1. November 5, 2010 ITSO Trans Talk Vern Swing, P.E. & Steve Manhart, P.E., PTOE, PTP November 5, 2010 -- University of Minnesota DIVERGING DIAMOND INTERCHANGE (DDI) DESIGN (DDI) DESIGN

2. Presentation Outline Interchange Types Case Study - Elk Run Interchange Diverging Diamond Interchange Design Characteristics Advantages Use in North America Questions

3. Interchange Types Basic Diamond

4. Interchange Types Diamond System Interchange

5. Interchange Types Full Cloverleaf

6. Interchange Types Partial Cloverleaf (Parclo)

7. Interchange Types Partial Cloverleaf (Parclo)

8. Interchange Types Trumpet

9. Interchange Types Directional T

10. Interchange Types Single-Point Urban Interchange (SPUI)

11. Interchange Types Roundabout

12. Interchange Types Large Radius Roundabout

13. Interchange Types Diverging Diamond Interchange

14. Diverging Diamond Interchange (DDI) Springfield, MO

15. Diverging Diamond Interchange (DDI)

23. Interchange Conflict Points

24. Intersection Conflict Points

25. Diverging Diamond Interchange (DDI) AdvantagesAdvantages Improved Safety Operationally More Efficient Expandability Can be more cost-effective (especially when retrofitting an existing diamond interchange to DDI)

26. Case Study: TH 52 Elk Run Interchange Project Interchange Design Project Estimated Cost: $36 Million Total Project Cost

27. Elk Run Interchange Project Project Development Area

28. Elk Run Interchange Project Mn/DOT S.P. 2505-48 (TH 52)

29. Elk Run Interchange Project Mn/DOT S.P. 2505-48 (TH 52)

30. Elk Run Interchange Project Mn/DOT S.P. 2505-48 (TH 52)

31. Elk Run Interchange Project Mn/DOT S.P. 2505-48 (TH 52) Interchange Options Considered Large Radius Roundabouts Smaller Radius Roundabouts Single-Point Interchange Diverging Diamond Interchange - DDI (NOTE: FHWA refers to DDI as Double Crossover Diamond – DCD)

32. DDI Proposed Layout at Elk Run

34. Diverging Diamond Interchange (DDI) Q) Are there headlight concerns, since traffic is directly in front of each other before the crossovers? A) No. The direct headlight approach is a further distance than a common scenario where a left turn lane is directly opposite the opposing left turn. The headlights do not affect the crossover movements since vehicles are angled away from each other at the crossovers. Putting up any type of headlight shields (also known as glare screens) on the curb is ill-advised since there will be a in safety due to poor sight distance.

35. SYNCHRO/SimTraffic Analysis of DDI

37. Proposed Elk Run DDI Findings Mn/DOT proposed diamond interchange layout reaches maximum capacity at 40% build-out. Proposed DDI layout reaches maximum capacity at 79% of build-out. ► DDI Concept was ultimately selected by Mn/DOT.

38. DDI from the Air – Springfield, MO

39. Driving a DDI – Springfield, MO

40. Use in North America I-44 & MO-13, Springfield, MO I-15 & Main St, American Fork, UT I-15 & 500 East, American Fork, UT I-70 & Woods Chapel Rd, Kansas City, MO I-435 & Front St, Kansas City, MO Botts Rd & M-150, Kansas City, MO I-270 & Dorsett Rd, St. Louis Co, MO Along Baltimore-Washington Pkwy, Anne Arundel Co, MD Hwy 427 & Rathburn Rd, Toronto, ON I-5 & Fern Valley Rd, Phoenix, OR New Circle Rd Interchanges, Lexington, KY I-590 & Winton Rd, Rochester, NY I-75 & US 224/SR-15, Findlay, OH I-480 & Tiedman Rd, Brooklyn, OH Ashford-Dunwoody Rd Interchange, Atlanta, GA 8 Interchanges in/around Atlanta, GA West Catawba/Exit #28, Charlotte, NC I-95 & Thurbers Ave, Providence, RI IL-59 & I-88, Naperville, IL US-129 Bypass / Bessemer St/ Middle- settlements Rd Interchange in Alcoa, TN

41. Questions? Vern Swing, P.E. Principal Transportation Engineer/ President RLK Incorporated vswing@rlkinc.com Steve Manhart, P.E., PTOE, PTP Sr. Transportation Engineer II RLK Incorporated smanhart@rlkinc.com 6110 Blue Circle Drive, Suite 100 Minnetonka, MN 55343 952-933-0972 www.rlkinc.com