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    SIGNALISED INTERSECTIONS

    TS4273 Traffic Engineering

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    First Traffic Light

    Traffic lights were used before the advent of themotorcar. In 1868, British railroad signalengineer J P Knight invented the first traffic light,a lantern with red and green signals.

    It was installed at the intersection of George andBridge Streets in front of the British House of

    Commons to control the flow of horse buggiesand pedestrians.

    http://www.didyouknow.cd/trafficlights.htm

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    Prinsip-prinsip desain simpang

    bersinyal

    Suatu persimpangan membutuhkan lampu

    lalulintasjika waktu tunggu rata-rata

    kendaraan sudah lebih besar daripada waktu

    tunggu rata-rata kendaraan padapersimpangan dengan lampu lalulintas.

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    Prinsip-prinsip desain simpang

    bersinyal

    Waktu tunggu rata-rata kendaraan pada

    persimpangan bersinyal dipengaruhi oleh:

    Arus lalulintas pada masing-masing arah,

    Waktu antara kedatangan kendaraan dari

    masing-masing arah,

    Keberanian pengemudi untuk menerima waktu

    antara yang tersedia guna menyeberangi jalan.

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    Prinsip-prinsip desain simpang

    bersinyal

    Unsignalised Signalised

    Traffic Flow

    Delay

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    Scope of IHCM

    Signalised Intersection Analyses

    Isolated, fixed-time controlled signalised

    intersections with normal geometry layout (four-

    arm and three-arm) and traffic signal control

    devices. Coordinated traffic signal control is normally

    needed if the distance to adjacent signalised

    intersections is small (< 200m). Persimpangan Raya Darmo

    Polisi Istimewa

    & Raya Darmo RA Kartini.

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    Objectives of IHCM

    Signalised Intersection Analyses

    To avoid blockage of an intersection by

    conflicting traffic streams, thus

    guaranteeing that a certain capacity can

    be maintained even during peak trafficconditions;

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    Objectives of IHCM

    Signalised Intersection Analyses

    To facilitate the crossing of a major road

    by vehicles and/or pedestrians from a

    minor road;

    To reduce the number of traffic accidents

    caused by collisions between vehicles in

    conflicting directions.

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    Potential Conflict at Intersections

    DIVERGING

    MERGING

    DIVERGING

    MERGING

    CROSSING

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    Primary and Secondary Conflictis in a

    Four-Arm Signalised Intersections

    Primary Conflict

    Secondary Conflict

    Vehicle Stream

    Pedestrian Stream

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    Time Sequence

    for Two-Phase Signal Control

    Street A

    Street B

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    Time Sequence

    for Four-Phase Signal Control

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    Time Sequence

    for Two-Phase Signal ControlIntergreen A B

    A

    B

    Intergreen B A

    Green Time All Red B A

    Cycle Time

    Green Time

    All Red A B All Red A B

    Intergreen A B

    Street A

    Street B

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    Kendaraan masih boleh lewat

    pada saat lampu kuning menyala

    Kendaraan tidak boleh lewat

    pada saat lampu kuning menyala

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    Fase 1

    Fase 2

    Waktu antar hijau = 6 detik

    Fase 1

    Fase 2

    Waktu antar hijau = 4 detik

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    Purpose of the Intergreen Period

    Warn discharging traffic that the phase is

    terminated.Amber Period (for urban traffic

    signal in Indonesia is normally 3,0 sec)

    Certify that the last vehicle in the green phase

    which is being terminated receives adequate

    time to evacuate the conflict zone before the first

    advancing vehicle in the next phase enters the

    same area.All-Red Period

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    Signal Phasing Arrangements

    Introducing more than two phases

    normally leads to an increase of the

    cycle time and of the ratio of time

    allocated to switching between phases(especially for isolated and fixed-

    controlled).

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    Signal Phasing Arrangements

    Although this may be beneficial from the

    traffic safety point of view, it normally

    means that the overall capacity of the

    intersection is decreased.

