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HomeMy WebLinkAbout06.0 Section 5 Impact and TrafficSECTION 5 Impact and Traffic Impact Analysis 4-203G Traffic Study 4-203L Road Waiver February 26, 2018 David Rasmussen 826 Suite C Hwy 133 Carbondale, CO 81623 Re: Response for Duplex Proposal, Road Waiver for Mountain Shadows Subdivision and Existing Mountain Shadow Drive Road SE Job #17076.01 Dear David, Following Policy 01-14, Sopris Engineering reviewed the Roadway Standards for the proposed internal road, for Mountain Shadows Subdivision with our Road Wavier on May 17th, 2017. The proposed subdivision will now have a final build out of three duplexes. Our pervious letter, for a road wavier used the Institute of Transportation Engineers, (ITE), Trip Generation 7th Edition states to state that single family home has an Average Daily trip of 9.57 per unit. Under the ITE standard ADT's for duplexes is 5.86 per unit. The total number of units for the proposed subdivision is 6, resulting in 36 ADTs. The increase of 7 Average Daily Trips leaves the internal road in the Semi Primitive category of Table 7-107: Roadway Standards. The resulting increase in ADT's will not increase the Roadway standards, thus we request that the Road waiver be modified to reflect the building of Duplexes instead of single family homes. Under the previous Road Wavier approved by the county the existing road currently has 154 ADTs, and an additional 20 ADT's, putting Mountain Shadows Drive into the Rural Access, design standards category of Table 7-107 of the Garfield County Land Use Code, Article 6. The proposed duplexes will only increase the ADT's on the external road from 174 to 181 ADT's. This results in the road staying in the Rural Access Road Category, under Table 7-107. As previously stated in our Road Wavier from May 17th, currently the roadway meets all the designs standards of the county, but the minimum Right -of - Way width. The existing road is platted with a Right of Way of 30'. This has functioned for many years as is and has been adequate for the usage and safety of the roadway. Since the proposed subdivision is not increasing the usage in the next category, being a Secondary Access, we request the county approve the Road Waiver for the building of Duplexes instead of Single Family Homes. If you have any questions or need additional information, please call. Sincerely, SOPRIS ENGINEERING, LLC 6' 46`s • • • ' �ONAL t 4 er h`� Yancy NiailitoPeNinciple 502 Main Street • Suite A3 • Carbondale, CO 81623 • (970) 704-0311 • Fax (970) 704-0313 SOPRIS ENGINEERING • LLC civil consultants ARTICLE 4-203G 1-8 G. Impact Analysis. Where the proposed development will impact specific features of the site, the Applicant shall describe both the existing conditions and the potential changes created by the project. The Impact Analysis shall include a complete description of how the Applicant will ensure that impacts will be mitigated and standards will be satisfied. The following information shall be included in the Impact Analysis: 1. Adjacent Land Use. Existing use of adjacent property and neighboring properties within 1,500 -foot radius. a. Land use to the North: one single-family residence on the north side of Mountain Shadows Drive before it turns into empty mountainside. b. Land use to the West: High density single family residential cluster homes in Chalet Village, medium density single family residences along Creekside Ct, agricultural lands along Mitchell Creek and more mountain side. c. Land use to the South: Directly on the southern property line is a multi -unit property and a single family residence. Off of Donegan Rd there are many multi -unit properties and single family residences. Just to the south of that is a combination of a school, commercial properties such as car dealerships and the mall, mobile home park and government buildings. d. Land use to the East: High to medium density single family homes on lots ranging in size from 0.20-1.0 acres mostly contained in the Western Hills Subdivision. There is also an empty commercial lot that look like a field. e. It should be noted that do to the terrain and vegetation along property lines there is a limited view of the development itself. 2. Site Features. A description of site features such as streams, areas subject to flooding, lakes, high ground water areas, topography, vegetative cover, climatology, and other features that may aid in the evaluation of the proposed development. a. All three lots and buildings will be on a slope of varying degrees with the uphill unit having one floor with a crawlspace below and the downhill unit having a basement below. b. All three lots are south facing with a mix of sun and shade in summer and winter. c. There is very little vegetative cover aside from grass throughout most of all three lots and some trees of mostly smaller trunk size along the western and southern property lines. d. It is not in a flood nor slide zone. e. Reynolds and Cain Ditch Company has a ditch running along the southern property line. Any building will remain outside of this easement. 3. Soil Characteristics. A description of soil characteristics of the site that have a significant influence on the proposed use of the land. a. There is no significant soil characteristics. See Section 3 for Grading and Soil details. 4. Geology and Hazard. A description of the geologic characteristics of the area including any potential natural or manmade hazards, and a determination of what effect such factors would have on the proposed use of the land. a. There is no significant soil characteristics. See Section 3 for Grading and Soil details. 