Two alternatives were developed for this project:

Alternative 1:   Diverging Diamond Interchange (DDI)    Selected as Preferred Alternative

A Diverging Diamond Interchange (DDI) allows both directions of traffic to temporarily cross to the left side of the road. It moves high volumes of traffic through an interchange without increasing the number of lanes and traffic signals. This movement provides easier access to an interstate.

It also :

  • reduces congestion by allowing traffic to keep moving through an interchange
  • improves safety by allowing  free flowing turns when entering and exiting an interstate, eliminating the left turn against oncoming traffic and limiting the number of traffic signal phases

Diverging Diamonds are easy to navigate, eliminate last-minute lane changes, and provide better sight distance at turns.





Alternative 2:   Partial Clover Interchange

This alternative would be a modification of the existing interchange.  

  • A loop ramp would be added for traffic exiting I-40 westbound to travel southbound on Airport Boulevard.
  • The off and on ramps from and to I-40 Westbound on the north (Airport) side of the interchange would be realigned and moved farther from the bridge structure.

It should be noted that either design alternative requires construction of a new structure over I-40 that will provide for future expansion. 

Access Management techniques will be included along Airport Boulevard to assist in the relief of traffic congestion.

Construction of an auxiliary lane between Airport Boulevard and I-540 is also included in this project.


Access Management (AM) is a set of techniques that State and local governments can use to control access to highways, major arterials, and other roadways. The benefits of access management include improved movement of traffic, reduced crashes, and fewer vehicle conflicts.

Techniques include: 

  • Increasing spacing between signals and interchanges
  • Driveway location, spacing and design
  • Use of exclusive turning lanes
  • Median treatments including 
    • two-way left turn lanes (TWLTL) which are center lanes that allow turn movements in multiple directions
    • raised medians to prevent movements across a roadway
  • Service and frontage roads
  • Land use policies that limit right-of way access to highways

Installing raised medians often raises serious concerns by the business community that local businesses dependent upon pass-by traffic (especially gas stations and fast-food restaurants) will be adversely affected by medians.  Though there are few studies of the actual impacts of medians on business sales, there are several surveys of business owner opinions. 

Surveys conducted in multiple corridors in Texas, Iowa, and Florida demonstrate that the vast majority of business owners believe there have been no declines in sales, with some believing there are actually improvements in business sales. 

One study in Texas indicated that corridors with access control improvements experienced an 18 percent increase in property values after construction. 



 Milestone        Estimated Amount*
  Right of Way Acquisition  $        920,000  
  Construction Costs  $   33,300,000  
  Total Cost  $    34,220,000  

* Estimated Costs as shown in Current 2018-2027 STIP and are subject to change


The NCDOT project team will review all feedback – regardless of how it is submitted (online, phone, email, or letter) – and explore options to incorporate comments and address concerns where and when feasible.  


NCDOT conducted an open house public meeting on January 30, 2018 from 4-7 P.M. at La Quinta Inn and Suites in Morrisville to:

  • Present alternative designs for the project
  • Provide information and answer questions
  • Obtain input on the alternatives

NCDOT staff was available to discuss the alternatives and answer questions.   The public comment period closed on February 14, 2018.

Public Meeting Maps

Alternative 1: Diverging Diamond Interchange also referred to as a DDI Selected as Preferred Alternative 

Alternative 2: Partial Clover interchange 


The public comment period closed on February 14, 2018.  All comments were reviewed and suggestions/recommendations were incorporated into designs where feasible. 



Liam Shannon 

1576 Mail Service Center
Raleigh, NC 27699-1576


Questions regarding this project can be emailed to



Although the N.C. Department of Transportation works to minimize the number of homes and businesses displaced by a road project, it is inevitable, in many cases, that a certain amount of private property is needed. The following information explains right of way acquisition and answers questions about the process.  

Right-of-Way Brochure Single Page Layout      Folleto del Proceso de Adquisición de Bienes Raíces
Right-of-Way Frequently Asked Questions

Right of way Acquisition Process Videos

English                                                                     Spanish


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