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    Basic Model for Saturation Flow (Akcelik 1989)

    Time

    RateofDischargeofQueuein

    aFullySatu

    ratedGreenPeriod

    Effective Green Time

    Saturation Flow

    Actual

    Flow

    Curve

    Start Loss End Gain

    Display Green TimeIntergreen

    Effective

    FlowCurve

    Fi (Starting Phase Change Time)

    Fk (Terminating Phase Change Time)

    Amber All-Red

    Phases for the

    Movement

    Phases for the

    Conflicting

    Movement

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    Basic Model Saturation Flow

    Discharge rate starts from 0 at the beginning ofgreen and reaches its peak value after 10-15sec

    Effective Green = Displayed Green Time StartLoss + End Gain

    Start loss End gain 4,8 sec (MKJI p.2-12)

    Effective Green = Displayed Green Time

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    Basic Model Saturation Flow

    Base saturation flow is different between

    Protected approach and Opposed approach

    For protected approach S0 = 600 x We

    For opposed approach S0 in Indonesia

    usually lower where there is a high ratio ofright turning movements, compare with

    Western models.

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    Perhitungan Arus Jenuh

    Metode Time Slice

    Arus jenuh/jam (3.600/5)x4,5 = 3.240 smp/jam

    Jika lebar lajur = 4,0m (3.240/4) = 810 smp/jam/m

    Maka S = 810 x We

    LV HV MC M LV HV MC M

    0.0 - 5.0 1 0 3 4 1.0 0.0 1.2 2.2

    5.1 - 10.0 1 0 4 5 1.0 0.0 1.6 2.6

    10.1 - 15.0 2 1 3 6 2.0 1.3 1.2 4.5

    15.1 - 20.0 2 1 1 4 2.0 1.3 0.4 3.7

    20.1 - 25.0 2 1 2 5 2.0 1.3 0.8 4.1

    25.1 - 30.0 2 0 1 3 2.0 0.0 0.4 2.4

    30.1 - 35.0 2 0 0 2 2.0 0.0 0.0 2.0

    35.1 - 40.0 1 0 0 1 1.0 0.0 0.0 1.0

    Total 30 Max 4.5

    Time PeriodTraffic Flow (veh) Traffic Flow (veh)

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    Traffic Safety Considerations

    Traffic accident rate for signalised

    intersections has been estimated as

    0,43 accidents/million incoming

    vehicles as compare to 0,60 forunsignalised intersections and 0,30 for

    roundabouts.

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    STEP A-1: Geometric, Traffic Control

    and Environmental Conditions

    General information (date, handled by, city, etc.)

    City size (to the nearest 0,1 M inhabitants)

    Signal phasing & timing

    Left turn on red (LTOR) Approach code

    Road environment and level of side friction

    Median

    Gradient

    Approach width (to the nearest tenth of a meter)

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    Geometry of Signalised Intersection

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    STEP A-2: Traffic Flow Conditions

    Vehicle Type

    pce for Approach Type

    Protected Opposed

    Light Vehicle (LV) 1,0 1,0

    Heavy Vehicle (HV) 1,3 1,3

    Motorcycle (MC) 0,2 0,4

    Q = QLV + (QHV x pceHV) + (QMC x pceMC)

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    STEP B-1: Signal Phasing and

    Timing

    If the number and types of signal phases

    are not known, two-phase control should

    be used as a base case.

    Separate control of right-turning

    movements should normally only be

    considered if a turning-movement exceeds

    200 pcu/h and has a separate lane.

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    STEP B-1: Signal Phasing and

    Timing

    Early start = leading green one approach is

    given a short period before the start of the green

    also in the opposing direction (usually 25%-33%

    from total green time) Late cut-off = lagging green the green light in

    one approach is extended a short period after

    the end of green in the opposing direction.

    The length of the leading and the lagging green

    should not be shorter than 10 sec.

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    STEP B-2:

    Intergreen time and lost time

    Intersection

    Size

    Mean Road

    Width

    Intergreen Time

    Default Values

    Small 6 9 m 4 sec/phase

    Medium 10 14 m 5 sec/phase

    Large 15 m 6 sec/phase

    Only for planning purposes !!!

