The offset intersection of Scotch Church and Meek Roads at Jackson School Road in Washington County was overcapacity during peak periods and had a high crash rate with many serious and fatal crashes.
The County selected Murraysmith to complete an alternatives analysis evaluating four options that included signals, different alignment geometries, and a roundabout, which was ultimately deemed the best safety option. Due to the rural setting, the team needed to design a roundabout that would handle large agricultural vehicles and small passenger vehicles, as well as minimize traffic disruption during construction.
To minimize disruption and increase mobility, Murraysmith designed and constructed the roundabout offline from the existing roadways. The team optimized the roundabout geometry using chicanes, which allow for large-vehicle access while still controlling the entry speed of smaller vehicles. To further improve durability and performance, Murraysmith designed a concrete pavement section where vehicle turning has the greatest impact. Designs also included planning for future widening of Jackson School Road between the roundabout and the US26 interchange to the north, where the roundabout could be expanded from one to two lanes. The project required close coordination with ODOT to accommodate the existing interchange access management plan at US26.
Murraysmith led the preliminary project work, including wetlands delineations and mitigation, cultural resource investigations, and development of a comprehensive stormwater management plan to support the Joint Permit Application (JPA) for the US Army Corps of Engineers and Department of State Lands. The completed project dramatically improves safety and capacity of the road and is designed to accommodate future growth in the area.
- Expandable roundabout design
- Over-dimension agricultural vehicles
- ODOT coordination/approvals
- Chicanes to manage high-speed approaches
- Off-line construction to minimize traffic disruptions
- Complex roadway modeling with cuts and fills
- DSL/Corp permitting with SLOPES V compliance
- Sub-regional stormwater management facilities
- Right-of-way acquisition
Willamalane Parks and Rec District
City of Lake Oswego
City of Sherwood