Salt River Road Extension

City of St. Peters, Missouri


The new four-lane, 5,000-ft-long project included three bridges and a traffic signal at the major intersection of Mid Rivers Mall Drive and Salt River Road. The new roadway is part of a planned east-west arterial roadway connecting Spencer Road and Highway 370 to Highway 79, and will provide for commercial growth in the Premier 370 development area.

Horner & Shifrin designed three bridges over Spencer Creek, Dardenne Creek and Spencer Road as part of the project, which all accommodate four lanes of traffic as well as a 10-foot-wide pedestrian/bicycle trail.

Horner & Shifrin provided an economical, cost effective yet innovative solution by designing a tight diamond interchange that minimized the amount of right-of-way takings. Because this project is included with three other projects that will ultimately extend Salt River Road from Highway 79 to Highway 370, it involved a high degree of coordination with other municipalities, consultants and agencies. Horner & Shifrin was especially vigilant to make sure all project milestones were met and that all parties were kept apprised. The project had a moving target completion date, yet was completed on an accelerated schedule.




Site Size

5,000 ft.


St. Peters, Missouri, Missouri

Year Completed


Innovation. Agility.
Reliability. Horner & Shifrin.