Innovative Intersections Presented by: Matt Crim P.E., PTOE Stantec Consulting Services Inc. October 29, 2015

Transcription

1 Innovative Intersections Presented by: Matt Crim P.E., PTOE Stantec Consulting Services Inc. October 29,

2 Traditional Intersections Traditional Intersections allow left turns from all approaches. 1 2 There are four basic signal phases: 1. Left turns on Major St. 2. Throughs on Major St 3. Left turns on Minor St 4. Throughs on Minor St 3 4 2

3 Traditional Intersections Phase, Phase, Everywhere a Phase 30% 20% 30% 20% 50% 20% 4 Phase Signal 30% 70% 30% 3 Phase Signal 2 Phase Signal 3

4 Traditional Intersection Safety Angle crashes account for 40% of fatal crashes at intersections 32 Conflict Points Left turn crashes account for 20% of fatal crashes at intersections 4

5 What Are Innovative Intersections? Intersections that: Improve the way traffic makes certain movements by eliminating, relocating or modifying conflict points Improve the signalization by reducing cycle lengths and the number of phases Improve travel time and reduce delay 5

6 Innovative Intersections Superstreets Continuous Flow Intersection (CFI) Diverging Diamond Interchange (DDI) Single Point Urban Interchange (SPUI) Median U-Turn Crossover Roundabouts Jughandle Quadrant Intersection 6

7 Superstreet Intersections in the U.S. (aka J-Turn, Restricted Crossing U-Turn, Reduced Conflict Intersection) States with Superstreet Intersections Source: FHWA Restricted Crossing U Turn Informational Guide 7

8 Superstreet Intersection Traditional Intersection Superstreet Intersection 8

9 Superstreet Signal Phasing Phase 1 Mainline Mainline Through and Right-Turn Side Street Phase 2 Mainline Mainline Left-Turn and U-Turn Side Street Right-Turn Side Street 9

10 Comparison of Conflict Points Conflict Type Four-Leg Signalized Intersection Superstreet Intersection Merging/Diverging Crossing (left turn) 12 2 Crossing (angle) 4 0 Total

11 Superstreet Safety Benefits Reduced collisions for total, angle and right turn, left turn, and fatal and injury Total collisions reduced by 46% Collision Type Crash Reduction Fatal and I njury 63% Angle and Right Turns 75% Left Turns 59% Rear Ends 1% Sidesw ipes 13% Other 15% Total 46% Source: N.C. State University Research Project

12 NC Peanut Plant Road NC 87 at SR 1150-Peanut Plant Rd NC 87 Bypass was opened in Total Crashes and 5 Fatal Crashes in 8 years after completion 12

13 NC Peanut Plant Road Collision Diagram 13

14 NC Peanut Plant Road 3 Years Prior to Superstreet: 24 Total Crashes 8 Crashes per Year 19 T-Bone Crashes (w/injury) 6.33 Crashes per Year 1.5 Years After Superstreet: 2 Total Crashes 1.33 Crashes per Year No T-Bone Crashes (w/injury) 0 Crashes per Year 14

15 Superstreet Semi-Trailer Accommodations 15

16 Superstreet Pedestrian Accommodations Source: FHWA Restricted Crossing U Turn Informational Guide 16

17 Superstreet Pedestrian Safety Source: FHWA Restricted Crossing U Turn Informational Guide 17

18 Superstreet Feasible Demands Source: FHWA Restricted Crossing U Turn Informational Guide 18

19 Continuous Flow Intersection (CFI) (aka Displaced Left Turn or Crossover Displaced Left) Major Street Movements Minor Street Movements 19

20 CFI History Concept Developed over 30 years ago AASHTO s 2002 National Award for Innovation Currently Constructed in Colorado Missouri Louisiana Maryland Mississippi Ohio Texas Utah Under Design for Construction Florida North Carolina Georgia Virginia 20

21 CFI Basics 21

22 CFI Signal Phasing Advance CFI Traffic Signal Advance CFI Traffic Signal Center CFI Traffic Signal Advance CFI Traffic Signal Advance CFI Traffic Signal 22

23 CFI Efficiency Conventional 4-lane roadway 650 v/l/h x 4 lanes = 2600 v/h C=150 P.M. Peak CFI 4-lane roadway 850 v/l/h x 4 lanes = 3400 v/h C=120 P.M. Peak 23

24 Comparison of Conflict Points Source: FHWA Signalized Intersections: Informational Guide Conflict Type Four-Leg Signalized Intersection Partial CFI Intersection Merging/Diverging Crossing (left turn) 12 6 Crossing (angle) 4 10 Total

25 Airline Sherwood Forrest Blvd CFI Operational Benefits: Travel Times reduced by 40% Delay reduced by 50% Crash Rate Reduction: From 10 per million vehicle miles (MVM) to 4 per MVM 25

26 Public Acceptance Question: Do the improvements make TRAFFIC CONGESTION Better, Worse, or the Same? 26

27 Public Acceptance Question: What is your level of Satisfaction with the current traffic conditions of the intersection? 27

28 Diverging Diamond Interchange (DDI) (aka Double Crossover Diamond) 28

29 Diverging Diamond Interchange (DDI) 29

30 Where did the DDI come from? Le Perreux sur Marne, France Versailles, France Seclin, France 30

31 DDI Signal Phasing Phase 1 Phase 2 31

32 DDI Cost Benefits Interchange Location DDI Cost (real or estimated) Alternative Design Cost Cost Savings I-44/Route 13 Springfield, MO $3.2 Million Over $10 Million $6.8 Million I-435/Front Street Kansas City, MO $6.7 Million Diamond: $11.4 Million SPUI: $25 Million $ Million SR 265/SR 62 Utica, IN $52 Million $118 Million $66 Million I-590/Winton Road Brighton, NY $4 Million SPUI: $10 Million Triple Left Diamond: $13.6 Million $6-9.6 Million Retrofit Existing Bridge can usually be used Additional R/W rarely needed Construction time is reduced Maintenance of traffic simplified during construction New Interchange Fewer lanes than other interchange forms Less bridge structure Less R/W than a cloverleaf 32

33 DDI Awards Popular Science s Top 100 Innovations for 2009 AASHTO s 2010 National Award for Innovation 33

34 US Kentucky 4 DDI 34

35 US Kentucky 4 DDI 35

36 Comparison of Conflict Points DDI 2 crossing conflict points Traditional 4 crossing conflict points 36

37 US Kentucky 4 DDI Safety Pre DDI Post DDI 37

38 Public Acceptance Question: Overall, do you think this project was a good transportation solution for this location? 72% 38

39 Public Acceptance Question: Do you think a DDI should be considered at other locations in Lexington or elsewhere in Kentucky? 72% Yes No 39

40 6. Better access management 7. Attracts investment to revitalize struggling areas 8. Many designs are aesthetically pleasing 9. Improves quality of life 10. High return on investment

41 1. Better mobility enhances the local economy 2. Fewer conflicts and less congestion improve safety 3. Avoids street widening and even grade separation 4. Reduces right-of-way impacts 5. More feasible to convert general purpose lanes into other uses such as transit only lanes