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Glenn Muldoon DDI
SPREE
Project Summary
February 24-25, 2015
Project Purpose & Need
Purpose:
• To improve operations, capacity, and safety for interchange traffic (vehicles, freight movements, non-motorized, etc.)
An improved interchange is needed because:
• Ramp intersections are congested and queues exceed available storage
• Not enough through lanes on Muldoon Road bridge
• Pedestrian facilities are circuitous and 1/3 of the pedestrians do not use them
• Existing bridge clearance over the Glenn Highway is below the minimum standard (<16’)
Interchange Background/History
Glenn Highway: 22,400 vehicles/day
Muldoon Road: 14,300 vehicles/day
Glenn Highway: 52,660 vehicles/day
Muldoon Road: 29,968 vehicles/day
1974 2012
2007 vs. 2012 Traffic Volumes
Existing Traffic Conditions
• Interchange is congested in the morning and evening peak hours
• Queues in the morning and evening peak hours and on weekends extend beyond the available storage – particularly for the eastbound off-ramp from Glenn Highway
• Queues from left-
turning movements on
bridge exceed the
available storage and
obstruct the single
through lanes in both
directions
North-South Pedestrian Access
Work Completed To Date
• Public and Agency Outreach
• Preliminary Engineering
• Preferred Alternative selected
• Environmental document in
progress
• Survey & mapping
• Geotechnical investigations in
progress
• Plans-In-Hand under review
Diverging Diamond
• Complete interchange
reconstruction
• Constructs two new three-lane
bridges
• Removes opposing traffic for left-
turning and right-turning
movements to/from the ramps
• New pedestrian facilities
accessible from both sides, new
undercrossing
• Shoulders wide enough to be
retrofitted as a bike lane
Diverging Diamond Interchanges
• Also known as a double crossover diamond
• 34+/- built in the U.S. to date
• Allows free-turning left and right turns
• More efficient two-phase signals
Why a DDI?
• More efficient and longer life span than other
alternatives
• Safety performance of other DDI’s suggests
significant improvements over other types of
interchanges
• Least disruption to traffic during construction
• No need to build temporary structures -- ~$9
million less than other alternatives
Bridge Typical Section
• Wider lane widths to accommodate oversized vehicles
– Shoulder use for off-tracking
• Paving widths align with pavement markings
Glenn Highway Typical Section
• Two, two-span bridges that include 3 through lanes and
a future HOV lane
• Removal of loop ramp lanes
Project Challenges
• Aggressive schedule – 9 months from Local
Review to bid ready plans
• 36” water main routes under the south abutment of
the existing bridge and may require relocation
• Controlled access modifications on three corners
• Project initiated with State funds – following federal
process to qualify for federal funding
• High profile, gateway interchange with strong multi-
modal desires from the community
• High traffic volumes and limited detour options
Construction Phasing—Diverging Diamond
• Maintains use of existing
Muldoon Road overpass
while new bridges are
constructed
Public Education
• Vissim model and Civil3D DTM used to create
an animation to share with the public
• Website will be used to share the video, driving
tips, links to other DDI projects, etc.
• Video is still in production, but we have an
advance sample for viewing
Cost Estimate
Design Engineering $3,600,000
Right-of-way $300,000
Utility Relocation $1,400,000
Construction $33,900,000
CE & ICAP $7,000,000
Total $46,200,000
Project Schedule
Project Start May 2013
Public and Agency Outreach Fall 2013 – Spring 2015
Preliminary Engineering Summer – Fall 2013
Preferred Alternative selected November 2013
Environmental documentation Spring 2014 - Spring 2015
Final Design Feb – Aug 2015
Bidding Fall 2015
Construction 2016-17
Project Information
• Visit: www.glennmuldoon.com
• Email: [email protected]
• Facebook:
Glenn Highway and Muldoon
Road Interchange
Improvements
Questions & Comments
