall be provided from the proposed subdivision roads or streets to adjacent or adjoining lands if such easements or rights-of- way would improve access to the potentially developable lands or potentially landlocked lands and would facilitate the development of a coordinated road system developing within the area. Roads shall be designed and aligned to join with planned or existing roads. C. If the Planning Office approves a subdivision proposes to have an interior road ending in a cul-de- sac (dead end) because of physical characteristics of the site, the road shall have: a. A minimum radius of 60 70 feet (60’ surface radius). b. A maximum length of one thousand (1,000) feet. c. Adequate snow storage shall be provided to keep turnarounds clear. Dead end roads which do not have turnarounds are not allowed. Road design proposals may be reviewed by the County Engineer and/or local fire chief to assist in review for safety and adequacy. D. The Board of County Commissioners shall require, prior to approving a subdivision plat, the rearrangement, deletion or addition of streets, lots and entrances if significant traffic, safety or other hazardous problems exist in a proposed subdivision. E. No lot, of a newly created subdivision, shall be designed to have direct access to a County Road. The construction of a subdivision road is necessary for access for multiple lots. F. Half streets within a subdivision, or along a subdivision boundary, are not permitted. G. All bridges/culverts, serving drainage basins over 200 acres, shall be designed by an registered Engineer licensed in the State of Wyoming. Additionally, all bridges/culverts serving drainage basins under 200 acres may require a licensed Engineer in the State of Wyoming at the discretion of the Planning Administrator. All disturbed areas shall be graded appropriately and re-seeded after construction. 102 PZ 24 PZC H. Access to subdivisions shall be from roads constructed within dedicated public rights-of-way, private road rights-of-way or recorded perpetual easements. Two (2) points of access into the subdivision shall be provided if the proposed subdivision contains 15 or more lots. I. Road design proposals may be reviewed by the County Engineer and/or local Fire Chief to assist in review for safety and adequacy. J. Pedestrian way/bicycle path requirements a. Pedestrian ways and bicycle paths shall have a right-of-way width of ten feet (10’) where in the opinion of the County Commissioners they are necessary for pedestrian circulation within the subdivision or to provide access to common elements. The extent of improvements required for pedestrian ways or bicycle paths shall be considered on an individual basis. Pedestrian ways or bicycle paths of greater or lesser width may be required by the Board of County Commissioners. K. One-way roads: One-way roads will not be allowed. 102 PZ 24 PZC PROPOSAL E: Amend language and Road Type Table in 6.18 Subdivision Road Design Specifications 6.18 SUBDIVISION ROAD AND BRIDGE DESIGN SPECIFICATIONS A. Subdivision Roads All proposed subdivision roads shall be built to the specifications outlined below. The road design standards are designed to accommodate different volumes of traffic. The standards for roads carrying heavier traffic loads are more stringent than for roads carrying fewer automobiles. Each subdivision road shall be designed with the assumption that the subdivision will be fully developed and that each lot will create average daily traffic (ADT) of 11.25 trips. Unit of Average Daily Traffic TYPE UNIT PER UNIT ADT Dwelling, Single Family Per dwelling unit 10 Dwelling, Two Family Dwelling, Multiple-Family Per dwelling unit Per dwelling unit 7 7 Guest House Mobile Home Park Per dwelling unit Per mobile home 5 5 Hotel Storage Units Per room Per unit 9 0.25 Restaurant Per 1,000 S.F. gross 90 Commercial Per 1,000 S.F. gross 115 Office Per 1,000 S.F. gross 11 RV Park Per space 7 Super Market Per 1,000 S.F. gross 102 When per unit average daily traffic (ADT) counts are not listed for a type of development, or an ADT has not been established for a particular category or location by the County Engineer, the design engineer shall use an acceptable reference approved by the County Engineer such as the ITE “Trip Generation Handbook,” current edition, to obtain the appropriate ADT count. Each road shall be designed with the assumption that the subdivision will be fully developed and that each lot will create average daily traffic. 