Project Description

The Big Walnut Interchange is a planned freeway interchange on Interstate 71 at mile marker 124, at or near Big Walnut Road in Orange Township, Delaware County, Ohio near Alum Creek State Park.

Purpose and Need

The primary purpose of this project is to improve regional access for southern Delaware County by creating system linkage in the regional network and by removing regional traffic from congested local routes. System linkage between the existing primary north/south regional corridor and a new east/west regional corridor will support travel patterns for up to 90% of the county population. Removing congested local roadways from the regional access network will also support those travel patterns.

A secondary purpose of this action is to improve access to Alum Creek State Park for visitors from outside the region. The largest attractions within the State Park do not have direct access to the regional access corridors. Improving access will assist with wayfinding for visitors to the region and will reduce the travel time of large recreational vehicles on the local county roadway network.

What Has Been Done So Far

In 2015, Delaware County commissioned a Feasibility Study to update previous work that had been done in 2006-09 for this project. Between 2015 and 2020, Delaware County and ODOT identified 3 feasible locations for interchange ramp intersections on Africa Road (2 locations) and on Big Walnut (1 location) that would meet the project’s purpose and need.

Impacts of each of the 3 “build” (with interchange) alternatives has been compared to the “no-build” (without interchange) scenario.  This is a long and intensive process requiring analysis of the Central Ohio regional traffic model, and micro-level simulation of area intersections in multiple configurations.  In addition, critical environmental resources have been identified, such as wetlands, water bodies, existing homes and endangered species habitats.

What is the Current Status of Project

In January 2018, the ODOT Transportation Review Advisory Council (TRAC) approved Tier II status for the project, which means that the project is authorized for continued development through preliminary engineering and detailed design.  The TRAC has maintained the project on its Tier II list since 2018.

In November 2022, Delaware County resumed the study of this interchange, focusing solely on updating the previous traffic analysis to determine if the interchange is technically feasible from a traffic management standpoint.  This work will continue through the summer of 2023.

This study does not yet include a full feasibility study evaluation and is limited to a technical evaluation of the interchange traffic flow.  Delaware County and ODOT will evaluate if any further project development will occur after the traffic study update is completed.

What Remains to be Done

If the traffic study update indicates that the project is technically feasible and can meet required traffic criteria set by ODOT and the Federal Highway Administration, ODOT and Delaware County will consider moving ahead with further study of the interchange and expand the analysis to include things like safety, traffic, noise, and environmental impacts.

Previous analysis of the ramp location alternatives would need to be updated and fully vetted in terms of conformance with required engineering and environmental requirements.  General public comment would be sought on all alternatives through formal meetings and comment opportunities which would be advertised to the public.

If, and only if, one of the Build alternatives is determined to be superior to others in terms of its benefits to the public, has a cost that can be funded through current and projected revenues, and has public support within the context of the purpose and need of the project would it be selected as the Preferred Alternative and advanced for further development.

If the No Build alternative is selected as Preferred, further development of the project will be suspended or the Purpose and Need of the project will be reevaluated.

If a Build alternative is selected as Preferred, Delaware County would work with ODOT to prepare and submit an Interchange Justification Study (IJS) to the Federal Highway Administration (FHWA) for review.

If FHWA approves an IJS, Delaware County and ODOT would continue developing the project through environmental and final engineering stages.

Currently, DCEO has no definitive schedule for construction of the interchange.

Frequently Asked Questions

Q:  I have read on that the project would require taxes to be raised in Orange and Genoa Townships to pay for the project?  Is this true?

A:  First, the website is not affiliated with ODOT or Delaware County in any way.  While some of the statements made on the BigWalnutInterchange are factual and are taken directly from reports created by Delaware County and ODOT, some are either assumed to be true without any supporting facts or are simply false.

The interchange project is proposed to be FULLY funded by Delaware County and ODOT without any financial participation by either Orange or Genoa Township.  No additional tax levies are being considered for this project.  And while no decision has been made yet regarding upgrades to Big Walnut Road, Delaware County routinely partners with townships to assist with funding township road work and has no desire to place a financial burden on either Orange or Genoa Township regarding maintenance of local road infrastructure around the interchange.

