What is the I-65/I-70 North Split Project (North Split Project)?
The North Split Project is an upgrade of the existing interchange where I-65 and I-70 meet on the northeast side of downtown Indianapolis. The North Split is the second-most heavily traveled interchange in Indiana. Pavement and bridges in the interchange area require rehabilitation or replacement due to their poor structural condition. The North Split Project will also provide the opportunity to improve safety and operations for all users.
INDOT recently released the North Split Alternatives Screening Report, which analyzes a range of preliminary alternatives and identifies the preliminary preferred alternative to be evaluated in greater detail in the Environmental Assessment (EA). The EA is being developed to meet the requirements of the National Environmental Policy Act of 1969 (NEPA). The NEPA process for this project began by identifying project needs and scoping potential alternatives to be evaluated in the environmental study, and will continue with public involvement and further analysis into 2019 and 2020.
Why is this happening now?
About 214,000 vehicles use the North Split interchange each day. Portions of the North Split interchange were built 50 years ago and the infrastructure is in poor condition. It is operating at full capacity and crash rates are higher than statewide averages for urban interstates. Traffic regularly slows or stops during peak travel periods. The interchange is at the end of its useful life. Specifically:
- Due to poor structural condition, 11 bridges need rehabilitation or replacement during the next 5 years. Another 16 bridges require rehabilitation or replacement in the next 10 years
- Deteriorating pavement requires constant repair and patching on the roadway and shoulders, which is expensive and disruptive for users
- The crash rate is almost twice as high as other urban interstates. Injury rates are almost three times as high
- The configuration of the existing interchange creates “weaving” conflicts as motorists cross paths to reach their destination. Weaving movements with high volumes of traffic are the primary cause of crashes and congestion in the North Split
What is the purpose of the North Split Project?
The purpose of the North Split Project is to rehabilitate ad improve the existing interstate facilities within the project area and reduce or eliminate conditions that contribute to high crash rates and congested conditions.
What needs must the project meet?
The North Split Project must meet the following transportation needs:
- Correct deteriorated bridge conditions
- Correct deteriorated pavement conditions
- Improve safety by eliminating conflict points and realigning curves
- Improve interchange operations and reduce congestion by eliminating bottlenecks
How will the project benefit drivers who use the interchange?
Improvements to the interchange will result in safer conditions for those who use the interchange. Traffic will flow more smoothly due to the elimination of existing conflict points and bottlenecks. Replacing the pavement and bridges will result in fewer short-term delays due to roadway repair and maintenance projects.
What project activities are currently underway?
INDOT recently published the Alternatives Screening Report that defines and analyzes the different alternatives for the North Split and identifies a preliminary preferred alternative to be advanced in the EA, subject to public comment.
The public can review and provide input on the analysis in the report and the preliminary preferred alternative.
ALTERNATIVES SCREENING REPORT FAQS
What is the purpose of Alternatives Screening Report?
The purpose of the Alternatives Screening Report is to evaluate preliminary alternatives for the North Split project and to identify the preliminary preferred alternative to be analyzed in greater detail in the EA, subject to public and agency input received during the comment period for the Screening Report.
How were preliminary alternatives developed for the Alternatives Screening Report?
An inventory of existing conditions was conducted, safety and operational problems were defined, and constraints were identified based on environmental resources and public input. Potential solutions were developed to address the safety and operational problems while minimizing the impacts to adjacent properties. Options were developed to represent trade-offs between traffic service and impact to adjacent properties. Addressing safety problems was a priority in all preliminary alternatives.
Were final designs developed for the preliminary alternatives?
Final designs were not developed for the Alternatives Screening Report. Layouts were conceptual and subject to adjustment based on more detailed engineering. In most cases, preliminary alignments, pavement edges, side slopes and retaining walls, and bridge sizes were defined to meet current standards in the Indiana Design Manual used by INDOT. Some minor variations requiring “design exceptions” from FHWA were identified. Graphic layouts were prepared for each preliminary alternative.
What alternatives were studied in the Alternative Screening Report?
Five alternatives were evaluated in the Screening Report:
- No-Build – The existing interchange would stay as it is, without replacement of pavement and bridges, and with no safety or operational improvements. A No-Build Alternative must be included as a project alternative in accordance with NEPA
- Transportation System Management (TSM) – Policies, strategies, and technologies would be used to improve freeway performance or to divert traffic away from the project area
- Bridge and Pavement Replacement In-Kind – Bridges and pavement would be rehabilitated or replaced at their current locations, bringing them to current design standards where feasible, without changing the alignment and grade of roadways within the interchange
- Efficient Interchange Reconstruction – This alternative includes three options that realign highway sections and ramps to provide safer and more direct connections through the interchange. Bridges and pavement would be replaced, but there would be no added through lanes. Existing movements would be removed in some options to minimize impacts
- Full Interchange Reconstruction – Highways and ramps would be realigned to improve safety and operations. Bridges and pavement would be replaced, and all existing movements would be accommodated. Added through lanes would provide a good level of service in the future
Review the Alternatives Screening Report to learn more about each alternative.
How were the preliminary alternatives evaluated?
Once the preliminary alternatives were identified, a three-step screening process was used for evaluation, as described below:
- Purpose and Need. Each preliminary alternative was evaluated to determine whether it would meet the purpose and need of the project. Alternatives not meeting the purpose and need were not carried forward in the screening process
- Access Options and Community Impacts. Alternatives meeting the project purpose and need were defined in sufficient detail to identify potential impacts. Options were identified to reduce these impacts by modifying entrance and exit ramps, with a primary focus on increasing safety in the interchange, to provide a range of access options and community impact levels to represent potential trade-offs
- Review of Trade-offs. Trade-offs between access options and community impacts are identified and reviewed in the Alternatives Screening Report. Based on this information, INDOT proposes a preliminary preferred alternative that appears to optimize this balance, while correcting physical deficiencies and addressing the greatest safety needs in the interchange
What are the greatest safety needs in the interchange?