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    STEP B-2:

    Intergreen time and lost time

    LEV, LAV distance from stop line to conflict

    point for evacuating and advancing vehicle (m)

    lEV length of evacuating vehicle (m) VEV, VAV speed of evacuating and advancing

    vehicle (m/sec)

    AV

    AV

    EV

    EVEVi

    V

    L

    V

    lLALLRED max

    For operational and design analysis !!!

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    AV

    EV

    LAV

    LAV

    LEV

    lEV

    CRITICAL CONFLICT

    POINT

    AV

    AV

    EV

    EVEVi

    V

    L

    V

    lLALLRED max

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    STEP B-2:

    Intergreen time and lost time

    VAV 10m/sec (motor vehicles)

    VEV 10m/sec (motor vehicles)

    VEV 3m/sec (un-motorised)

    VEV 1,2m/sec (pedestrians)

    lEV 5m (LV or HV)

    lEV 2m (MC or UM)

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    STEP B-2:

    Intergreen time and lost time

    IG Intergreen = Allred + Amber

    The length ofAMBER usually 3,0 sec

    ii IGAMBERALLREDLTI

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    PROTECTED (P)Discharge without any

    conflict between right-

    turning movements andstraight-through/left-

    turning movements.

    STEP C-1: Approach Type Street A

    Street B

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    OPPOSED (O) Discharge with conflictbetween right-turning movements and straight-

    through/left-turning movements from different

    approaches with green in the same phase.

    Street A

    Street B

    STEP C-1: Approach Type

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    STEP C-2:

    Effective Aproach Width (We)

    Without LTOR

    For Approach Type P (Q = QST)

    If WEXIT We x (1 - pRT - pLT)

    We = WEXIT

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    W

    A

    WLTOR

    WEN

    TRY

    WEXIT

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    STEP C-2:

    Effective Aproach Width (We)

    If WLTOR 2m (it is assumed that the LTOR

    vehicle can bypass the other vehicle)

    We = min { (WA-WLTOR) , (WENTRY) }

    For Approach Type P (Q = QST)

    If WEXIT < We x (1 pRT)

    We = WEXIT

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    If WLTOR < 2m (it is assumed that the LTOR

    vehicle cannot bypass the other vehicle)

    We = min { (WA) , (WENTRY+WLTOR) ,

    (Wax(1+pLTOR)-WLTOR)}

    For Approach Type P (Q = QST)

    If WEXIT < We x (1 pRT pLTOR)We = WEXIT

    STEP C-2:

    Effective Aproach Width (We)

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    STEP C-3: Base Saturation Flow (S)

    For protected approach

    no FFSS ...1

    eo WS 600

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    For Approach Type P

    S0 base saturation flow (pcu/hg)

    We effective width (m)

    Figure C-3:1 page 2-49

    eWS 6000

    STEP C-3: Base Saturation Flow (S)

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    For Approach Type O (opposed)

    QRT and QRTO (Column 14 Form SIG-II opposed

    discharge right-turning)

    Figure C-3:2 page 2-51 for approaches withoutseparate right-turning.

    Figure C-3:3 page 2-52 for approaches with

    separate right-turning.

    Use interpolation if approach width larger or

    smaller than actual We

    STEP C-3: Base Saturation Flow (S)

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    Ex: without separate right-turning lane

    QRT = 125 pcu/h, QRTO = 100 pcu/h

    Actual We = 5,4m

    Obtain from Figure C-3:2 p. 2-51 (We=5 & We=6)S6,0 = 3.000 (pcu/hg) ; S5,0 = 2.440 (pcu/hg)

    Calculate;

    S5,4 =(5,4-5,0)x(S6,0 - S5,0)+ S5,0

    =0,4(3.000-2.440)+2.440 2.660 (pcu/hg)

    STEP C-3: Base Saturation Flow (S)

