delay presentation

72
Analysis of Signalized Intersections

Upload: draggondeer

Post on 09-Nov-2015

226 views

Category:

Documents


0 download

DESCRIPTION

Presentation about Delay

TRANSCRIPT

  • Analysis of Signalized Intersections

  • 2

    What is Intersection analysis

    Inverse application of the signal timing design In signal timing design, green times

    are estimated to provide necessary capacity

    In intersection analysis, signal timing is known and used to estimate the existing capacity

  • Two methods

    Critical Movement Approach Apply adjustment factors to the

    demand volume

    HCM Methodology Saturation flow rates are reduced to

    reflect non-ideal prevailing conditions

    3

  • 4

    Steps for Critical Movement Approach

    1. Identify the lane geometry and use 2. Identify hourly demand volumes 3. Specify the signal timing 4. Convert demand volumes to equivalent passenger-car

    Volumes 5. Convert passenger-car equivalents to through-car

    equivalents 6. Convert Through-car equivalents under prevailing

    conditions to though-car equivalents under ideal conditions 7. Assign lane flow rates 8. Find critical-lane flows 9. Determine capacity and v/c ratios 10. Determine delay and level of service

  • 5

    1. Proportion of heavy vehicles 2. Proportion of local buses 3. Lane widths 4. Approach grade 5. Parking conditions on approach 6. Pedestrian interference levels

    Identify hourly demand volumes

  • 6

    1. Proportion of heavy vehicles 2. Proportion of local buses 3. Lane widths 4. Approach grade 5. Parking conditions on approach 6. Pedestrian interference levels

    Identify hourly demand volumes

  • Identify signal timings

    7

    1 2g G y ar l l= + + Effective green time Actual green time Actual yellow time Actual all-red time Start-up lost time Clearance lost time

    gGy

    ar1l2l

  • Convert Demand Volume to Equivalent Passenger Car Volume

    8

    (1 )pc HV HV LB LB HV LBV VP E VP E V P P= + +

  • Passenger-car Equivalents for Local Buses (Stop in Travel Lane)

    9

  • Passenger-car Equivalents for Local Buses (Stop in Parking Lane)

    10

  • Convert Passenger-Car Equivalent to Through-Car Equivalent

    11

    Left Turn Vehicles Protected left turns = 1.05 Permitted depends on opposing flow and

    number of opposing lanes Right Turn Vehicles Depends on the pedestrian volume in

    conflicting crosswalk

  • Through Car Equivalent for Left-Turning Vehicles

    12

  • Through Car Equivalent for Right-Turning Vehicles

    13

  • Though-car equivalents under ideal conditions

    14

    * * * *tcu

    w g p LU

    VvPHF f f f f

    =

    Adjustment factor for: Lane width Grade Parking Lane utilization

  • Lane Width Adjustment

    15

  • Grade Adjustment

    16

  • Parking Adjustment

    17

  • Lane Utilization Adjustment

    18

  • Assign Lane Flow Rates

    19

    Where a separate LT lane exist, assign all LT tcus to this lane group. If more than one lane exists, divide the tcu/h equally among the lanes

    Where a separate RT lane exist, assign all RT tcus to this lane group. If more than one lane exists, divide the tcu/h equally among the lanes

    For all mixed lane group(LT/TH/RH, LT/TH, TH/RT)divide the total tcu/h equally among all lanes, except that all LT tcus must be in the LH lane and all RT tcus in RH lane

  • Find Critical Lane Flow Rates for Each Signal Phase

    20

    From A1 to A3 Ring 1 148+420=568 Ring 2 203+330=533

    Maximum = 568

    From B1 to B3 Ring 1 120+380=500 Ring 2 220+250=570

    Maximum = 570 1138

  • Capacity and v/c Ratio

    21

    From A1 to A3 Ring 1 148+420=568 Ring 2 203+330=533

    Maximum = 568

    From B1 to B3 Ring 1 120+380=500 Ring 2 220+250=570

    Maximum = 570 1138

    1900( / )i ic g C=

    11900( / )

    n

    SUM ii

    c g C=

    = /i i iX v c=

    1/

    n

    c i ii

    X v c=

    =

  • Delay and Level of Service

    22

    1 2*i i id d PF d= +Approach delay for lane group i Uniform delay for lane group I Overflow plus random delay for lane group i Progression adjustment factor

    id1id2id

    PF

  • Uniform Delay and Overflow delay

    23

    2

    10.5 [1 ( / )]

