As part of the Kentucky Transportation Cabinet’s (KYTC) Mountain Parkway Expansion, a 45‑mile initiative to improve mobility in Eastern Kentucky, STV delivered comprehensive surveying, civil, structural and geotechnical engineering design services for a 4.6‑mile mainline section of KY 9009 in western Magoffin County. The project widens the Parkway from two to four lanes with a 40‑foot depressed median, providing safer travel, improved access and a modernized corridor that supports long‑term regional growth.
What challenges did STV address?
The most complex portion of the segment involved the “Kernie Cut,” a 180‑foot rock cut that required significant benching and advanced geometrics to ensure safe grades, sight distances and drainage. The corridor’s rugged terrain required extensive side‑hill design, management of approximately 4.6 million cubic yards of rock excavation and careful evaluation of multiple horizontal and vertical alignment options. KYTC’s later decision to widen the environmental footprint required STV to revisit and restudy alignments to maintain cost efficiency.
What solutions did STV deliver?
STV evaluated five design alternatives at 60, 65 and 70 mph, as well as 5 percent and 6 percent grade scenarios and a potential bifurcated configuration. A matrix comparison assessed earthwork, right‑of‑way needs, relocations and environmental impacts, enabling KYTC to select a preferred alternative with the best balance of safety, cost and constructability. STV also performed a comprehensive interchange study to determine optimal placement for a new grade‑separated rural diamond interchange. When the footprint was widened, STV developed a new alignment study that delivered an estimated $40 million in savings.
How does this project benefit the community?
The expanded Parkway strengthens mobility and safety for residents, freight carriers and visitors traveling through Eastern Kentucky. The wider roadway, improved geometrics and new interchange support economic development, reduce travel times and enhance long‑term connectivity across the region.
Key stats and accolades
- 4.2 miles of mainline roadway
- Five alignment alternatives evaluated
- 4.6 million cubic yards of rock excavation
- New rural diamond interchange study
- $40 million estimated cost savings
