The I-205 and Mill Plain Boulevard interchange is the busiest in Clark County. More than 100,000 vehicles travel through that area daily. It’s a very congested interchange since there isn’t an on or off ramp for three miles between Mill Plain and SR 500. Now there is! The new I-205 interchange at 18th Street opened Wednesday, July 20.
You can now use the new I-205 northbound off-ramp to 18th Street and the new I-205 southbound on-ramp from 18th Street. WSDOT also built a roundabout at the intersection leading to the I-205 southbound on-ramp, that way you won’t have to wait through a light to get onto the highway.
The opening of this new interchange comes about a month after WSDOT opened a new I-205 southbound off-ramp to Mill Plain Boulevard. The longer separated off-ramp takes traffic off I-205 sooner and reduces backups. A new I-205 northbound on-ramp from Mill Plain is also an extended ramp that gives you more distance to merge onto the interstate.