Business Access and Associated Benefits Provided by Roundabouts

Transcription

1 Business Access and Associated Benefits Provided by Roundabouts MTJ Roundabout Engineering Mark Johnson, PE ITE Rapid City July 1 st 2014 ROUNDABOUT ANALYSIS, PLANNING, DESIGN, OUTREACH, EDUCATION

2 Introduction

3

4 Introduction

5 Introduction

6 Traffic Planning with Roundabouts Roundabout Operational Characteristics Allow for: o Capacity at Intersection = Less Roadway Widths o Roadway Geometric Flexibility due to slower speeds o Intersection Spacing Versatility o Different Access Control Opportunities

7 Traffic Planning with Roundabouts

8 Traffic Planning Examples with Roundabouts Example Project: Huffman Road Corridor, Anchorage, AK o No Roadway Widening (3 Lanes) = const. within Ex. OW o Access Control Opportunities = Good Business Circulation o Improved Traffic Flow and Safety

9 Traffic Planning with Roundabouts 7 Lane Cross Section Flared Entries, Lane drop at Exit 2 Lane Cross Section 7 Lane Cross Section

10 Case Studies

11 Roundabout Design Case Study Mt Horeb, WI

12 STH 78/92 Mount Horeb, Wisconsin 2,000 VPH, 2,800 design Flared Two - lane entry Two- Thru lanes WB * Flared Two - lane entry, RT only Varying circulating width * * * * * * Single-lane entry Two-lane Tapered Exit * Business Access *

13 Mount Horeb, Wisconsin STH 78/92 Pedestrian Comparison 60s Signal 18s Roundabout

14 Mount Horeb, Wisconsin STH 78/92 Trucks

15 Mount Horeb, Wisconsin

16 Traffic Planning with Roundabouts ~30k ADT ~25k ADT 4 Lane 2 Lane Mt Horeb, Wisconsin

17 Roadway Planning 9 Lane Structure

18 Roadway Planning 3-4 Lanes ROW Saved

19 Traffic Planning Experience with Roundabouts ROUNDABOUT ANALYSIS, PLANNING, DESIGN, OUTREACH, EDUCATION

20 Traffic Planning with Roundabouts Development

21 Traffic Planning with Roundabouts 600,000 square foot mixed retail development, Green Oak Village Place

22 Traffic Planning with Roundabouts ~

23 Small Commercial Development Questions ~600 Grocery Store

24 Small Commercial Development

25 Small Commercial Development Questions ~600

26 Small Commercial Development Questions ~600

27 Questions

28 Business Access 125 ICD Short Flared Two-Lane Entry Single-Lane Entry Aux RT Lanes (two types)

29 Redevelopment Monona, WI

30 Redevelopment Full or LT Access Precluded by proximity to signal Proposed Super Center 225,000 sq ft. $30M Project Vacant Land Assessed = $6M

31 Redevelopment * Business Access

32 Redevelopment 135

33 Two-lane approach Trucks One-lane approach Source: MTJ

34 Redevelopment

35 Trucks Video Taken From Here Source: MTJ

36 Effective Lane Utilization with Flared Entry Design

37 Project Area 1/28/14 37

38 Proposed Project California Boulevard Roundabouts City of Napa 1/28/14 38

39 Directional Signing-Way Finding

40 HISTORIC DOWNT OWN Directional Signing- Simplified Entry HISTORIC DOWNT OWN Downtown Napa To Downtown Downtown Napa 1/28/14 40

41 Omni-Means - Built to Deliver 1/28/14 41

42 Omni-Means - Built to Deliver 1/28/14 42

43 Ramp Intersection Design Optimization Lane Drop/Merge in close proximity Accepting lane not readily visible to turning traffic High speed lane drop (with green light) 2 Lanes of traffic & short decision distance from ramp entrance Poor sight lines to approaching traffic 1/28/14 43

44 Ramp Intersection Design Optimization Acceleration Lane to Accommodate Merge (35mph) Lower Exit Speeds from Roundabout (<25mph) with Lane Drop Completed Prior to Merge (30mph) Simplified Decision Making Single EB Thru Lane with designated right turn pocket and improved sight lines = easier decision making 1/28/14 Raised Median Designates Pocket = Driver Comfort 44

45 Traffic Planning with Roundabouts Summary o Roundabout Operational Characteristics Allow for: o Capacity Improvement with Reduced Roadway Widening o Intersection Spacing Versatility o Access Control Opportunities for Improved Business Access and circulation o Need further US research and publication to document these differences. o Need Research and Industry Documentation to Codify Roadway Planning Criteria for Roundabout Intersections

46 Thank You/Questions MTJ Roundabout Engineering Mark Johnson, PE