In Ohio, the Board of County Commissioners are the local authority that establish and construct new public roads outside of municipalities (except for state routes, which are under ODOT’s jurisdiction).  Townships, by comparison, are charged with maintenance of local roads outside city or village limits which are not added to the county or state route system.  Ultimately, the County Commissioners make the final determination on which public roads are to be maintained by the County, and which are to be maintained by Townships, though this process involves consultation with Township Trustees and the County Engineer, considering factors such as connectivity of the County Road network and the traffic types and volumes on the roads.

If it is necessary to upgrade any township roads (including Big Walnut Road), townships are under no obligation whatsoever to participate or contribute financially to such a project. The County would expect to work with both Orange and Genoa Township if the project is determined to be feasible and upgrades are needed to Big Walnut Road or any intersections along Big Walnut Road.  In such case, one outcome may be for Delaware County to take over maintenance of Big Walnut Road as a county road, and/or potentially other roads in the vicinity of the interchange; however, since no decisions have been made yet on whether the interchange can actually proceed, no decisions have been made yet regarding township road maintenance.

Q:  Why is this project needed?

A:  The project is proposed to improve access to the interstate highway network and other principal highways in the area for the developed areas of suburban Southern Delaware County and to provide a link between Delaware County’s key north-south highway (I-71) and a key east-west arterial roadway system (Big Walnut and Lewis Center Road).

Q:  This interchange is close to existing residences and a school and seems like a terrible location for an interchange. Why can’t you just move it to Plumb Road, Lewis Center Road (east) or Cheshire Road? 

A:  Early in the process of evaluating a possible location for the interchange, the County considered other options such as Plumb Road, Lewis Center Road (east) or Cheshire Road.  Key considerations in locating a freeway exit include spacing along the freeway relative to other interchanges and the suitability of the local road system it is connecting to.

Cheshire Road is located just 1 mile south of the proposed Sunbury Parkway interchange, which will be a companion interchange to the current Exit 131 Sunbury/Delaware exit much like Polaris and Gemini (Exit 121) function together as a single interchange with a single off-ramp from I-71 in each direction.  Having sufficient spacing between interchanges is necessary not only to make the best use of the access point, but also to promote safe merging of traffic that is entering or exiting the highway.  An exit on Cheshire Road would not satisfy this requirement and is simply not feasible at this time.

Plumb Road and Lewis Center Road (east) do fall within an acceptable spacing range between Polaris (Exit 121) and Sunbury (Exit 131), however, these are local roads that begin at Africa Road and end at Old 3C Highway.  To be a viable location for an interchange, the ramps must provide linkage to roads going in each direction.  Because of Alum Creek Lake, there would be no direct link to/from west of Africa Road, forcing traffic to/from the west to go several miles north or south on Africa Road to Cheshire Road or Lewis Center Road (west).

By comparison, the Big Walnut and Lewis Center Road corridor will connect to Home Road at US 23 which extends all the way to Union County.  On the east end, Big Walnut Road extends all the way to Sunbury Road, and with the short jog on Sunbury Road and Red Bank Road across Hoover Reservoir, this corridor reaches Center Village Road which extends all the way to Licking County.

Throughout the growth of Orange and Genoa Townships, efforts have been made to preserve the Big Walnut Road corridor as a viable transportation corridor, whether or not a future interchange would be added. This has included access management (limiting the number and location of new intersections) and reserving right of way and enforcing setbacks from the road for new developments. Through the development that has occurred through the 1990’s all the way to now, each development has been evaluated and measures put in place (to the extent reasonable) to provide for the future traffic growth along this primary east-west corridor, with or without an interchange.

Q:  A new interchange would add so much traffic to Big Walnut Road. How would I get in and out of my neighborhood safely?

