I-5 - SB CD Lane and 356th St. Intersection Improvements - Project map

a large map of the project area in Federal Way where WSDOT proposes to redesign the southbound I-5 ramps to SR 18, build a roundabout on S. 356th Street and build a new southbound I-5 exit ramp to S. 356th Street and SR 161.
Improvements to the I-5/SR 18/SR 161 interchange area would include the following:



  • Redesigning the southbound I-5 exit to SR 18 to accommodate traffic turning both eastbound and westbound on SR 18. The existing loop ramp to eastbound SR 18 would be demolished.
  • A new southbound I-5 exit to South 356th Street and SR 161. One leg of the exit will drop directly onto South 356th Street. The second leg of the exit will go to SR 161.
  • A new two-lane roundabout on South 356th Street at the SR 161 and 16th Avenue South intersections.