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

A map showing new ramps and roundabouts for the southbound I-5, SR 18 and SR 161 Triangle area.

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.
  • Add a left turn only lane at 20th Avenue South and SR 161, improving the intersection to work better with the new roundabout.