5. Groundwater and Aquifer Recharge Areas. Evaluation of the relationship of the subject parcel to Floodplains, the nature of soils and sub -soils and their ability to adequately support waste disposal, the Slope of the land, the effect of sewage effluents, and the pollution of surface Runoff, stream flow, and groundwater. a. All units on all three lots will connect with the city sewer system b. Two water retention areas are at the southern part of the property before the ditch to help curb runoff. 6. Environmental Impacts. Determination of the existing environmental conditions on the parcel to be developed and the effects of development on those conditions, including: a. Determination of the long-term and short-term effect on flora and fauna; i. With the planning of draught resistant and native plants (where possible) the flora of the lots will be improved. ii. With the development of the lots there is no effect on fauna since the use of the property is ARTICLE 4-203G 1-8 not being changed dramatically from its current state nor impacting the state of neighboring properties. iii. Plants installed will follow city bear guidelines. b. Determination of the effect on designated environmental resources, including critical wildlife habitat; i. There is no impact on environmental resources nor effect on wildlife as it is not in a critical habitat. c. Impacts on wildlife and domestic animals through creation of hazardous attractions, alteration of existing native vegetation, blockade of migration routes, use patterns, or other disruptions; and i. There is no impact on wildlife nor domestic animals. d. Evaluation of any potential radiation hazard that may have been identified by the State or County Health Departments. i. No radiation has been identified by the State nor County Health Department. 7. Nuisance. Impacts on adjacent land from generation of vapor, dust, smoke, noise, glare or vibration, or other emanations. a. None of the above will be generated as the internal road (driveway) will eventually be paved. b. The slope of the lots help with creating a natural privacy and lower profile of any development. 8. Hours of Operation. The Applicant shall submit information on the hours operation of the proposed use. a. To be consistent with residential uses. Article 4-203L — Traffic Analysis Assessment of Traffic Impacts. We do not expect construction of the duplexes in this application to significantly impact local traffic. The proposed size of the duplexes is comparable to single family residences and we do not anticipate construction traffic to be greater than the amount of construction traffic that would be generated by single-family residences. There is ample room on the site for storage and parking. It should also be considered the subdivision (site or property) where work will be done is at the end of a dead end street where very little existing traffic occurs. 1. Study/Analysis a. If the Director determines that any 1 of the following thresholds is exceeded: i. Traffic volumes projected at any intersection when a State or Federal highway exceeds current volumes by 20%, as determined by CDOT using current traffic counts and CDOT-approved methodology; 1. Answer: Not affected ii. Traffic volumes projected on any County road segment exceed current volumes by 20%; 1. Answer: Not affected iii. Traffic volumes on any road segment identified or contained within an approved municipal street plan within a 1 -mile radius exceed current volumes by 30%. 1. Answer: Not affected 2. Basic Traffic Analysis. The Basic Traffic Analysis shall include the following information: a. A map or maps depicting the parcel or activity area and showing the Article 4-203L — Traffic Analysis following information: i. (1) Existing and proposed internal roads, adjoining roads, access points, and access points for the finished development; 1. Answer: See Site Plans Section 2 ii. (2) All County roads within a 1 -mile radius of the development; 1. Answer: CR 136, CR 135, CR 132, CR 130 iii. (3) The nearest proximate intersections with State or Federal highways likely to receive traffic impacts from the development; and 1. Answer: Interstate 70 and State Highway 6 (and 24) is within one mile and will not be affected by the increase created by changing the MSP subdivision lots from SFR to Multi -Family. iv. (4) Activity areas for construction activity. 1. Answer: All construction will take place on MSP. Any disruption to the access easement will be part of the building permits. b. A narrative description of existing land uses on the parcel, including the following information: i. Answer: There is no current use of the land. ii. (1) Current Trip Generation estimates at existing access points; 1. Answer: There is one access point. During the busiest time of development there will be roughly 6 trips a day. Article 4-203L — Traffic Analysis iii. (2) County driveway permits for the access points and status; 1. Answer: Not applicable; access and parking are supplied by the internal road created and approved with the subdivision. iv. (3) Permit requirements for access to a State highway, railroad crossings, and status; 1. Answer: None required v. (4) All access easements and information regarding the legal status of these easements; and 1. Answer: See Section 7 regarding Legal Access vi. (5) Other appropriate current traffic information and legal constraints that may apply. 