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    If right-turning movement > 250 pcu/h, protected

    signal phasing should be considered

    For No Separate RT-lane

    If QRTO < 250 pcu/h Determine SPROV for QRTO = 250 pcu/h

    Determine Actual S as

    S = SPROV [(QRTO - 250) x 8]pcu/h

    STEP C-3: Base Saturation Flow (S)

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    For No Separate RT-lane

    If QRTO > 250 pcu/h

    Determine SPROV for QRTO and QRT= 250 pcu/h

    Determine Actual S as

    S = SPROV [(QRTO + QRT - 500) x 2]pcu/h

    If QRTO < 250 pcu/h and QRT > 250 pcu/h Determine S as for QRT = 250 pcu/h

    STEP C-3: Base Saturation Flow (S)

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    For Separate RT-lane

    If QRTO > 250 pcu/h

    QRT < 250 pcu/h Determine S from Figure C3:3

    through extrapolation QRT > 250 pcu/h Determine SPROV as for QRTO

    and QRT= 250 pcu/h

    If QRTO < 250 pcu/h and QRT > 250 pcu/h Determine S from Figure C3:3 through

    extrapolation

    STEP C-3: Base Saturation Flow (S)

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    STEP C-4: City Size Adjustment

    Factor FCS [ Table C-4:3 p.2-53]

    City Size Inhab. (M) FCS

    Very Small 0,1 0,82

    Small > 0,1 - 0,5 0,88

    Medium > 0,5 - 1,0 0,94

    Large > 1,0 - 3,0 1,00

    Very Large > 3,0 1,05

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    STEP C-4: Side Friction Adjustment

    Factor FSF [ Table C-4:4 p.2-53]

    0.70

    0.75

    0.80

    0.85

    0.90

    0.95

    1.00

    0.00 0.05 0.10 0.15 0.20 0.25

    pUM

    Fsf

    CHO CHP CMO CMP CLO CLP

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    STEP C-4: Side Friction Adjustment

    Factor FSF [ Table C-4:4 p.2-53]

    0.70

    0.75

    0.80

    0.85

    0.90

    0.95

    1.00

    0.00 0.05 0.10 0.15 0.20 0.25

    pUM

    Fsf

    RHO RHP RMO RMP RLO RLP

    STEP C 4 Sid F i i Adj

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    STEP C-4: Side Friction Adjustment

    Factor FSF [ Table C-4:4 p.2-53]

    0.70

    0.75

    0.80

    0.85

    0.90

    0.95

    1.00

    1.05

    0.00 0.05 0.10 0.15 0.20 0.25

    pUM

    Fsf

    RAO RAP

    STEP C 4 G di t Adj t t

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    STEP C-4:Gradient Adjustments

    Factors FG [Figure C-4:1 p.2-54]

    0.90

    0.91

    0.92

    0.93

    0.94

    0.95

    0.96

    0.97

    0.98

    0.99

    1.00

    1.01

    1.02

    1.03

    1.04

    1.05

    -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10

    Gradient (%)

    GradientFactorFg

    If G 0 1 (0,01 x G)

    If G < 0 1 (0,005 x G)

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    LP distance between stop-line

    and first parked vehicle (m)

    WAWidth of the approach (m)

    g Green time in the approach (default value 26 sec)

    It should not be applied in cases were the effective widthis determined by the exit width.

    gWgL

    WL

    F AP

    AP

    P //3

    23

    STEP C-4: Effect of Parking Adjustments

    Factors FP [Figure C-4:2 p.2-54

    STEP C 4 Ri ht T Adj t t

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    STEP C-4: Right Turn Adjustments

    Factors FRT

    1.000

    1.050

    1.100

    1.150

    1.200

    1.250

    1.300

    0.000 0.100 0.200 0.300 0.400 0.500 0.600 0.700 0.800 0.900 1.000

    pRT

    Frt

    FRT = 1.0 + pRT x 0.26

    STEP C 4 L ft T Adj t t

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    STEP C-4: Left Turn Adjustments

