update on restricted crossing u-turn intersections

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  • Update on Restricted Crossing U-Turn Intersections

    Joseph E. Hummer, Ph.D., P.E.

    Professor and Chair, Department of Civil and Environmental Engineering

    Wayne State University, Detroit, MI

    And

    James H. Dunlop, P.E.

    Congestion Management Engineer

    North Carolina Department of Transportation, Garner, NC

    For WTS Connecticut

    October 9, 2014

  • Presentation Objectives

    Introduce RCUT

    Summarize recent research and

    implementation progress

    Provide guidance on where RCUT might work

    Inspire you to consider RCUT

    2

  • A.k.a. superstreet, j-turn, restricted crossing

    intersection, synchronized street

    RCUT

    3

  • Three types of RCUT intersections

    Signalized

    Stop-controlled (right)

    Merge- or yield-controlled

    Variations

    4

  • Conventional intersection

    32 conflict points

    RCUT intersection

    14 conflict points

    Why the RCUT Works

    5

  • Progression

    Perfect in both directions!

    100% bandwidth efficiency

    Any speed!

    Any signal spacing!

    Why the RCUT Works

    6

  • Pedestrians

    Why the RCUT Works

    7

  • Does not need large ROW

    Superb access to businesses and side streets

    Easy to navigate

    Why the RCUT Works

    8

  • Invented by Kramer, late-1980s

    Developed independently in MD (1990), MI

    (1994), and NC (2000)

    NC currently leads

    Not the same design as

    median u-turn (Michigan Left)

    History

    9

  • Rural, four-lane divided major road, two-lane

    undivided minor road

    Large sample sizes, before-and-after,

    adjustments for biases

    Safety Findings

    10

  • North Carolina study

    Collision Types

    11

  • Unsignalized

    Site Application US 23/74 Sylva NC

    12

  • NC 87 at SR 1150-Peanut Plant Road

    NC 87 at US 701

    NC 87 Bypass was opened in 1997

    60 Total Crashes and 5 Fatal Crashes in

    8 Years after completion

    Site Application NC 87 at Peanut Plant Rd

    13

  • NC 87-

    Peanut Plant Road

    Collision Diagram

    Site Application NC 87 at Peanut Plant Rd

    14

  • Traffic signals dont

    always solve the

    problem, they may

    just create a

    different problem!

    NC 87- US 701

    Collision Diagram

    Site Application NC 87 at Peanut Plant Rd

    15

  • Site Application NC 87 at Peanut Plant Rd

    Previous Solution: Build an Interchange

    US 17 Shallotte NC 16

  • Final Superstreet Configuration

    Site Application NC 87 at Peanut Plant Rd

    17

  • Countermeasure Relocate leg of SR 1150 Superstreet

    Site Application NC 87 at Peanut Plant Rd

    18

  • Crash Summary Table Superstreet - Before to After

    Before (3 Yrs)

    3/1/2003-2/28/2006 Total Crashes

    Crashes/

    Yr

    24 8.00

    Total Injury

    Crashes

    Crashes/

    Yr

    21 7.00

    Frontal Impact

    Crashes

    Crashes/

    Yr

    22 7.33

    Frontal Impact

    Injury Crashes

    Crashes/

    Yr

    19 6.33

    After (1.5 year update)

    9/1/2006-2/29/2008 Total Crashes

    Crashes/

    Yr

    2 1.33

    Total Injury

    Crashes

    Crashes/

    Yr

    0 0.0

    Frontal Impact

    Crashes

    Crashes/

    Yr

    1 0.67

    Frontal Impact

    Injury Crashes

    Crashes/

    Yr

    0 0.00

    Site Application NC 87 at Peanut Plant Rd

    19

  • 20 US 1 Lee and Moore Counties, NC

    Site Application US 1

  • Crashes Injuries Fatalities

    Location Before After Before After Before After

    1 20 31 10 17 1

    2 12 25 5 13

    3 12 22 7 10

    4 55 49 23 17 1

    5 10 15 5 7

    6 6 12 4 5 1

    7 9 20 4 5

    8 6 10 1 6 1

    9 30 33 19 11 2

    10 12 23 5 13 1

    11 8 37 5 17

    12 17 25 12 18 2

    Totals 197 302 100 139 6 3

    Results 53% Increase 39% Increase 50% Decrease

    Installing Traffic Signals Crashes Injuries Fatalities

    Location Before After Before After Before After

    1 21 8 13 5 2

    2 27 4 16 1

    3 36 10 23 3

    4 58 16 28 10

    5 20 5 3 1

    6 48 20 16 0

    7 28 7 15 4

    8 30 14 18 4 1 1

    9-1 0 2 0 0

    9-2 1 2 0 0

    9-3 0 2 0 0

    9-4 10 12 7 5

    9-5 9 3 7 1

    9-6 0 1 0 0

    9-7 1 1 0 0

    9-8 14 8 9 4 2 1

    9-9 0 1 0 0

    Totals 303 116 155 38 5 2

    Results 62% Decrease 75% Decrease 60% Decrease

    Installing Directional Crossovers

    Directional Crossover Vs. Traffic Signal

    21

  • Planning level

    Critical lane method

    CAP-X

    Detailed level

    VISSIM or other simulation

    Has been calibrated

    Great animation

    Macroscopic level

    Capacity Analysis

    22

  • NCDOT study used calibrated VISSIM model to show 20% overall travel time improvement

