quad-roundabout double-diamond interchange
DESCRIPTION
Quad-Roundabout Double-Diamond Interchange. ITS World Congress 2011 Joel K. Marcuson, PE Ulteig Engineering Fargo, ND, USA. Background. Concept Developed for Design/Build I-494/TH 169 Project Minneapolis, MN, USA . 3 Traffic Signals Create 3mile Backup Every Morning on TH 169 - PowerPoint PPT PresentationTRANSCRIPT
Quad-RoundaboutDouble-Diamond Interchange
ITS World Congress 2011Joel K. Marcuson, PEUlteig EngineeringFargo, ND, USA
Background
Concept Developed for Design/Build I-494/TH 169 ProjectMinneapolis, MN, USA
3 Traffic Signals Create 3mile Backup Every Morning on TH 169Only Signals on TH 169 Corridor
Project Need
Remove 3 Signals and Old-Fashioned Cloverleaf/Signalized Intersection Design
Replace with Direct Interchange,Bridges/Roundabouts – Local Traffic6 Roundabouts = MOT Opportunity
Project Description
Keep Through Traffic on I-494 and TH169 MovingMaintain Access to Local Traffic Around and Through Project
MOT Objective
Remove Signals QuicklyBuild Bridges Quickly
Run Turning/Local Traffic on Roundabout System
MOT Approach
Existing Conditions - Current
Proposed Plan - Ultimate
MOT Plan – Full Access (Interim)
Using Permanent Features (Roundabouts) for New PurposeAccommodates all Traffic and Movements
Innovation
Innovation Description
Full Access, Improved Traffic EarlyTH 169 Free Flow
I-494 Bottleneck RemovedAvg Speeds Doubled
Unconstrained Flow – During Construction
Benefits of Innovation
Table 1 - Level of Service*, Average Speeds
Stage ExistingAM/PM 1A AM/PM 1B AM/PM 1C AM/PM 2 AM/PM
Avg Speeds(mph) 13/11 15/10 12/8 14/8 27/27
N TH 169 LOS B/C B/C C/C C/C Free**
S TH 169 LOS A/D D/C A/B C/B Free**
Highwood LOS E/F F/F E/F E/F Free**
Benefits of Innovation
Current Need - > Service< System Interchange
Quad-Roundabout DD Interchange Fills That Need
Results of Innovation
Flooding – Closed All Nearby Crossings Except TH 169Volumes Increased on TH 169Restripe 169, Remove Signals
Nature Interfered
$5B DeficitGovernment Shutdown
Contractor Stopped
Politics Interfered
Contractor Lost Time, TwiceLost Money, Twice
New Approach – Build Final QuicklyQuad Roundabout DD Abandoned
Result
One of Best Designs Never ImplementedAn Approach That Will Work
For Right Occasion/ Right Time
Quad-Roundabout DD Interchange
Are EverythingStill Want to Share Idea
Could be Groundbreaking
Timing/Circumstances
Between Service and SystemHigh-Performance Service Interchange
Significant Cost SavingsSignficant Benefits
New Category Needed
System Costs = $250-500MHigh-Performance = $25-50MSimilar Results, 10% of Cost
$$ Impacts Important
Couldn’t Make it “Not” WorkDoubled Traffic – No Appreciable
Change in Performance
What We Discovered
Questions?