    Factors FLT

    0.800

    0.850

    0.900

    0.950

    1.000

    0.000 0.100 0.200 0.300 0.400 0.500 0.600 0.700 0.800 0.900 1.000

    pLT

    Flt

    FLT = 1.0 - pLT x 0.16

    C l l t d th dj t d l

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    Calculated the adjusted value

    of saturation flow S

    SO Base saturation flow

    FCS City size FSF Side friction

    FG Gradient

    FP Parking

    FRT Right turn

    FLT Left turn

    hgpcuFFFFFFSS LTRTPGSFCSO /

    STEP C 5 Fl /S t ti Fl

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    STEP C-5: Flow/Saturation Flow

    Ratio

    Calculate the Flow Ratio (FR) for each approach

    Calculate the Intersection Flow Ratio (IFR)

    Calculate the Phase Ratio (PR) for each phase

    SQFR /

    CRITFRIFR

    IFRFRPR CRIT /

    Sum of the critical (highest) flow ratios for

    all consecutive signal phases in a cycle

    STEP C 6 C l Ti d G

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    STEP C-6: Cycle Time and Green

    Time

    Unadjusted cycle time (Cua)

    Green time (g)

    Adjusted cycle time (c)

    IFRLTIcua 1/55,1

    iuai PRLTIcg

    LTIgc

    LTI = S off all intergreen periods

    green times < 10 sec

    should be avoided !!!

    2 phase 40-80 sec

    3 phase 50-100 sec

    4 phase 80-130 sec

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    STEP D-1: Capacity

    Calculate the capacity of each approach

    Calculate the Degree of Saturation

    cgSC /

    CQDS / Acceptable valuenormally 0,75 !!!If the signal timing has been correctly

    done, DS will be nearly the same in all

    critical approaches !!!

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    STEP D-2: Need For Revisions

    Increase of approach width (especially for the

    approaches with the highest critical FR value)

    Changed signal phasing (i.e. separate phase forright-turning traffic)

    Prohibition of right turning movements willnormally increase capacity (i.e. reduction of the

    phase required).

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    STEP E-1: Preparations

    Fill in the information required in the

    head of Form SIG-V

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    STEP E-2: Queue Length

    For DS > 0,5

    NQ1 number of pcu that remain from the previousgreen phase

    DS degree of saturation = Q/C

    GR green ratio

    C capacity (pcu/h) = saturation flow x green ratio

    For DS 0,5

    C

    DSDSDSCNQ

    5,081125,0

    2

    1

    01 NQ

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    STEP E-2: Queue Length

    NQ2 number of queuing pcu that arrive during

    the red phase

    GR green ratio = g/c

    g green time (sec)

    c cycle time (sec) DS degree of saturation = Q/C

    Q traffic flow (pcu/h)

    360011

    2

    Q

    DSGR

    GRcNQ

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    STEP E-2: Queue Length

    QL Queue length (m)

    NQMAX adjust NQ with desired probability for

    overloading [for planning and design 5%, for

    operation 5-10%] figure E-2:2 p.2-66 20 average area occupied per pcu (20 sqm)

    WENTRY entry width (m)

    ENTRY

    MAX

    W

    NQQL

    2021 NQNQNQ

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    STEP E-3: Stopped Vehicle

    NS stop rate

    NQ total number of queuing vehicle

    Q traffic flow (pcu/h)

    c cycle time (sec)

    36009,0

    cQ

    NQNS

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    STEP E-3: Stopped Vehicle

    NSV number of stopped vehicles

    Q traffic flow (pcu/h)

    NS stop rate

    NSQNSV

    TOTAL

    SVTOTAL

    QNNS

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    STEP E-4: Delay

    A

    GR green ratio

    DS degree of saturation = Q/C

    DSGR

    GRA

    1

    15,02

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    STEP E-4: Delay

    DT mean traffic delay (sec/pcu)

    c cycle time (sec)

    NQ1 number of pcu that remain from the

    previous green phase

    C capacity (pcu/h)

