Appendix D Traffic Impact Analysis - westplainseis.com

Hwy 2 / Hayford: Optimize signal timing and convert the inside SB thru lane to a 2 nd SB left
turn lane.
Project Proportional Share: 15.8%
Resulting LOS & Delay (sec): D/45.9
Craig / SR 902: Install traffic signal or consider installation of a roundabout.
Project Proportional Share: 23.7%
Resulting LOS & Delay (sec): B/15.6 / A/8.6 (roundabout)
Hwy 2 / Middle Driveway: Install traffic signal and approach improvements (SB Middle
Driveway); install a WB right turn lane. Alternatively, consider installation of a roundabout.
Project Proportional Share: 100%
Resulting LOS & Delay (sec): C/31.1 / A/9.8 (roundabout)
Alternative 3
Recommend improvements are summarized below along with the estimated proportional fair share
contribution.
Hwy 2 / Craig: Install traffic signal and widen the NB and SB approaches to provide and
exclusive left turn lane. Alternatively, consider installation of a roundabout.
Project Proportional Share: 30.2%
Resulting LOS & Delay (sec): C/28.2 / A/7.1 (roundabout)
Hwy 2 / Hayford: Optimize signal timing and convert the inside SB thru lane to a 2 nd SB left
turn lane.
Project Proportional Share: 13.6%
Resulting LOS & Delay (sec): D/40.6
Craig / SR 902: Install traffic signal; alternatively, consider installation of a roundabout
Project Proportional Share: 20.6%
Resulting LOS & Delay (sec): B/15.1 / A/8.2
Hwy 2 / Middle Driveway: Install traffic signal and approach improvements (SB Middle
Driveway); install a WB right turn lane. Alternatively, consider installation of a roundabout.
Project Proportional Share: 100%
Resulting LOS & Delay (sec): C/29.3 / A/9.2 (roundabout)
2032 Cumulative Mitigation Improvements
The improvements identified below in addition to the improvements identified above are required to
mitigate 2032 Cumulative With Project conditions.
2032 Alternative 1 Mitigations (in addition to Alt. 1 Ph. 3 2019 mitigations above):
Hwy 2 / Lundstrom: Consider restriction of NB and SB left turn movements and installation of
EB/WB right turn lanes.
Project Proportional Share: 25.5%
Resulting LOS & Delay (sec): E/42.3
Hwy 2 / Lawson: Modify the signal timing. Modify and widen NB and SB approaches as
necessary to provide dedicated left turn lanes.
Project Proportional Share: 25.1%
Resulting LOS & Delay (sec): D/40.6
Hwy 2 / Garfield: Add 3 rd EB and WB auxiliary through lanes.
Project Proportional Share: 20.4%
Resulting LOS & Delay (sec): C/25.0
Hwy 2 / Fairchild AFB: Modify signal timing. Add NB left turn lane and WB thru lane.
Project Proportional Share: 11.6%
West Plains Development – Spokane Tribe Page | 91
Traffic Impact Analysis April 28, 2011