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Traffic Alert: SW Terwilliger and Highway 43 Work Update

March 31, 2017

  • Beginning Tuesday, April 4 crews will implement lane restrictions to Highway 43, between SW Terwilliger Blvd and E Avenue. One lane will be open in each direction at all times.
  • Lane restrictions will be in place 24 hours a day, seven days a week, for up to two months to complete the highway phase as safely and efficiently as possible.
  • Highway 43 will be reduced to one northbound lane and one southbound lane (see map). Work will take up to two months in order to install and connect the sewer under Highway 43.
  • Traffic delay are expected. Please use caution and follow the directions of flaggers.
  • Beginning Monday, April 3, SW Terwilliger Blvd between SW Iron Mountain Rd and SW Northgate Avewill be reduced to one lane 24 hours a day for two weeks. During that time, crews will use special equipment to stabilize the soupy soils along this stretch of road. Flaggers will work 24 hours a day to maintain safe access for local travelers. SW Terwilliger Blvd between SW Iron Mountain Rd and SW Northgate Ave will remain closed to all access except for local traffic.
  • Visitors of Tryon Creek State Natural Area are considered local access on SW Terwilliger Blvd.
  • As a reminder, SW Terwilliger Blvd south of SW Castleridge Ln remains closed to all traffic. Only construction crews may access SW Terwilliger between Highway 43 and SW Castleridge. (see SW Terwilliger detour map)
  • Beginning the first week of April, sewer crews will install manholes on Highway 43.

Environmental Services continues construction on a project to install 7,600 feet of eight-inch sewer in Terwilliger Boulevard from SW Northgate Avenue to Highway 43. Crews will install one 48-inch manhole, one 60-inch manhole, and about 80 feet of pipe in Highway 43 between SW Terwilliger Blvd and SW E Avenue. The new Terwilliger sewer will connect to the 30-inch Tryon Interceptor sewer, which carries sewage to the Tryon Creek Wastewater Treatment Plant in Lake Oswego. This improvement to the wastewater collection system will help protect water quality, public health, and our environment.

For progress photos, additional information, and maps, visit


With questions or comments, please contact Ashley Tjaden, 503-823-5281.