102 PZ 24 PZC Road Type Road type A Private – Collector B Private – Local C Private - Local Number of lots served by road 40 and more 20 to 39 25 to 39 3 to 19 3 to 24 ADT TYP ADT 400+ TYP ADT > 300 to 400 TYP ADT < 300 Minimum Right-of-Way Width (Ft) 60 Travel Way Roadway Width (Ft) 24, 20, 20 26 Shoulder 0,1’ 0,1’2’ 0,1’2’ Surface Type Paved Gravel or Paved Gravel or Paved Design Speed (mph) 45 30 30 Intersections Not less than 84 degrees Not less than 84 degrees Not less than 84 degrees Intersection offset, min. (Ft) * 660 330 125 150 Grades, max. 6%, 8%, 10% ** Grades, min. 0.3 % Crown, min. 0.3% 3% Gravel or 2% Paved Max. Grade 100 ft. before intersection 3 % 4 % Min Horizontal Curve Radius (Ft) 300, 300 500 250, 250, 100 300 250, 250, 100 300 Visibility at Intersection 415 310 210 Min. Stopping Sight Distance (Ft) *** 400 200 200 Signs at intersection Stop Street name Yield or Stop Street name Yield or Stop Street name *Measured from inside edge of ROW **MOUNTAIN TERRAIN – Topography determined by Planning Staff may allow exceptions:  Road shall be designed by a Licensed Engineer in the State of Wyoming  Fewer than 10 lots and shall be less than 99 ADT 102 PZ 24 PZC  GRADE EXCEPTIONS: Exceptions to maximum grades: may have sections with a grade above eight (8) percent and a maximum grade up to ten (10) percent, provided all of the following conditions are met: 1. The section shall be no longer than five hundred (500) feet; 2. The section shall have a horizontal radius of fifteen hundred (1,500) feet or greater; 3. Grades shall not exceed six (6) percent for one hundred and fifty (150) feet on either end of the section; 4. Curves with a horizontal radius of less than three hundred (300) feet shall not be within five hundred (500) feet on either end of the section.  HORIZONTAL CURVE: To be designed no less than a 15-mph curve. Minimum Curve Radius shall not be less than 100 feet. Warning Curve Signs shall be posted in both travel directions a minimum of 100 feet prior to the beginning of a curve with a radius less than 250 feet. (Placement location is dependent on the site conditions) ***Site Distance and Driver’s View 102 PZ 24 PZC If the subdivision is on relatively level terrain (slope not more than 6%) the road design may resemble that of lots and blocks generally found in municipalities. Signs are required to be installed by the applicant at the applicant's expense. The locations of signs are at the discretion of the county staff to promote safe traffic flow and clear communication of information to visitors and emergency service personnel. Signs shall be sturdy, readable and set in concrete. The Planning Office will order signs and posts. They can be picked up at the Planning Office. All signs, striping, markers, delineators, and other traffic control devices shall conform to the requirements of the Manual on Uniform Traffic Control Devices, latest edition, hereinafter referred to as the MUTCD, published by the U.S. Department of Transportation, Federal Highway Administration. B. Bridges General Design Information All structures shall conform to the following: ● AASHTO LRFD Bridge Design Specifications (most current edition and interims) ● WYDOT Bridge Design Manual ● AASHTO Manual for Bridge Evaluation ● WYDOT STANDARD SPECIFICATIONS for Road & Bridge Construction All bridges to be constructed shall be designed by a Professional Engineer who holds a valid license granted by the Wyoming Board of Professional Engineers and Professional Land Surveyors. Submittals ● Design calculations, plans, and specifications shall be submitted ● Load rating for all WYDOT Load Rating Trucks and Emergency Vehicles ● Geotechnical report ● Hydraulic report (if new structure spans a waterway). The report will need to include scour elevations for the design, 100 years, and 500-year events ● Ensure all submittals are stamped by a Wyoming licensed Professional Engineer Design Criteria All structures shall conform to the following design standards: ● Each bridge shall have a minimum freeboard