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Calibrating Model Speeds, Capacities, and Volume Delay Functions Using Local Data SE Florida FSUTMS Users Group Meeting February 6, 2009 Dean Lawrence Munn

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Calibrating Model Speeds, Capacities, and Volume Delay Functions Using Local Data SE Florida FSUTMS Users Group Meeting February 6, 2009 Dean Lawrence Munn. Typical Free-flow Speed Lookup Table. Typical Capacity Lookup Table. Reasons for Improving. - PowerPoint PPT Presentation

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Page 1: Calibrating Model Speeds, Capacities, and Volume Delay Functions Using Local Data

Calibrating Model Speeds, Capacities, and Volume Delay Functions Using

Local Data

SE Florida FSUTMS Users Group Meeting February 6, 2009

Dean Lawrence Munn

Page 2: Calibrating Model Speeds, Capacities, and Volume Delay Functions Using Local Data

Calibrating Model Speeds, Capacities and Volume Delay Functions Using Local DataFebruary 2009

Typical Free-flow Speed Lookup Table

Page 3: Calibrating Model Speeds, Capacities, and Volume Delay Functions Using Local Data

Calibrating Model Speeds, Capacities and Volume Delay Functions Using Local DataFebruary 2009

Typical Capacity Lookup Table

Page 4: Calibrating Model Speeds, Capacities, and Volume Delay Functions Using Local Data

Calibrating Model Speeds, Capacities and Volume Delay Functions Using Local DataFebruary 2009

Reasons for Improving

Model outputs are more realistic and detailedModel validation process and outcome

improvedModels are sensitive to more project typesModel applications are easier to defend

Page 5: Calibrating Model Speeds, Capacities, and Volume Delay Functions Using Local Data

Calibrating Model Speeds, Capacities and Volume Delay Functions Using Local DataFebruary 2009

Indiana Statewide Travel Demand Model Genesee County, Michigan Model Maricopa Association of Governments Model

Some Recent Projects:

Page 6: Calibrating Model Speeds, Capacities, and Volume Delay Functions Using Local Data

Calibrating Model Speeds, Capacities and Volume Delay Functions Using Local DataFebruary 2009

Indiana Statewide Travel Demand Model• Current model covers 87,000 sq miles• Model network has 45,000 links, but only covers Minor Collector or higher• TAZ system has 4700 zones• Extends into neighboring states, includes major metro areas• Contains detailed data

Page 7: Calibrating Model Speeds, Capacities, and Volume Delay Functions Using Local Data

Calibrating Model Speeds, Capacities and Volume Delay Functions Using Local DataFebruary 2009

Indiana Statewide Travel Demand Model

• Speed assumptions have evolved over time• Use real posted speed from roadway data files• Modify posted speed for advisory speeds (no passing, horiz. curves, etc.) • Modify posted speed using data gathered from actual travel speeds• Combine travel speed and intersection delay into composite travel time

Free-flow Speed Assumptions

Page 8: Calibrating Model Speeds, Capacities, and Volume Delay Functions Using Local Data

Calibrating Model Speeds, Capacities and Volume Delay Functions Using Local DataFebruary 2009

Table 1. Free-Flow Speed Estimation Formula

Area Type

Free-Flow Speed 1, 2 Condition Note

2-lane 2-way undivided highways

03397.30PSPD009751.0 2 25 PSPD 55 Rural 25 PSPD < 25

065483.98PSPD640917.117 PSPD001279.00015.0 25 PSPD 55 Suburban 25 PSPD < 25

PSPD9437.0189.6 25 PSPD 55 Urban 25 PSPD < 25

No or Partial Access Control

2-lane 2-way divided highways

12 019702.0)323105.72PSPD(000017.0

835323.19 25 PSPD 55 Rural

25 PSPD < 25 PSPD/803252.41857638.0 e105587.84PSPD180682.3 25 PSPD 55 Suburban

25 PSPD < 25

PSPD373821.0)PSPDln(023365.0119687.0 1 25 PSPD 55 Urban

25 PSPD < 25

No Access Control

Multilane undivided highways

12 019702.0)323105.72PSPD(000017.0

835323.19 25 PSPD 65 Rural

25 PSPD < 25 PSPD/803252.41857638.0 e105587.84PSPD180682.3 25 PSPD 55 Suburban

25 PSPD < 25

PSPD373821.0)PSPDln(023365.0119687.0 1 25 PSPD 55 Urban

25 PSPD < 25

Multilane divided highways 32 PSPD000744.0PSPD071256.0PSPD836165.2 25 PSPD 50

PSPD8223.00359.16 50 < PSPD 65 Rural

25 PSPD < 25

12 035258.0)166165.64PSPD(000071.0

)PSPDln(061039.9 25 PSPD 55 Suburban

25 PSPD < 25

1)PSPDln(016217.0081714.0 25 PSPD 55 Urban 25 PSPD < 25

No or Partial Access Control

Full access controlled highways 64.00 PSPD = 55 67.06 PSPD = 60 70.21 PSPD = 65

73.30 PSPD = 70

Note: 1 Free-flow speeds in mph, 2 PSPD: Posted speeds in mph Source: Bernardin, Lochmueller & Associates, Inc., 2004

