SUPERSTREETS IN TEXAS. ITS Texas Annual Meeting San Marcos, Texas Session 6A - Operations November 11, 2011

Transcription

1 SUPERSTREETS IN TEXAS ITS Texas Annual Meeting San Marcos, Texas Session 6A - Operations November 11,

2 Superstreet Corridor Location 2

3 3 US Highway Looking south above Evans Road, pm peak

4 Why? Traditional Intersection Traditional Intersections allow left-turns from all approaches and for simplicity 4 basic signal phases: 1. Left Turns on Major St 2. Throughs on Major St 3. Lefts on Cross St 4. Throughs on Cross St 4 While this provides freedom of movement it increases delay time and congestion. The intersection area is shared using time to separate the movements.

5 Innovative Intersections Innovative Intersections reduce the number of signal phases to increase operational efficiency by removing or redirecting some or all left-turns. Fewer signal phases = lower the delay to drivers. Innovative Designs also reduce the number of conflict points, increasing intersection safety. 5

6 6 What is a Superstreet - Superstreet Intersection, Restricted Crossing U-Turn (RCUT)

7 7 Superstreet Vehicle Movements

8 8 2-Lane Turnaround

9 9 2-Lane Turnaround

10 Intersection Safety Conflict Points Conventional Intersection Superstreet Intersection 10

11 Latest US 281 Superstreet Crash Data Before Jan 2007 June 2009 After Nov 2010 Sep 2011 Total Crashes 1, Number of Months Average # per Month (-45.8%) Fatals per month Injury per month (-20.8%) PDO per month (-55.9%)

12 US 281 at Evans Road Evening Peak Before Condition 12

13 US 281 at Evans Road Evening Peak Superstreet 13

14 Advantages of Superstreet Intersections Improved Signal Progression along Main Road Travel Time Savings Reduced Emissions and Fuel Consumption Delay Savings Access Control Features Inherent in Design Reduction of Intersection Conflict Points Flexibility in Turnaround Location Relatively Simple Design Turn Lanes Traffic Signals 14

15 Superstreet Traffic Signal Efficiency Benefits Simple 2-phase Signals vs. Multi-phase = lower delay Conflicting Signal Movements Separated with Time and Space; not only time Less Lost Time per Cycle More Green Time for Main Street & Cross Street Movements Results in Two One-way Streets Much easier to progress traffic through green lights 15

16 Summary of US 281 Superstreet Benefits Fits in Existing Right-of-Way Safety Conflict Points Cut in Half Crossing Conflict Points Significantly Reduced Saves 1,050,852 Vehicle-hours per Year AM Peak 65 percent delay reduction PM Peak 73 percent delay reduction Saves 1,120,522 Gallons of Fuel per Year $24.6 Million in Benefits/year (Delay, Fuel, Stops) Construction Cost $5.2 Million One Year Benefit:Cost =

17 Potential Project Challenges Indirect Pedestrian Path Potential Driver Confusion Truck U-Turns Speeds Along Major Roadway Construction Phasing 17

18 ITS Elements IP Based Communication - Wireless Network IP - Conflict Monitor, Detectors, Controllers Radar Based Vehicle Detection on Major Roadway for Dilemma Zone Protection Radar Based Detection for Presence Detection Battery Backup Systems CCTV Cameras w/ PTZ Advanced Controllers But simplified Application 18

19 Actual Results Evening Peak Hour Traffic Volumes US 281 at Evans Road Before After (Superstreet) Northbound US 281 2,811 4,533 (61% increase) Southbound US 281 2,030 2,391 (18% increase) Eastbound Evans Road (no change) Westbound Evans Road (13% decrease) Total Intersecting Traffic 6,082 8,090 (33% increase) 19

20 Peak Hour Travel Time Between Lp 1604 & Bulverde Rd (6.1 mi.) Before* (min) Avg. Speed AM Southbound mph PM Northbound mph Goal (min) After* (min) Avg. Speed mph mph % Improvement 19% 34% *Official travel time measurements gathered by TxDOT For comparison, Free Flow Travel Time (no traffic, no signals, at posted speeds) = 6.7 min (55 mph) 20

21 US 281 Observations Flow Rates for Northbound 281 at Evans in Evening Peak Before Superstreet Through vehicles = 850 vehicles per hour per lane After Superstreet Through vehicles = 1,500 vehicles per hour per lane >75% Increase in Flow Rate 21

22 Media Reports 22 22

23 Media Reports 23

24 Why A Superstreet? Low-cost improvement No additional through lane capacity No additional right-of-way needed Simple environment documentation and clearance process Improved traffic flow shows great return on investment (benefit:cost) Improved Safety Relatively quick construction 24

25 Where this concept is applicable Major signalized urban/suburban arterials Limited funding for major improvements Limited opportunity for right-of-way expansion Right-of-Way (150+ ft) Environmental concerns 25

26 Operational Superstreets in Texas US 281 North, San Antonio 3 RCUT + 1 MUT Lp 1604 West, San Antonio 2 RCUT + 1 MUT Design SH 71 at FM 973, Austin 2 RCUT Studies Underway in Austin & San Antonio Consideration in other areas

27 27 Lp 1604 at Shaenfield 1 of 3

28 28 Lp 1604 at Shaenfield 2 of 3

29 29 Lp 1604 at Shaenfield 3 of 3

30 Questions? Contact: Gilmer D. Gaston, P.E., PTOE Pape-Dawson Engineers, Inc. 555 E. Ramsey San Antonio, Texas T: e: 30