    1 [min(1, )*( / )]i

    ii i

    C g CdX g C

    =

    22

    16225[( 1) ( 1) ]ii i ii i

    Xd X Xc N

    = + +

    Uniform Delay:

    Overflow Delay:

  • Progression Factor

    24

  • Level of Service

    25

  • Example

    26

  • Step 1 and 2: Geometry and volume

    27

  • Step 3:Signal Phase

    28

  • Step 4: Conversions to Equivalent Passenger Car Flow

    29

    EB Through movement 1100 veh/h, 10% heavy vehicle and 20 buses/hour Heavy=1100*10%*2.0=220 Bus=20*3.1=62 Passenger_car=1100*(1-10%)-20=970 Total=Heavy+Bus+Passenger_car=1252

  • Step 4: Conversions to Through-Car Equivalent

    30

    EB left turn Protected, equivalent=1.05

    NB left turn One-way street, No conflicting through Go through pedestrian crosswalk Pedestrian volume 100 ped/h Treated like right turn, equivalent=1.21

  • Step 5: Conversions to Equivalent Under Ideal Condition

    31

    No parking, fp=1.0 EB lane width is 11 feet, fw=0.97 EB Through has two lanes f=0.952

  • Step 6: Assign Flow to Lanes

    33

    WB approach 183 tch/h for right turn and 1242 for

    through Total 1424 uniformly split between two

    lanes Leftmost lane 712 through only Rightmost lane carries 183 right turn and

    1241-712=529 through

  • Step 6: Assign Flow to Lanes

    34

  • Step 7: Critical Volume

    35

  • Step 8: Capacity and v/c ratio

    36

  • Step 8: Capacity and v/c ratio

    37

  • Step 9: Delay and LOS

    38

    Uniform Delay:

  • Step 9: Delay and LOS

    39

    Overflow Delay:

  • Step 9: Delay and LOS

    40

    Total Delay = d1*PF+d2:

  • 41

    Steps for HCM Approach

    1. Input data

    2. Define movement groups and adjusted flow rate

    3. compute lane group flow rate

    4. input or compute phase duration

    5. Compute capacity

    6. Compute delays and LOS

  • 42

  • 43

    Step 2: Movement and lane groups

  • 44

    Step 3: Estimating the Saturation Flow

    Adjustment factors include: Lane width Heavy vehicles Grade Parking Local bus blockage Area type Pedestrian/bicycle interference

    0 w HV g p bb a LU RT LT Rpb Lpbs s Nf f f f f f f f f f f=

  • 45

    Adjustment for Lane Width

    Lanes width less than 10 ft Lane width between 10 and 12.9 ft Lane width larger than 12.9 ft

    0.96wf =

    1.0wf =

    1.04wf =

  • 46

    Adjustment for Heavy Vehicles

    Lanes width less than 10 ft Lane width between 10 and 12.9 ft Lane width larger than 12.9 ft

    0.96wf =

    1.0wf =

    1.04wf =

  • 47

    Adjustment for Grade

    1 / 200gf G=

    G Grade in %

  • 48

    Adjustment for Parking

    180.9 ( )3600

    mNP = ( 1)pN Pf

    N +

    =

    180.1 ( )3600 0.05

    m

    p

    NNf

    N

    =

  • 49

    Adjustment for Local Bus Blockage

    14.41.0 ( )3600

    BNB = ( 1)bbN Bf

    N +

    =

    14.4( )3600 0.05

    B

    p

    NNf

    N

    =

  • 50

    Adjustment for Type of Area

    0.9af =CBD location:

    Other location: 1.0af =

  • 51

    Adjustment for Lane Utilization

    1

    gLU

    g

    vf

    v N=

    Demand flow rate for the lane group gv

    1gv Demand flow rate for highest lane volume N Number of lanes in the lane group

  • 52

    Adjustment for Protected Turns

    0.85RTf = For exclusive RT lane

    0.95LTf = For protected LT lane

  • 53

    Adjustment for Pedestrian and Bicycle Interference with Turns

    Estimate Pedestrian Flow Rate During Green Phase Estimate the Average Pedestrian Occupancy in the Conflict

    Zone Estimate the Bicycle Flow Rate During the Green Phase Estimate the Average Bicycle Occupancy in the Conflict

    Zone Estimate the Conflict Zone Occupancy Estimate the Unblocked Portion of the Phase Determine Adjustment Factors

