I‑485, one of North Carolina’s busiest corridors, carries nearly 135,000 vehicles a day around the Charlotte metropolitan area. As growth accelerated and travel speeds declined, the North Carolina Department of Transportation advanced a major design‑build widening program to relieve congestion and improve safety. The nine‑mile project expanded I‑485 from a four‑lane facility to a combination of six‑ and eight‑lane sections between Rea Road and I‑77. STV served as the design lead, delivering a comprehensive package of roadway, structural, environmental and coordination services to support the region’s long‑term mobility needs.
What challenges did STV address?
The corridor experienced heavy peak‑hour congestion, limited capacity and operational constraints. The widening required integrating new lanes, reconstructing ramps and coordinating with utilities, environmental resources and an active railroad. Stormwater, drainage and foundation design also demanded careful attention due to the project’s surrounding development and varied terrain. Maintaining traffic throughout construction added complexity in an already overloaded corridor.
What solutions did STV deliver?
STV provided full roadway and structural design, stormwater and drainage engineering, pavement and foundation design and environmental planning for the nine‑mile segment. The firm designed three sound barrier walls, developed traffic control plans and coordinated utilities and railroads to keep the project moving efficiently. STV also supported permitting and NEPA compliance and worked closely with the design‑build team to resolve challenges and maintain schedule.
How does this project benefit the community?
The widened interstate eases congestion, reduces travel times and improves safety for commuters and freight carriers. The added capacity supports regional economic growth, enhances access to key employment centers and strengthens the transportation network serving greater Charlotte.
Key stats and accolades
- 135,000 average daily vehicles
- Nine miles widened to six‑ and eight‑lane sections
- Three sound barrier walls designed
- Comprehensive roadway, structural, drainage and environmental services