A: Due to projected population and traffic growth, upgrades to Big Walnut Road would be needed in any scenario, even without an interchange. Intersection upgrades including roundabouts or traffic signals would be needed at the major cross-road intersections such as Grand Oak/Wilshire Drive. Connectivity between neighborhoods would allow most area traffic to reach this intersection during peak travel hours. For isolated neighborhoods, use of other intersection types such as RCUT’s or Restricted Crossing U-Turn intersections would allow for access during busy travel times. All of these issues will be explored in greater detail during the Feasibility Study.

Q:  I don’t want an interchange here. There are houses and schools nearby. Why aren’t you listening to me?

A: Ultimately, Delaware County and ODOT officials are accountable to our constituents through our elected and appointed leaders. As representatives and residents of this area, or sole motivation is to do the best we can for our community. Sometimes that means doing what isn’t particularly popular at the moment.

Be assured that we are listening. We do our best to listen to resident concerns and come up with solutions and plans to address those issues. Sometimes that means building a project to improve a situation. Sometimes that means doing nothing, either because that is what’s best for now or there just isn’t anything that can be done.

Q:  What’s wrong with the Polaris/Gemini Interchange?  Can’t you just fix that?

A:  While the I-71 and Polaris/Gemini interchange (exit 121) does provide some access to I-71 for residents in southern Delaware County, the existing interchange is severely congested for several hours per day and does not provide reliable or efficient means of accessing the regional transportation network for a large portion Delaware County and the majority of its population.

Even with upgrades being constructed in 2020 and 2021 between Polaris/Gemini and I-270, those changes are primarily intended to improve safety and open the bottleneck on I-71 south of Polaris Parkway to make merging and weaving on I-71 between Polaris and I-270 more safe and efficient.  This project will not address the lack of access and system linkage between the local roadway network and I-71.

Q:  Is this the same thing as the planned Sunbury Parkway Interchange near US 36/SR 37?

A:  No, the Big Walnut Interchange is a separate project with a conceptually different purpose – that is, to serve the transportation needs of current residents and businesses in Orange and Genoa Townships in south-central Delaware County, and the population growth that has already occurred in this area over the last 20 years and to link our existing east-west local roadway network to the interstate highway system.

By comparison, the interchange modification at the Sunbury/Delaware exit (Exit 131) is being developed to address congestion at the existing interchange that is expected to occur over the next 20+ years as new commercial and residential development occurs in the vicinity of that interchange.  For more information about the US 36/SR 37 interchange project, visit ODOT’s project webpage.

Q:  How long has the Big Walnut Interchange been planned?

A:  An interchange in this vicinity was considered as early as 1987 in the Southern Delaware County Thoroughfare Plan, which contemplated an interchange north of the current location of the Polaris/Gemini interchange to serve Alum Creek State Park.  The Polaris/Gemini interchange was eventually built south of the location shown in the thoroughfare plan.

In the late 1990’s, recognizing the massive amount of development that was being planned and built around Polaris, a second interchange for southern Delaware County was proposed farther north of Polaris, in the vicinity of Big Walnut Road.  This was formalized with approval of the 2001 Delaware County Thoroughfare Plan, which shows the interchange at Big Walnut Road.

Q:  Wasn’t this interchange was studied a few years ago? Why isn’t it already built, or why are you continuing to study it?

A:  A study was done by Delaware County in 2006-09 looking at the feasibility of building an interchange at Big Walnut Road.  That study concluded that the interchange would, indeed, serve a lot of traffic; however, the extra traffic using the interchange destined to/from Columbus would require an additional lane to be built on I-71 between Big Walnut Road and Gemini Place and/or I-270 so as not to degrade the traffic operation on I-71, which is an interstate freeway carrying over 80,000 vehicles each day between Ohio and Kentucky.

The estimated cost of this freeway expansion was well beyond any financial means of Delaware County or ODOT at the time, and development of this project was suspended while other projects in the area, including the Gemini/Ikea Way extension, widening of Worthington Road, South Old State Road, Powell Road, Lazelle Road, Cleveland Avenue at I-270, US 23 at I-270 and other roads in the area to enhance already existing means of accessing the interstate highways in the area.