    Field study from TX:

    Metric Before RCUT After RCUT

    Southbound travel time

    (morning rush hour)

    23.3 minutes 13.9 minutes

    Southbound average speed

    (morning rush hour)

    16 mph 20 mph

    Northbound travel time

    (evening rush hour)

    19.2 minutes 12.7 minutes

    Northbound average speed

    (evening rush hour)

    19 mph 29 mph

    Traffic count

    (vehicles per day)

    60,100 74,000 63,600 81,500

    Capacity Results

    23

  • Site Application US 15-501 Chapel Hill

    24 42,000 ADT on Four-Lane Expressway 6-Phase Split Side Street Signal

  • 2005 TSIS-Corsim Comparison Before (Traditional Intersection) vs.

    After (Superstreet Intersection) T

    raditio

    nal

    Supers

    treet

    25

  • Avg.

    Speed LOS

    Avg.

    Speed LOS

    Avg.

    Speed LOS

    Avg.

    Speed LOS

    Avg.

    Speed LOS

    Avg.

    Speed LOS

    2005 11.0 F 9.4 F 14.1 F 11.9 F 29.1 C 26.7 D

    2006 27.0 C 24.0 D

    2007 25.0 D 22.0 D

    2008 23.0 D 21.0 D

    2009 21.0 D 19.0 E

    2010 29.1 C 17.9 E

    2011 19.0 E 17.0 E

    2012 18.7 E 15.5 F

    2013 18.5 E

    2014 19.3 E

    2015 17.7 E

    2016 18.2 E

    2017 16.9 E

    2018 17.1 E

    2019

    2020

    2021

    2022

    2023

    2024

    2025

    Lifespan by

    Peak (years) 13 70 1 0 1

    Ye

    ar

    "No Build" Proposed Superstreet

    AM PM AM PM AM PM

    Preliminary Level of Service Analysis

    Site Application US 15-501 Chapel Hill

    26

  • Site Application US 15-501 Chapel Hill

    Pedestrian Crossing Movements

    27

  • Superstreet Project Visualization - 2002

    Site Application US 15-501 Chapel Hill

    28

  • US 15-501 Chapel Hill, NC During construction 2007

    Site Application US 15-501 Chapel Hill

    29

  • 30

    Site Application US 15-501 Chapel Hill

    US 15-501 Chapel Hill, NC After construction 2010

  • Capacity Extend Life of Corridor 7-12+ years

    60% reduction in Travel Time

    220,000 kg Emissions Reduced Annually

    Site Application US 15-501 Chapel Hill

    31

  • 32

    Four-lane divided expressway

    corridor

    Before: no signals, little side street

    traffic

    After: Large residential

    developments, three commercial

    centers

    Improvements paid for by three

    developments in one construction

    project

    28-42% travel time savings on US 17

    through movements

    Extended from 3 to 5 intersections

    Site Application US 17 Leland

  • 33

    Site Application US 17 Leland

  • Comparison of Superstreet and Traditional Intersection

    Corridors

    US 64 Cary US 17 Leland Percent

    Traditional Superstreet Difference

    7/1/2006-6/30/2009 +/-

    Total Crash Rate 308.5 180.0 -41.7%

    Total Crashes/Mile 125.1 84.8 -32.2%

    Intersection Crashes 177.0 95.0 -46.3%

    Total Crash Severity Index 4.6 5.0 8.2%

    Fatal Injury Crashes/Mile 0.9 0.8 -11.1%

    Class A Injury Crashes/Mile 1.8 0.8 -55.6%

    Class B Injury Crashes/Mile 6.0 9.8 63.3%

    Class C Injury Crashes/Mile 27.2 19.6 -27.9%

    PDO Crashes/Mile 89.1 53.8 -39.6%

    Frontal Impact Crashes/Mile 25.4 25.3 -0.4%

    Rear End Crashes/Mile 80.3 40.0 -50.2%

    AADT 37,000 43,000 16.2%

    Intersection Density (/Mile) 3.7 3.3 n/a

    Length (Miles) 2.2 1.2 n/a

    Superstreet vs. Traditional Intersection Corridors

    34

  • Analysis procedure for RCUTs

    Six types of RCUTs

    Can extend logic to other geometries

    HCS implementation

    Turning movement translator

    Key is estimation of extra travel time

    Includes control delay at all points plus time

    spent traveling extra distance

    Proposed HCM 2015

    35

  • RTOR

    UTOR

    Critical headway

    Critical follow-up time

    Lane utilization

    U-turn saturation flow adjustment

    Arrival types

    Considering Unique RCUT Features

    36

  • 2013 NCDOT study

    Good ped options

    Bikes fine on main

    street

    Crossing bikes

    As peds

    As vehicles

    Proposed direct link

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