what we do

Roadway and Highway Design

Designing infrastructure to safely and efficiently move people and goods

Providing safe and efficient roads and highways is more challenging today due to limited funding and increasingly complex regulatory processes. Parametrix works with clients to develop solutions that are cost effective and minimize disruption to users and the environment. We incorporate LID, green streets, and complete streets principles to create appealing, safe, and sustainable transportation right-of-ways.

US 12 and 21st Street Intersection
US 12 and 21st Street Intersection
Lewiston, Idaho
Client: ITD

The intersection of US 12 and 21st Street serves as a gateway to downtown Lewiston and is an important regional trucking route. The existing multi-leg intersection was realigned to improve safety and traffic flow at the busiest intersection in Central Idaho. The realigned intersection is a standard four-approach intersection with two traffic lanes in each direction, dual left-turn lanes, and designated right-turn lanes. Concrete pavement will help the intersection resist wear from heavier traffic. The intersection features widened sidewalks on the east side of 21st Street and a signal-controlled crosswalk from 21st Street and a park. A new, larger storm sewer trunkline was also installed through a partnership with the City of Lewiston. Parametrix was the prime consultant for the project.

  • President’s Transportation Award – Highways, AASHTO


  • VIEW OUR ROADWAY & HIGHWAY DESIGN PROJECTS

    • US 12 and 21st Street Intersection

      US 12 and 21st Street Intersection

    • Mogollon Reconstruction | Parametrix

      NM 159 Drainage and Roadway Reconstruction

    • Idaho 16, US 20/26 | Parametrix

      Idaho 16, US 20/26 to Idaho 44

    • Pacific Avenue Improvements | Parametrix

      Pacific Avenue Improvements

    • Powell Butte Highway Roundabout | Parametrix

      Powell Butte Highway Roundabout

    • I-5 Mounts Road to Thorne Lane

      I-5 Mounts Road to Thorne Lane Improvements