    CNQAcDT 36001

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    STEP E-4: Delay

    DGj mean geometric delay for approach j

    (sec/pcu) pSV proportion of stopped vehicles in the

    approach = MIN (NS, 1)

    pT

    proportion of turning vehicles in theapproach

    Geometric Delay for LTOR = 6 sec [p.2-69]

    461 xpppDG SVTSVj

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    STEP E-4: Delay

    DI average delay for the whole intersection

    Average delay can be used as an indicator of

    the Level of Service (LOS) of each individualapproach as well as of the intersection as a

    whole.

    pcuQ

    DQD

    TOTAL

    j

    I sec/

    Indeks Tingkat Pelayanan (ITP) Lalulintas

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    Indeks Tingkat Pelayanan (ITP) Lalulintas

    Di Persimpangan Dengan Lampu Lalulintas

    Indeks Tingkat Pelayanan

    (ITP)Tundaan per kendaraan

    (detik)

    A 5.0

    B 5.1 15.0

    C 15.1 25.0

    D 25.1 40.0

    E 40.1 60.0

    F > 60.0

    Sumber: Perencanaan & Pemodelan Transportasi, Tamin, 2000

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    kapasitas Simpang Bersinyal

    Pelebaran lengan pendekat

    Kapasitas tergantung pada arus jenuh yang

    melewati garis henti (lebar lengan pendekat).

    Melebarkan lengan pendekat meningkatkankapasitas persimpangan.

    Panjang dari pelebaran lengan pendekat juga

    sangat penting untuk diperhatikan.

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    kapasitas Simpang Bersinyal

    Menaikkan waktu siklus

    semakin lama waktu siklus semakin besar

    kapasitas persimpangan semakin tinggi

    antrian dan tundaan yang terjadiMenurut MKJI 1997 [p.2-60] kisaran waktu siklus

    adalah 40 s/d 130 detik

    Pada kondisi tertentu terpaksa digunakan

    waktu siklus > 130 detik.

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    kapasitas Simpang Bersinyal

    Perubahan pola fasePerlu dilakukan simulasi untuk mendapatkanpola fase yang paling efisien.

    Semakin sedikit fase semakin tinggi kapasitas

    persimpangan semakin besar kemungkinankonflik yang dapat terjadi.

    Umumnya jumlah fase yang digunakan berkisarantara 2 s/d 4.

    Siklus dengan 2 fase umumnya dilengkapidengan early cut-offatau late-start.persimpangan Raya Darmo Polisi Istimewa

    Cara-cara untuk meningkatkan

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    kapasitas Simpang Bersinyal

    Meminimalkan waktu antar-hijau

    Waktu antar-hijau diperlukan untuk menjamin

    keamanan kendaraan yang melewati simpang

    pada saat detik akhir hijau, agar tidak tertabrakkendaraan yang mendapatkan fase hijau

    berikutnya.

    Meminimalkan waktu hijau mendekatkan

    garis henti dengan pusat persimpangan.

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    kapasitas Simpang Bersinyal

    Larangan belok kanan

    Meningkatkan kapasitas akibat pengurangan

    fase.

    Namun harus dilakukan manajemen lalulintasuntuk melayani kendaraan yang hendak belok

    kanan dengan menyediakan U-turn atau Re-

    routing.

    Prinsip-prinsip desain simpang

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    secara umum di Indonesia

    Jari-jari tikungan berkisar antara 6 s/d 9 meter

    Hindari jari-jari terlalu kecil kendala manuver

    bagi bus & truk

    Fasilitas penyeberang jalan (zebra cross) 2,5s/d 5 meter sejarak 2 meter didepan garis henti

    Panjang pelebaran harus lebih besar dari

    probabilitas panjang antrian terbesar

    Prinsip-prinsip desain simpang

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    secara umum di Indonesia

    Jalur khusus bus berakhir pada awal panjangantrian terbesar

    Jika arus lalulintas belok kanan cukup besar,perlu dibuatkan jalur khusus belok kanan

    dilengkapi dengan rambu dan marka yang

    sesuai