Disposition Summary

Approve the alternative design standard based on the justification provided by the applicant and the recommendations of the Knox County Department of Engineering and Public Works.

Approve the Concept Plan subject to 9 conditions.

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Staff Recommendation

Approve the alternative design standard based on the justification provided by the applicant and the recommendations of the Knox County Department of Engineering and Public Works.

Approve the Concept Plan subject to 9 conditions.

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1) Connection to sanitary sewer and meeting other relevant utility provider requirements.
2) Provision of street names consistent with the Uniform Street Naming and Addressing System within Knox County (County Ord. 91-1-102), including but not limited to addressing reassignment for the existing residences that will access the new internal roads.
3) Constructing a sidewalk connection to the school property from the Road 'D' cul-de-sac, as shown on the Concept Plan. The sidewalk shall be located in a common area. The design details will be worked out with Knox County Engineering and Public Works during the design plan phase.
4) Providing a Transportation Impact Letter (TIL) for review and approval to Planning and Knox County Engineering and Public Works (EPW) staff during the design plan phase to determine if a westbound left turn lane and eastbound right turn lane on Tipton Station Road are warranted. If warranted, the applicant must enter into a Memorandum of Understanding with Knox County Engineering and Public Works per Chapter 54, Article V of the Knox County Code (Ord. O-23-4-102). The scope of work for the TIL will be provided by Planning and EPW staff to the applicant upon request.
5) Providing the Road 'D' stub-out as shown on the concept plan and providing notification of future connection per section 3.04.C.2 of the Subdivision Regulations. The paved surface of the stub-out can be stopped short of the adjacent property line if determined necessary by Knox County Engineering and Public Works during the design plan phase to more easily allow for connection from the adjacent property in the future.
6) Access must remain open at all times to the properties to the south that utilize the existing 50 ft joint permanent access easement and driveway through the subject property.
7) Providing a sight distance easement on Lot 50 if required by Knox County Engineering and Public Works during the design plan phase.
8) Meeting all applicable requirements of the Knox County Department of Engineering and Public Works.
9) Meeting all applicable requirements of the Knox County Zoning Ordinance.

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The staff report was revised on 10/5/2023 to remove all Subdivision Regulation variance requests based on the Concept Plan revised on 10/4/2023, and adding a second Development Plan condition requiring a Type 'B' landscape screen along the southern boundary of the development.

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This proposal is for a residential subdivision with up to 71 detached houses on individual lots on approximately 20.21 acres (3.51 du/ac). The property was rezoned from A (Agricultural) to PR (Planned Residential) up to 3.7 du/ac in September 2023 (8-F-23-RZ).

ROAD STUB-OUT
The applicant proposes a road stub-out at the southern terminus of Road 'D'. This is also a condition of approval (#5). The concept plan shows the paved road surface extending to the southern boundary of the development. The recommended condition allows Knox County Engineering and Public Works to approve the pavement to stop short of the southern boundary if it will more easily allow the future road connection to tie in.

TRANSPORTATION AND SIDEWALK IMPROVEMENTS
A sidewalk connection is provided from the Road 'D' cul-de-sac to the South-Doyle High School property line. Condition #3 recommends that the sidewalk be located in a common area rather than an easement across lot 20.

Condition #4 requires that the applicant submit a transportation impact letter (TIL) during the design plan phase to evaluate the need for a right or left turn lane on Tipton Station Road. If either is warranted, the applicant must enter into a Memorandum of Understanding with Knox County Engineering and Public Works to install the turn lane(s). A transportation impact study (TIS) was not required for this request because the projected traffic generation is less than 750 vehicle trips per day. However, because the access is so close to a school, staff recommends a limited study examining whether turn lanes are warranted.

ALTERNATIVE DESIGN STANDARDS (Revised 10/5/2023)

Alternative Design Standard #1: When a road is longer than 1,000 ft, the subdivision regulations require the horizontal curve radius to be a minimum of 250 ft. Otherwise, the minimum horizontal curve radius is 100 ft. Road 'B' is 1,050 ft long from its intersection with Road 'D' to its terminus south of its Road 'E' intersection. While the road is longer than 1,000 ft, the road segments on either side of the Road 'A' intersection are significantly less than 1,000 ft. Very little vehicle traffic will travel the full distance of Road 'B'. The proposed 1,000 ft radius is near Road 'A', which is where most traffic will come from, and it is expected that vehicles will still be accelerating and that the sharp turn will naturally keep speeds below the posted 25 mph speed limit through the curve. The minimum horizontal curve radius for AASHTO at 20 mph is 86 ft.