Crash data was reviewed at tenth-mile intervals through the interchange for the period 2012 to 2016 to identify the most hazardous locations in the interchange. Four locations were identified as having particularly high crash rates, as described below:
- Meridian/Pennsylvania Street Exit Ramp. This is the highest crash location in the interchange area. Northbound traffic on I-65 must cross I-70 traffic from the east to access this ramp. Locations where traffic must cross to make certain movements are called weaving areas
- Meridian/Delaware Street Entrance Ramp. This is the second highest crash location in the interchange. Traffic entering at this ramp and wishing to access eastbound I-70 must cross all southbound I-65 traffic, creating another weaving area
- I-65/I-70 Merge Point. I-65 and I-70 both have two lanes as they pass through the north split approaching the south leg of the interchange. The two I-70 lanes must merge to one lane just before joining with I-65 to create a three-lane combined roadway of I-65/I-70. This merge area is the third highest crash location in the interchange
- Eastbound I-70 Curve. The location where I-70 turns eastward to leave the North Split on the east leg is the fourth highest crash location in the interchange. Three lanes of traffic approach this abrupt curve on an uphill grade.
Alternatives must improve conditions at the first two high crash locations and should improve conditions at the second two locations to meet the project purpose and need
Which alternatives were eliminated based on purpose and need?
Alternative 1 (No-Build) and Alternative 2 (TSM) were eliminated because they would not meet the need to correct deteriorated bridge and pavement conditions in the project area. The No-Build Alternative would be carried forward as a baseline for evaluating other alternatives. Alternative 3 (Bridge and Pavement Replacement In-Kind) was eliminated because it would not meet the project needs to improve safety and operations in the interchange.
Alternatives 4 and 5 would meet the purpose and need by replacing deteriorated infrastructure, improving traffic safety, and providing an acceptable level of service. They differ in their physical footprint, need for retaining walls, and the mobility they provide for motorists.
What are the trade-offs of mobility and impact with Alternatives 4 and 5?
Trade-offs between the three options of Alternative 4 and Alternative 5 occur on the west leg of the interchange. The west leg has the most severe safety problems due to the weaving conditions created by the ramps in each direction. Weaving is a term for traffic forced to cross paths to reach a destination, such as traffic entering from Delaware Street that must cross I-65 traffic to reach eastbound I-70. The weaves must be eliminated in order to meet the project purpose and need with respect to safety.
The weaves are eliminated in different ways in each alternative, as described below:
- Alternative 4a – Close the existing Pennsylvania Street exit ramp and Delaware Street entrance ramp. This alternative would have the smallest footprint, with minimal pavement widening and no outside retaining walls, but current access and egress would be lost on the west leg.
- Alternative 4b – Reconfigure the interchange to separate the movements that currently cross paths in the weave areas. New bridges would be added in the interchange area and a two-lane ramp would be added on the north and a one-lane ramp on the south. The additional pavement width would require retaining walls up to about 18 feet high on the north side of I-65 and about 33 feet high on the south side of I-65, but all existing movements would be accommodated.
- Alternative 4c – Reconfigure the interchange and the west leg to separate the movements that currently cross paths and eliminate some movements that currently exist. Single lane ramps would be added on each side of the I-65 mainline, with retaining walls up to about 11 feet high on the north side of I-65 and up to about 7 feet high on the south side of I-65. Westbound I-70 traffic would lose access to the Pennsylvania Street exit, and southbound I-65 traffic would lose access to the Ohio Street and Michigan Street exits. Traffic entering from the Delaware Street ramp would lose immediate access to southbound I-65, but could use the collector-distributor roadway that currently accesses Ohio and Michigan Streets to access I-65 further south. All other existing movements would be accommodated.
- Alternative 5 – Reconfigure the interchange and the west leg to separate the movements that currently cross paths in the weave areas, and provide two-lane ramps on both sides of the I-65 mainline. Provide added through lanes to improve traffic service. Alternative 5 would require retaining walls up to about 30 feet high on the north side of I-65 and up to about 37 feet high on the south side of I-65.
What is the Preliminary Preferred Alternative and why was it chosen?
It is INDOT’s determination that among the alternatives that meet the project purpose and need, Alternative 4c would provide the best balance of meeting safety and mobility needs while minimizing or potentially eliminating the need for retaining walls along the legs of the interchange, and Alternative 4c does not include added through lanes on the interstates. Subject to input from agencies, advisory committees, and the public during the comment period of the screening report, Alternative 4c will be the preferred alternative to be analyzed in detail in the EA.
When will a final North Split alternative be selected?
A preliminary preferred alternative (Alternative 4c) is identified in the Alternatives Screening Report. A final alternative will be selected and published in the EA in early 2020.
A coalition of interests has commissioned an independent economic study of downtown interstates. Why didn’t INDOT wait for the results of this economic study before releasing the Alternative Screening Report?
The studies are independent of each other. Based on information provided to INDOT, the economic study is considering the full downtown interstate system. The screening report is evaluating alternatives at the North Split interchange. Ultimately, each study may inform the other with respect to long range planning, but this will not depend on which study is released first. Studies of the North Split have reached an important milestone and the public will benefit from having this information without delay.