I-205 Strategic Corridor Study

Preliminary Alternative Packages

The consultant team has developed five alternative improvement packages to address the 2020 baseline operational deficiencies in the I-205 Strategic Corridor Study Area. The alternatives range from local street system improvements, with no freeway access modifications to significant interchange modifications and new interchange scenarios.

The following summary presents the key features of each of the alternatives. These were presented at the June 22 Citizens' Advisory Committee meeting and will be reviewed in more detail at the upcoming August 24th Citizens' Advisory Committee meeting.

Alternative A: Regional Arterial Access and Capacity Improvements

• Widen East-West arterials to provide improved alternatives to Mill Plain Road between NE 112th Ave and NE 164th Corridor.
• Improve North-South access to provide alternatives to I-205 between Mill Plain Road and SR 500.
• Provide various local intersection improvements to mitigate identified 2020 baseline operational deficiencies. 

Alternative B: New NE 18th Street/NE Burton Road Split Diamond Interchange

• Construct a split diamond interchange between NE 18th Street and NE Burton Road (consistent with recommendation of 1996 I-205 and East-West Arterials Study Final Report).

Alternative C: New NE 18th Street Interchange (Single Point Urban Interchange or Traditional Diamond Interchange)

• Construct a new interchange at NE 18th Street (either single point urban interchange (SPUI) or traditional diamond urban interchange).

Alternative D: Local Access Improvements to SE Mill Plain Road

• Reroute traffic between McGillivray Boulevard and SE Mill Plain Road from Chkalov Drive to SE 117th Avenue.
• Construct connection from north leg of SE Mill Plain Road/SE 117th Avenue intersection to 112th Avenue.
• Extend SE 5th Street to connect SE 117th Avenue to Chkalov Drive.
• Remove left turn from west bound Mill Plain Road to north bound Chkalov Drive.
• Remove traffic signals at Chkalov Drive/Mill Plain Road and Fred Meyer entrance, and add signals to SE 5th Street at Chkalov Drive and SE 117th Avenue intersections.

Alternative E: Modified I-205/Mill Plain Road Interchange

Alternative E presents several scenarios for improvements in the Mill Plain Road/I-205 interchange area to address operational issues. Option "elements" involve modifications to the south ("S1" and "S2") and north ("N1" and "N2") of Mill Plain Road. These specific options involve the following features:

S1 - Add a direct ramp connection from I-205 northbound to SE McGillivray Boulevard.

S2 - Add a direct ramp connection from I-205 northbound to SE Chkalov Drive south of the existing Fred Meyer access intersection. The ramp would also connect to an east-west collector road along SE 5th Street alignment (providing direct connection to Mill Plain Road via SE 5th Street/SE 131st Avenue).

N1 - Add direct ramp connection to NE 112th Avenue north of Mill Plain Road and add a collector-distributor road east of I-205 between SR 14 and SE 9th Street.

N2 - Add direct ramp connections (half-diamond interchange) to and from the south at NE 18th Street to accommodate northbound off and southbound on traffic on I-205.

Potential combinations of these options are presented in the table below. 

	S1	S2	N1	N2
Alternative E1	X		X
Alternative E2	X			X
Alternative E3		X	X
Alternative E4		X		X