  • 54

    Step 4: Determine Lane Group Capacities and v/c Ratios

    Capacity of a lane group

    v/c ratio of a lane group

    Critical v/c ratio for intersection

    ( / )i i ic s g C=

    ( / )( / )

    i ii

    i i

    v v sXc g C

    = =

    maxmin

    max

    ( / ) *( )iC c

    i

    CX v sC L

    =

  • 55

    Step 5: Critical Lane Group Identification

  • 56

    Step 6: Estimate Delay and LOS

    Uniform Delay

    Incremental Delay

    Additional Delay Per Vehicle Due to Queue

    1 2 3d d d d= + +

    1d

    2d

    3d

  • 57

    Step 6: Estimate Delay and LOS

    2

    10.5 [1 ( / )]

    1 [min(1, )*( / )]C g Cd

    X g C

    =

    22

    8900 [( 1) ( 1) ( )]kIXd T X XcT

    = + + +

    2 2 2

    33600 ( )

    2 2 2b e eo e eo bQ Q Q Q Q Qd t

    vT c c+

    = +

  • 58

    Step 6: Aggregate Delay

    i ii

    Ai

    i

    d vd

    v=

    A AA

    IA

    i

    d vd

    v=

  • 59

    Step 7: Interpret the Results

    v/c ratios X for every lane group Critical v/c ratio X for the intersection Delays and LOS for each lane group Delays and LOS for each approach Delays for overall intersection

  • 60

    Step 7: Interpret the Results

    Scenario I: Xc1.0, change of phase plan, cycle length, or physical design is needed

  • 61

    Example

  • 62

    Volume Adjustment

  • 63

    Saturation Flow Rate Estimation

  • Saturation Flow Adjustment

    64

  • Saturation Flow Adjustment

    65

  • Saturation Flow Adjustment

    66

  • Saturation Flow Adjustment

    67

  • Saturation Flow Adjustment

    68

  • Capacity Analysis

    69

  • Delay and LOS

    70

  • What is the result if applying HCM to the former Critical Movement analysis example?

    71

  • 72

    1What is Intersection analysisTwo methodsSteps for Critical Movement Approach 5 6Identify signal timingsConvert Demand Volume to Equivalent Passenger Car VolumePassenger-car Equivalents for Local Buses (Stop in Travel Lane)Passenger-car Equivalents for Local Buses (Stop in Parking Lane)Convert Passenger-Car Equivalent to Through-Car EquivalentThrough Car Equivalent for Left-Turning VehiclesThrough Car Equivalent for Right-Turning VehiclesThough-car equivalents under ideal conditionsLane Width AdjustmentGrade AdjustmentParking AdjustmentLane Utilization AdjustmentAssign Lane Flow RatesFind Critical Lane Flow Rates for Each Signal PhaseCapacity and v/c RatioDelay and Level of ServiceUniform Delay and Overflow delayProgression FactorLevel of ServiceExampleStep 1 and 2: Geometry and volumeStep 3:Signal PhaseStep 4: Conversions to Equivalent Passenger Car FlowStep 4: Conversions to Through-Car EquivalentStep 5: Conversions to Equivalent Under Ideal Condition 32Step 6: Assign Flow to LanesStep 6: Assign Flow to LanesStep 7: Critical VolumeStep 8: Capacity and v/c ratioStep 8: Capacity and v/c ratioStep 9: Delay and LOSStep 9: Delay and LOSStep 9: Delay and LOSSteps for HCM Approach 42Step 2: Movement and lane groupsStep 3: Estimating the Saturation FlowAdjustment for Lane WidthAdjustment for Heavy VehiclesAdjustment for GradeAdjustment for ParkingAdjustment for Local Bus BlockageAdjustment for Type of AreaAdjustment for Lane UtilizationAdjustment for Protected TurnsAdjustment for Pedestrian and Bicycle Interference with TurnsStep 4: Determine Lane Group Capacities and v/c RatiosStep 5: Critical Lane Group IdentificationStep 6: Estimate Delay and LOSStep 6: Estimate Delay and LOSStep 6: Aggregate DelayStep 7: Interpret the ResultsStep 7: Interpret the ResultsExampleVolume AdjustmentSaturation Flow Rate EstimationSaturation Flow AdjustmentSaturation Flow AdjustmentSaturation Flow AdjustmentSaturation Flow AdjustmentSaturation Flow AdjustmentCapacity AnalysisDelay and LOS 71 72