GARRITY BLVD/IDAHO CENTER BLVD INTERCHANGE PROJECT
PROVIDING BETTER FREEWAY ACCESS
The purpose of this project is to reconstruct the interchange by replacing the existing overpass and access ramps to I-84. The new interchange "Exit 38" will provide congestion relief dy incorporating a new design. One design option being considered is the Single Point Urban Interchange, or SPUI. If constructed it will allow all traffic to meet at one signal reducing delays and allowing for better traffic storage. this is one of two currently planned SPUI interchanges, The other at Vista Ave. The new interchange will also get rid of the current lane separations underneath the bridge. The new interchange is part of the planned widening of interstate 84 from Meridian to the Garrity interchange.
PROJECT STATS
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Basic Information:
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Roadgeek Vision for this project:
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PROJECT BACKGROUND
Currently the interchange at Garrity/Idaho Center is not properly designed. Originally this interchange was 3 lanes wide. one lane each way and a left turn lane for traffic entering the freeway. Due to major congestion the interchange was widened to 5 lanes by excavating the area behind each of the pillar on either side of the underpass and installing retaining walls. This created space for an additional lane in each direction. This split lane configuration caused by this design was a temporary fix. There are some safety concerns because traffic heading in the same direction under the overpass is split by the bridge pillars. Additionally, with the increased traffic demands there is no way to expand the existing interchange.
The new interchange will also provide a new avenue for growth in the coming years. With new developements recently constructed and new ones planned demand is expected to increase. Additionally the entertainment venue at the Idaho Center creates large volumes of traffic that must be addressed, especially since the venue will likely see increased usage over the years, and the Western Idaho Fair may consider relocation here as well.
WHAT WILL IT DO TO HELP
Once completed the new interchange will allow traffic to flow more smoothly. and will allow for more expansion in the future. This project will significantly increase safety for motorists with upgraded ramps, new interchange configuration and no more split lane configuration. This project is expected to be built in conjunction with the multi-million dollar widening of I-84 between Meridian and Nampa.
INTERCHANGE CONFIGURATIONS
Expected interchange configurations include a reconstructed diamond interchange or a new Single Point Urban Interchange (SPUI) design which is the recommended design.
VISION FOR GARRITY BLVD & IDAHO CENTER BLVD
The new interchange paves the way for some key improvements. One of those is the widening of Interstate 84 whith is currently congested and the scene of numerous traffic incidents. it also provides better access to the freeway. This project has been identified as one of key importance for addressing continued growth for the region.
RECOMMENDATIONS
The new interchange should be constructed as a single point urban interchange (SPUI). This design is best because it only needs one traffic control point with 3 phased operations. This will reduce wait times. provide more traffic storage and allow traffic to more easily negotiate left turns through the intersection. It allow more traffic to pass through the interchange during a signal cycle than a traditional diamond design with increased safety.
The interchange design will be more costly because of the wider and longer overpasses needed to make room for the intersection underneath. Impacts on right of way should be minimal since the interchange can be constructed completely with in the current right of way, and no existing structures will be impacted as well.
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Updated 05/28/2008