Kent drivers can expect long delays along South 277th Street between State Route 167 and Interstate 5 from July 26 through November due to the replacement of a 70-year-old bridge.

South 277th Street will be reduced to one lane in both directions near the project, which is just west of 68th Avenue South and south of Carpinito Brothers Farm in the Green River Valley. South 277th Street is a four-lane road that connects I-5 to SR 167 in Kent and Federal Way.

Due to high average daily traffic on South 277th, and unfavorable detour routes, the existing bridge will remain open with travel lane reductions through the construction zone.

This King County Road Services Division project replaces a 16-foot-long bridge over Mullen Slough with a four-sided concrete box culvert.

King County is replacing the bridge because it is load-restricted and unable to support certain types of large trucks including some types of fire engines used by adjacent fire districts, full-size garbage trucks, dump trucks and concrete mixers, according to the county. The replacement culvert will provide unrestricted access for all vehicles. It will also provide environmental enhancements by improving fish passage and removing creosote timber pilings from Mullen Slough.

The street at the bridge location has a traffic volume of about 23,000 vehicles per day, of which 2,600 vehicles are trucks carrying an estimated 4 to 10 million tons of freight per year. This road is a designated county snow/ice route, lifeline route and Green River Valley flood evacuation route.

The estimated cost of the project is $2.9 million, funded through the King County Capital Improvement Program.