NEPA Process
The EIS process is expected to take two years to formally document project approvals.
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The Federal Highway Administration (FHWA) will be the Federal lead agency overseeing and ultimately responsible for the EIS process. ITD is the project sponsor providing day to day management.
Additionally, the US Army Corps of Engineers (USACE) and the Federal Aviation Administration (FAA) have agreed to be Cooperating Agencies which means they will participate in the process and plan to review and adopt FHWA’s EIS and Record of Decision.
A Preferred Alternative will be selected based on:
- Public input from this meeting and previous meetings conducted as part of the PEL process
- Forecast travel demand traffic analysis
- Refined analysis of the design and constructability
- Findings from more detailed environmental analysis including impacts to:
- Community resources
- Sensitive noise receptors
- Wetlands, parks and recreational resources
- Historic properties
- Input from the City of Idaho Falls, Bonneville County, the Bonneville Metropolitan Planning Organization, the Idaho Falls Regional Airport and other state and federal resource agencies
* The Federal Highway Administration (FHWA) will be the Federal lead agency overseeing and ultimately responsible for the EIS process. ITD is the project sponsor providing day to day management.
Additionally, the US Army Corps of Engineers (USACE) and the Federal Aviation Administration (FAA) have agreed to be Cooperating Agencies which means they will participate in the process and plan to review and adopt FHWA’s EIS and Record of Decision.
No-Build Alternative
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Features
- Assumes the 2045 travel demand forecast volumes travel on the existing transportation network with no changes to the I-15 or US-20 access or interchange configurations
- Includes locally programmed improvement projects that are expected to be completed whether the I-15/US-20 Connector project is completed or not
Benefits
- The interstate and highway facilities remain the same without impacts to businesses or homes
Challenges
- Congestion will continue to increase as the travel demand on both I-15 and US-20 grows. Congestion can lead to increased air pollution and travel times as well as safety issues like rear-end crashes.
Alternative E3
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Features
- Relocate the existing I-15/US-20 interchange from Exit 119 at Grandview Drive to a new interchange near Olympia Street and realign a portion of US-20
- New bridges would carry traffic from I-15 to US-20 over Lindsay Boulevard, the Pioneer Canal, the Snake River, and Fremont Avenue before connecting with existing US-20
- A reconfigured interchange at the US-20 Exit 309 at Science Center Drive would improve access to local streets
- Multimodal improvements would include new bike lanes and shared-use paths, and new or improved sidewalks
Benefits
- Improves safety and operations by increasing the distance between I-15 interchange
- Provides more direct access from I-15 to the Idaho Falls Airport via the new 1-15 Interchange
Challenges
- Impacts to grain silos, an RV park, and other local businesses east of I-15
- Relocation of the businesses served by the railroad
- Construction activities will impact existing businesses and motorists
UPDATE: Alternative E3
Updates
- Exit 119 cross street over I-15 was realigned to the south on the west side of I-15 to stay out of airport runway protection zone
- Due to the I-15 widening project between Pocatello and Idaho Falls, ITD is allowing for a future third lane in each direction on I-15 with this alternative so that it is consistent through the corridor
Alternative H2
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Split-Diamond Interchange
The split-diamond interchange is a potential option to address the existing conditions. More analysis will need to be performed during the NEPA process to evaluate options on I-15 between Exits 118 and 119.
Features
- The existing I-15/US-20 interchange would be relocated from Exit 119 at Grandview Drive to a new interchange on I-15 just north of the airport
- US-20 would be on a new alignment from the new I-15 interchange east until connecting with the existing US-20 at a new interchange near E 49th N
- A new interchange would be constructed on the new alignment at N 5th W
- I-15 Exits 118 and 119 would be reconfigured to eliminate existing weaving conflicts
- Multimodal improvements would include new bike lanes and shared-use paths, and new or improved sidewalks
Benefits
- Improves traffic operations of the existing I-15 interchanges by separating regional through traffic and local traffic
- A split-diamond interchange would remove weaving and backup on I-15
- Allows for construction in phases to minimize impacts to motorists
Challenges
- Alignment goes through a construction material landfill
- Creates a new northern alignment for US-20 through an undeveloped area
UPDATE: Alternative H2
Updates
- The mainline improvements near the airport have moved north slightly to reduce impacts to airport properties
- The new interchange between I-15 and US 20 is being designed to not preclude
a future connection to the west.
Ultimate Alt H2 Video Ultimate Alt H2 Virtual Tour - The alignment of US 20 through the Hatch Pit has been refined based on a geotechnical analysis to optimize constructability
- Due to the I-15 widening project between Pocatello and Idaho Falls, ITD is allowing for a future third lane in each direction on I-15 with this alternative so that it is consistent throughout the corridor
Schedule