clearance of 18 inches between lowest part of bridge structure and top of existing bank ● Minimum Design Truck: HL-93 ● Minimum clear roadway width between parapets: 26 feet ● Minimum Bridge parapet height: 32 inches ● Minimum Bridge parapet test level: TL-3 ● Minimum Frost Depth to Bottom of Footing: 48 inches 102 PZ 24 PZC Material Properties See material requirements in WYDOT Bridge Design Manual. Utilities Where utility conflicts exist; water, power, telephone, cable TV and gas lines will be relocated as required for construction of the project. Where it is feasible and reasonable to locate utility lines elsewhere, attachment to structures will not be permitted. PROPOSAL F: Amend language in 6.19 Road Right-of-Way 6.19 ROAD RIGHT-OF-WAY No development within County rights-of-way, or road easement is allowed, except by an approved County Road License and shall be removed by the property owner immediately upon discovery. Mailboxes, which may be placed in the County right-of-way but must be placed with no portion of the mailbox coming within five (5) feet of the travel way of the road; and garbage cans, which may be placed on the right-of-way on the day of trash pick-up, but must be placed further than five (5) feet back from the travel way. (Lincoln County, Resolution Restricting the Placing of Obstacles on the Right-of-Way of County Roads, No. 2008-81, Book 3Res Page 572.) PROPOSAL G: Add definitions to Chapter 7.1 7.1 DEFINITIONS ADT – Average Daily Traffic Guest House - A detached dwelling, accessory to a principal dwelling unit, located on the same lot or parcel, and smaller in floor area of living space, which may be used as temporary housing for nonpaying visitors or guests or for rental units of the owners or occupants of the main dwelling on the site. Guest Houses as rental units will be allowed a maximum of 800 square feet of living space on lots up to one (1) acre; a maximum of 1,000 square feet of living space for lots between one (1) and five (5) acres; and a maximum of 1,200 square feet of living space for lots greater than five (5) acres. Only one (1) guest house shall be permitted on a parcel or lot. Loop Road – a road with both terminal points on the same street of origin. PROPOSAL H: Change “Office of Planning & Engineering” to “Office of Planning & Development” throughout the Lincoln County Land Use Regulations. 102 PZ 24 PZC PROPOSAL I: 6.11 Lot Design Specifications A. All lots shall be designed to conform to the existing topography in such a way as to avoid future problems of access, construction and drainage. B. Lots shall function efficiently and safely without overcrowding, given the lot's topography, location, hazards and development's: 1. Utilities 2. Vehicular, pedestrian, and emergency access 3. Parking 4. Small wastewater systems 5. Storage of trash, snow and other items 6. Structures 7. Open space C. A Subdivision development shall be required, as reasonably possible, to be compatible with adjoining and/or surrounding densities and uses in terms of the design, bulk and height of any proposed structures. D. Layout. A single lot shall not be divided by a public road, alley, or another lot. 1. Side lot lines shall be at approximate right angles or radial to road right-of-way lines or center-lines. 2. Each lot shall abut a private street, or private access right-of-way, or dedicated street, and have a minimum of 38 feet of frontage. 3. Flag lot design is discouraged. In no case shall a subdivision have more than 2 flag lots and in no case shall they abut each other. In no case shall the leg (or length) of a flag lot exceed 3 times its width. The leg shall be defined as a narrow section of land that leads to the larger body of a lot. The length of the leg shall be defined as the shortest dimension perpendicular or nearly perpendicular to the width. E. Each lot, which is not served by central sewer systems shall contain within its boundaries a build- able area of at least 15,000 square feet. Build-able area is defined as area free of: slope over 30 percent, avalanche hazard, mine subsidence hazard, stream/river channels, 100- year flood plains, and/or road easements. See Table 6.1 Residential Density Table for minimum lot sizes for new residential subdivision lots.