Free-flow Speed

Developed for I-69 Tier 1 EIS Incorporated into ISTDM v 4 Takes estimated posted speeds Adjusts for actual driver behavior Data came from 26 county GPS speed survey This methodology has been implemented in multiple MPO models

Indiana Statewide Travel Demand Model

Page 9: Calibrating Model Speeds, Capacities, and Volume Delay Functions Using Local Data

Calibrating Model Speeds, Capacities and Volume Delay Functions Using Local DataFebruary 2009

PFC

g-10.5Cd

2

where, d = delay per vehicle,

g = effective green time, C = cycle length, and PF = progression adjustment factor.

Free-flow Speed

Intersection capability developed for I-69 Tier 1 EIS Incorporated into ISTDM v 4 Adjusts travel times to account for signal delays Method transferred to several MPO models Recent MPO models have enhanced capabilities

Accounting for Intersection Delay

Indiana Statewide Travel Demand Model

Page 10: Calibrating Model Speeds, Capacities, and Volume Delay Functions Using Local Data

Calibrating Model Speeds, Capacities and Volume Delay Functions Using Local DataFebruary 2009

Development of Model CapacitiesComputing an HCM compatible capacity from link attributesOriginally developed for the Indiana Statewide ModelApplied on a link by link basisDocumented in NCHRP 358 as a best practiceSubsequently implemented in many models

Variables Used:SpeedNumber of LanesFunctional ClassificationAccess ControlMedian TypeLane WidthShoulder WidthPct. Heavy VehiclesInterchange DensityAccess Points per Mile

Indiana Statewide Travel Demand Model

Page 11: Calibrating Model Speeds, Capacities, and Volume Delay Functions Using Local Data

Calibrating Model Speeds, Capacities and Volume Delay Functions Using Local DataFebruary 2009

Calibrating Model Capacities

bAFFSa

bFFSaf s

)ln(*

)ln(*

where, sf = capacity reduction factor for signal delay,

a, b = constants, FFS = free-flow speed, and AFFS = “adjusted” free-flow speed with signal delay.

Adjustment to Capacity for Signal Delay

Signal delay is accounted for in capacity instead of VDFCapacity reduction factor is a ratio of flow ratesSimilar effect as VDFs with signal delayAdvantage is simplicity at assignment stage

Indiana Statewide Travel Demand Model

Page 12: Calibrating Model Speeds, Capacities, and Volume Delay Functions Using Local Data

Calibrating Model Speeds, Capacities and Volume Delay Functions Using Local DataFebruary 2009

Calibrating Volume-Delay Functions

Original work done in 1996-97 at INDOTINDOT calibrated BPR alphas and betasINDOT ATR data covered multiple road classesINDOT had a handful of locations for each classBPR alpha and beta parameters were developed and coded as link attributes

Indiana Statewide Travel Demand Model

Page 13: Calibrating Model Speeds, Capacities, and Volume Delay Functions Using Local Data

Calibrating Model Speeds, Capacities and Volume Delay Functions Using Local DataFebruary 2009

Genesee County Michigan Model

• Current model covers 652 sq miles• Model network has 4300 links• TAZ system has 676 zones• Network contains detailed Michigan Geographic Framework data

Page 14: Calibrating Model Speeds, Capacities, and Volume Delay Functions Using Local Data

Calibrating Model Speeds, Capacities and Volume Delay Functions Using Local DataFebruary 2009

Free-flow Speed AssumptionsMore Advanced GPS Survey Applications Methodology developed for AMBAG model Used for Genesee Model Being applied for Phoenix Model

Genesee County Michigan Model

Page 15: Calibrating Model Speeds, Capacities, and Volume Delay Functions Using Local Data

Calibrating Model Speeds, Capacities and Volume Delay Functions Using Local DataFebruary 2009

End Time

Correspond Model Link

Model Link

Min Max

TL = Max - Min

TL

Start Time

T1Tn-1 Tn

= GPS Link Layer

= Model Node

TL = Total travel time between two nodes

TL = Tn - T1

T1…..Tn = GPS Time

= GPS Point

Free-flow Speed AssumptionsComputing Space-Mean Speed from GPS

Genesee County Michigan Model

Page 16: Calibrating Model Speeds, Capacities, and Volume Delay Functions Using Local Data

Calibrating Model Speeds, Capacities and Volume Delay Functions Using Local DataFebruary 2009