In 2015, Delaware County and ODOT resumed the study of this interchange in light of the fact that many of the local roads near the interchange, and roads leading to Polaris/Gemini had been upgraded or would be upgraded in the near future. In addition, the significant population growth in Southern Delaware County had resumed and even intensified after the 2008 recession, leading to a higher demand for transportation access to the regional highway network.

From 2016-20, Delaware County and ODOT worked through a traffic study and preliminary feasibility study to identify alternatives that would serve the purpose of the project – to provide linkage from the primary north-south freeway in Delaware County (I-71) with the primary east-west corridor (Lewis Center and Big Walnut Roads) in this area.

Q:  Why are you looking at this interchange again?

A: As the other local road network improvements mentioned above have been completed or will be completed in the next few years, and congestion at existing interchanges remains a problem, there are few, if any, other remaining options to improving access to the freeway network besides adding more interchanges.  Projected population growth in Orange and Genoa Townships, as well as continued commercial development in and around the Polaris area, is expected to consume much of the traffic capacity that has been created by other road improvements in the areas, so there will ultimately need to be more points of access to the freeway network for residents of Southern Delaware County.

Q:  Isn’t this project going to cause more development? Why don’t you just stop development so traffic doesn’t get any worse in this area?

A:  This project isn’t designed to facilitate more development.  The location of the interchange is in an area that is mostly already built-out with residences and public uses (Alum Creek State Park).  There is little developable, vacant land near the proposed interchange.  The Big Walnut Interchange project is fundamentally different than the Sunbury Parkway interchange at Exit 131 which is designed to accommodate future development which we know is coming.

As for stopping development, this is neither fair nor legal.  The 14th Amendment to the Constitution and numerous federal and state laws provide individuals due process and equal protection under law.  This includes the right of persons to sell their vacant land, and the right of any person wanting to build new homes or businesses to fair consideration under current zoning laws.  Zoning laws can require reasonable standards for development, but cannot simply prevent development.

Q:  Besides improving access for residents, why is the interchange needed?

A:  Alum Creek State Park is one of Ohio’s top outdoor recreational destinations and a premier location for camping and boating.  The park generates tourism spending in the area and in Ohio which boosts business spending and employment and encourages physical activity to improve health and wellness.  Access to the park, especially for recreational vehicles and vehicles with boats in-tow, is currently not as good as it could be.  The circuitous and congested routes that visitors must take to get to Alum Creek State Park from I-71 using the Polaris-Gemini exit, or from the US 36 interchange in Sunbury, can be improved with an exit that is closer and easier to navigate to reach the major park amenities including the boat launches, campground and below-the-dam park.  In addition, the project would provide bicycle and pedestrian infrastructure which is missing in this area.

Q:  Would the interchange affect traffic on I-71?

A:  Yes. Travel demand modeling shows that more traffic would use I-71 to get to the new interchange and be diverted off parallel routes such as US 23, Cleveland Avenue and other north-south roadways in the area.

In order to mitigate this additional traffic, an additional travel lane would need to be added in the northbound direction on I-71 between Gemini/Ikea Way and the new interchange.  In the southbound direction, traffic may have to be “metered” so as not to degrade traffic flow in I-71, meaning some of the traffic that wants to get on I-71 southbound at the new interchange would have to wait at a ramp meter light, just like some other freeway ramps throughout Central Ohio.

Q:  I’m worried about noise and air pollution around a new interchange.  What will be done to address those issues?

A:  Noise and air pollution are legitimate concerns with any transportation project.  As part of this project, we will study the impacts of the proposed project on adjacent properties.  There are policies in place to address noise, in particular, that could potentially involve mitigating additional noise levels with barriers such as mounds or noise walls if deemed feasible and desired by the properties that are impacted.

Q: Won’t this project put additional demand on public safety services such as police, fire and EMS?

