Appendix D Traffic Impact Analysis - westplainseis.com

7.1.3 2032 With Project (Alternatives 1, 2 & 3) Mitigations and Descriptions
Listed below are improvements recommended for consideration to reduce traffic impacts associated with
the subject project. The project’s recommended proportional share contribution for each mitigation is
also listed. The proportional share for off-site intersections is calculated by divided the project generated
traffic volume by the total intersection volume for each respective scenario.
2032 Alternative 1 Mitigations:
Hwy 2 / Craig: Install traffic signal and widen/improve intersection approaches to include dual
EB, NB and SB left turn lanes and a 2 nd NB thru lane. Alternatively, consider installation of a
roundabout.
Project Proportional Share: 30.0%
Resulting LOS & Delay (sec): F/101.5 / F/94.9
Hwy 2 / Lundstrom: Restripe and widen approaches to accommodate exclusive NB and SB right
turn lanes. Alternatively, 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): F/ n/a / E/42.3 (alternative – turn restriction)
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: Optimize signal timing. Alternatively, modify signal timing and add 3 rd EB
and WB auxiliary through lanes.
Project Proportional Share: 20.4%
Resulting LOS & Delay (sec): F/131.5 / C/25.0 (alternative)
Hwy 2 / Hayford: Optimize signal timing and consider converting the inside SB thru lane to a
2 nd SB left turn lane. Widen the EB and NB approaches for exclusive right turn lanes. Restripe
the wide paved median for a 2 nd WB left turn lane. Add 2 nd NB left turn lane. Add a 3 rd WB thru
lane on the approach and downstream of the intersection as an auxiliary thru lane.
Project Proportional Share: 15.3%
Resulting LOS & Delay (sec): F/95.4
Craig / SR 902: Install traffic signal or consider installation of a roundabout.
Project Proportional Share: 27.0%
Resulting LOS & Delay (sec): C/20.7 / B/16.1 (roundabout)
Hwy 2 / Fairchild AFB: Modify signal timing. Add NB left turn lane and WB thru lane.
Project Proportional Share: 11.6%
Resulting LOS & Delay (sec): D/50.5
Craig / Sixth Ave.: Widen the intersection approach to provide and exclusive NB right turn lane
or consider installation of a roundabout.
Project Proportional Share: 33.5%
Resulting LOS & Delay (sec): E/47.3 / C/20.5 (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): D/51.0 / F/110 (roundabout)
Craig / North Driveway.: Consider adding a 2 nd NB thru lane. If this improvement is chosen it
is recommended that the 2 nd NB thru lane be continuous from Highway 2 to 6 th Ave.
Alternatively, consider installation of a roundabout which would also achieve a satisfactory level
of service.
Project Proportional Share: 100%
Resulting LOS & Delay (sec): E/37.3 / B/11.4
West Plains Development – Spokane Tribe Page | 84
Traffic Impact Analysis April 28, 2011