Unconventional Interchange and Intersection Design 1 and 2
April 12 and 19, 2022
7:45am – 4:00pm


Unconventional Interchange and Intersection Design 1 on April 12

Many arterials and interchanges are terribly congested, and conventional measures offer little prospect for relief.  Unconventional designs offer some potential for relatively inexpensive improvements to those congested arterials and interchanges.  These are designs that have been used in some state or have been researched but have not been placed into widespread use.  Examples include the superstreets (RCUTs, j-turns) being installed in North Carolina, the median u-turns that Michigan has used for many years, and the diverging diamond interchanges that have recently opened in over 20 states.  In the right place with the details designed well, an unconventional design can deliver safety, efficiency, environmental, and cost benefits to motorists and transportation agencies.

The purpose of this workshop will be to discuss the best of the unconventional intersection and interchange options in some depth.  We will explore the history, planning, design, and operation of the major designs.  By the end of the workshop attendees should understand which design has a realistic chance to help in a particular spot.

This hybrid online class will combine both live instruction and independent online work that you will complete during the day.  Independent work will include quizzes, readings, videos and short assignments.  Access to a computer with a webcam (either a camera that is built into your laptop or one that connects via USB), a reliable internet connection and a workspace that is free from distraction and noise will set you up for success.

Learning Modules:

Module 1: Why Alternative Designs? / Median U-Turn
Module 2: Reduced Conflict Intersections
Module 3: Continuous Flow Intersections and Quadrant Roadway Intersections
Module 4: Intersection and Grade Separated Intersections & DDI


Unconventional Interchange and Intersection Design 2: Case Studies on April 19

The unconventional intersection and interchange workshop offered the day prior to this lab will cover the fundamentals of unconventional intersections and interchanges in a lecture format.  The purpose of the follow-up laboratory is to provide attendees the chance to work through hands-on examples and apply the principles discussed at the workshop.  The lab will begin with a review of the tools on hand to analyze intersection and interchange alternatives.  Then, each attendee will work on one surface-street intersection, one grade-separated intersection example, and one interchange example.  Attendees will work together in small teams to develop potential solutions and then will discuss their potential solutions with the larger group.  Cases examined during the lab are drawn from the ones that the instructor has worked on at the NCDOT; the cases are meant to be challenging, with no easy answers, but not impossible.  By the end of the lab attendees should have the skills and confidence to tackle their own challenging intersection and interchange projects.

Learning Modules:

Module 1: Available Tools

Module 2: Intersection Case

Module 3: Grade-separated Intersection Case

Module 4: Interchange Case

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