1. Answer: Not applicable c. A description of the construction of the development, including the following: i. (1) Staging and storage areas; Answer: Storage and staging will be on site. ii. (2) Temporary access points; Answer: Access will be at the existing access point off of the ROW access easement off of Mountain Shadows Drive. iii. (3) Duration, types, and frequency of heavy truck traffic; Answer: 1-2 trucks a day for one month during the site improvements and foundation stage. Article 4-203L — Traffic Analysis iv. (4) Access road segments to be impacted; Answer: The access road will not impacted as the transport of the buildings will be quick, with proper support vehicles, permits and following CDOT regulations. v. (5) Projected lane closures or traffic interruption, and a statement of mitigation measures that will be applied to minimize disruption and damage; and 1. Answer: Only impact will be to the access easement when it goes down to one lane for 4 days while the utilities are trenched under the road. 2. Answer: Contractor will facilitate the flow of local traffic during trenching. vi. (6) All County or State permits that will be required. Answer: To be submitted with the building permits 3. Detailed Traffic Analysis. In addition to the information provided in the Basic Traffic Analysis, the following information shall be provided in a Detailed Traffic Analysis. The Detailed Traffic Analysis must show the highest probable volumes from the proposed uses and densities to be allowed at build -out. The Detailed Traffic Analysis shall include an analysis of the existing and proposed levels of service and shall address adequacy of capacity for the proposed use, and any additional information available and applicable to County roads. a. Access points to and from the development shall be analyzed for AM and PM peak hour use for turning movements to determine the necessity for traffic control and signalization, geometrics including turning lanes and acceleration and deceleration lanes, and signage. i. Answer: The subdivision is off of an access easement at the end of a dead end street. Proper traffic control with flaggers and signage will be in place during required times such as lane closure (if necessary). Article 4-203L — Traffic Analysis b. County Road segments where traffic is expected to increase by over 20% shall be characterized in detail by current level of service, roadway condition and type, lane width, shoulder characteristics and condition, available right-of-way, speed limits, any weight limits, existing safety concerns and considerations, likely increases in maintenance requirements, and status for improvement in the County capital improvements plan. Probable maintenance and improvement cost estimates shall be provided. i. Answer: Traffic is not expected to increase by over 20% c. County road intersections where traffic is expected to increase by over 20% shall be characterized by existing traffic control and signalization, AM and PM peak hour utilization with turning movements, projections for levels of service, and recommended modifications for intersection geometrics, including turning lanes, control or signalization devices, acceleration or deceleration lanes, and advance signage where appropriate. Probable cost estimates shall be provided. i. Answer: Traffic is not expected to increase by over 20% d. State or Federal highway intersections where traffic is expected to increase by over 20% shall be characterized by existing traffic control and signalization, AM and PM peak hour utilization with turning movements, through movements as applicable, projections for levels of service, and recommended modifications for intersection geometrics, including turning lanes, control or signalization devices, acceleration or deceleration lanes, and advance signage. Consultation with the Colorado Department of Transportation is required and shall be documented. Probable cost estimates shall be provided. i. Answer: Traffic is not expected to increase by over 20% 4. Calculation of On -Site and Off -Site Improvements and Fees. a. Answer: See SIA in Section 4 Article 4-203L — Traffic Analysis 5. Additional Submittal Requirements and Documentation. a. Existing County permits, including driveway permits and access permits; i. Answer: Permits to be pulled with building permits b. Existing access easements; i. Answer: See Site Plans and/or Plat in Section 2 c. Existing permits from CDOT, railroads, or other applicable entities; i. Answer: Not applicable d. Evidence of consultation with the County for future access locations; i. Answer: Not applicable but should be noted the County already approved the subdivision and proposed improvement including the road and pertinent road waivers. e. Evidence of consultation with CDOT for future access permits, as applicable; i. Answer: Not applicable f. Any proposed access easements, agreements, and modifications and current status; and i. Answer: See Site Plans in Section 2 g. Any proposed noise barrier or sound wall improvements. i. Answer: Not applicable County Standards for Roads Vs. Existing and Proposed Roads ADT = 5.86 per unit for duplexes* ADT = 9.57 per residence* 15 homes in challet village (143.55 ADT) + Starr Residence (9.57) + 6 proposed units in Mountain Shadow Place subdivision (35.16 ADT) = 188.28 ADTs * ITE standard ADT 181.83 ADTs with subdivison SFR 188.28 ADTs with subdivision 6 Units 6.45 ADT = the increase by approving the duplexes. The increase is less than one SFR. This increase is less than 20% County - Rural Access Road Access Easement County - Semi Primitive Road Proposed Internal Roadway ADT 101-200 172.26 21-100 25.16 (6 Units) Min ROW Width 50' 30' 40' 40' Lane Width 11' 11' 10' 8' Shoulder Width 4' 0 2' 2 Ditch Width 6' n/a 4' n/a Cross Slope 3% n/a 3% 2-3% Shoulder Slope 5% n/a 5% 2-5% Minumum Radius 80' 0 50' 25' Max Grade 12% 5% 12% 10% Surface Gravel Gravel Gravel Gravel * ITE standard ADT 181.83 ADTs with subdivison SFR 188.28 ADTs with subdivision 6 Units 6.45 ADT = the increase by approving the duplexes. The increase is less than one SFR. This increase is less than 20%