A:  The project will actually provide a valuable access point for first responders to reach incidents on I-71 and for mutual-aid responders from other fire or EMS districts to reach incidents in Orange or Genoa Township.

Q:  Is the Big Walnut Interchange being proposed to serve new commercial development in the area?

A: No. The interchange is being proposed to address needs of existing development within Orange and Genoa Townships as well as Alum Creek State Park.  The area surrounding the proposed interchange is mostly built-out with residential development, or is preserved in perpetuity for public park use within Alum Creek State Park.  There are only a few undeveloped tracts of land remaining in the vicinity of the interchange.  Land use is determined by local zoning regulations and the Orange and Genoa Township Comprehensive plans contemplate mostly rural residential and planned residential development in the remaining undeveloped areas.

Q:  Will the project affect my property value?

A:  Any property owners that have property directly affected by the construction would be compensated for additional land that is needed for the project.

For other properties that are near the interchange but aren’t directly affected by the construction, the relationship of transportation improvements to land value has been well studied but is not well understood.  Ease of access to transportation for jobs and amenities can be one factor that influences property value, but it is not the only factor.

Q:  Where would the ramps to and from I-71 go, and what would the limits of work on the local road network be?

A:  The feasibility study has explored three different conceptual locations for ramps to/from I-71.  Ramp terminals (intersections on the local roads) located on Africa Road north of Big Walnut Road, Africa Road south of Big Walnut Road, or on Big Walnut Road.

For a basis of developing cost estimates and a funding plan, the ramp location on Africa Road north of Big Walnut Road was selected as the most technically feasible location; however, until that alternative has been fully vetted with public review and additional environmental studies, there is no preferred alternative at this time.

The limits of work on the local road network are not known in detail at this time; but the study area of the project extends along Lewis Center Road west to South Old State Road, and on Big Walnut Road east to State Route 3.  The north limit of the study area is Lewis Center Road (East), and the southern limit of the study area is Africa Road at I-71.  It is likely that any local road improvements would be implemented in a phased manner as they are determined necessary based on traffic volumes.

Q:  Are you considering other transportation modes such as bicycling, walking and transit?

A:  Yes.  The project would construct new bicycle and pedestrian infrastructure including paths and sidewalks within the limits of the project, and would provide a connection between residential areas east of I-71 and Alum Creek State Park.  In addition, DCEO has had conversations with the Delaware Area Transit Agency regarding a potential park and ride facility located on Alum Creek State Park property to help promote use of transit and reduce single occupancy vehicle commuters to Columbus.  The park and ride facility would require additional study and is proposed only in concept at this time.

Q:  How will this project be paid for?

A:  The traffic and feasibility studies are being paid for with federal highway Surface Transportation Program funding.  It is anticipated that the acquisition of property and construction of the project would be paid for with a combination of local, state and federal transportation funding.

2020 Feasibility Study Draft

You can download the 2020 Draft Feasibility Study here.  Please note that this study has not been approved by the Ohio Department of Transportation or Federal Highway Administration.

2020 Draft Feasibility Study Report (5.42 MB)

2020 Draft Feasibility Study Appendices (87.7 MB)

Project Schedule

Preliminary Traffic Analysis and Feasibility Study: 2016-20

Revised Traffic Analysis: 2022-23

Final Feasibility Study (if Revised Traffic Study shows the project can meet technical requirements for traffic): 2024+

Preliminary Engineering (if project advances): 2025+

Property acquisition (if project advances): 2026+

Construction: To Be Determined

Estimated Project Cost

The preliminary cost estimate for the project is $98 million which includes the local road improvements in the vicinity of the interchange on Africa, Big Walnut and Lewis Center Roads as well as adding a fourth lane to I-71 from Gemini Place to the proposed interchange at Big Walnut Road.

Questions or Comments?

Your comments or suggestions are important and we would like to hear from you about the project. Please contact Robert Riley, Chief Deputy Engineer at 740-833-2400 or send your questions or comments to