400 feet 400 feet

TL t1sd t2sd

tmb D

Mid Block

DL

= Signal node t1sd = Travel time Signal delay t2sd = Travel time Signal delay

tmb = Travel time mid-block without Signal delay DL = Total distance of the link between two Signals TL = Total travel time between two Signals

Free-flow Speed AssumptionsComputing Space-Mean Speed from GPS – Separating Signals and Mid-Block

Information is used to adjust mid-block free flow speed from posted speed Also used to add travel time for intersection delay Actual GPS data by corridor was used to verify accuracy of Speed-Cap program

Genesee County Michigan Model

Page 17: Calibrating Model Speeds, Capacities, and Volume Delay Functions Using Local Data

Calibrating Model Speeds, Capacities and Volume Delay Functions Using Local DataFebruary 2009

Maricopa Association of Governments Model

• Started major model update in 2008, activity based model• Current model covers 11,000 sq miles• Model network has 22,000 links, but only covers Minor Arterial or higher• TAZ system has 2000 zones• Dean was PM on supply-part modeling tasks (network)• Project is on-going

Page 18: Calibrating Model Speeds, Capacities, and Volume Delay Functions Using Local Data

Calibrating Model Speeds, Capacities and Volume Delay Functions Using Local DataFebruary 2009

Maricopa Association of Governments Model

• Obtain travel speeds from GPS survey covering ¾ of road network• Obtain travel speeds from loop detector data (~40 locations)• Test travel speeds from other ITS detectors (radar, passive acoustic)• Used the same methodology used for Genesee, Michigan• Final product was a new speed lookup table

Free-flow Speed Assumptions

Page 19: Calibrating Model Speeds, Capacities, and Volume Delay Functions Using Local Data

Calibrating Model Speeds, Capacities and Volume Delay Functions Using Local DataFebruary 2009

Calibrating Model Capacities

Freeways (facility type 1)

CBDOutlying

CBDMixed Urban Suburban Rural

1 2 3 4 5Speed 55 60 65 70 75

No. of Thru Lanes per Direction 4 3 3 3 2Lane Width 12 12 12 12 12

RH Shoulder Width 1 6 6 6 6Pct. Hvy. Veh. 0.22 0.22 0.22 0.32 0.32

1Hr Ideal Flow per Lane 2250 2300 2350 2400 2400f_lateral_clearance 0.98 1.00 1.00 1.00 1.00

f_heavy_vehicles 0.87 0.87 0.87 0.83 0.83f_lane_width 1.00 1.00 1.00 1.00 1.00

f_number_lanes 0.98 0.95 0.95 0.95 0.93f_interchange_density 0.85 0.90 0.95 1.00 1.001Hr Capacity per Lane 1,605 1,727 1,863 1,895 1,849

2.25 3Hr Capacity per Lane 3,611 3,887 4,192 4,264 4,1614.50 6Hr Capacity per Lane 7,222 7,774 8,384 8,528 8,322

10.00 24Hr Capacity per Lane 16,048 17,275 18,631 18,951 18,493

Variables

Capacity Adjustments

Using Typical Profiles

Maricopa Association of Governments Model

Page 20: Calibrating Model Speeds, Capacities, and Volume Delay Functions Using Local Data

Calibrating Model Speeds, Capacities and Volume Delay Functions Using Local DataFebruary 2009

Calibrating Model Capacities

Number of Lanes Adjustment Interchange Density Adjustment Lane Width AdjustmentLanes Adjustment Area Type Adjustment Width Adjustment

1 0.93 1 0.85 9 0.952 0.93 2 0.90 10 0.983 0.95 3 0.95 11 0.994 0.98 4 1.00 12 1.005 1.00 5 1.00

FHWA Functiona

l Class HV Prop Default Access Points Per MileRur Int 0.32 0.00Rur Princ Art 0.18 2.50Rur Min Art 0.12 5.00Rur Maj Col 0.10 7.50Rur Min Col 0.05 10.00Rur Local 0.07 10.00Urb Int 0.22 0.00Urb Exp 0.16 0.00Urb Art 0.09 15.00Urb Maj Col 0.07 10.00Urb Min Col 0.04 20.00Urb Local 0.07 20.00Ramp 0.22 0.00

Freeway - Capacity Adjustment Factor for Shoulder WidthNote: Reads number of lanes and speed from Freeway Sheet

1 2 3 4 52 0.95 1.00 1.00 1.00 1.003 0.96 1.00 1.00 1.00 1.004 0.98 1.00 1.00 1.00 1.005 0.99 1.00 1.00 1.00 1.00

Area TypeLanes

Freeway Ideal Capacity per Lane Per Hour

Ideal Flow0 60 2250

60 65 230065 70 235070 75 2400

Non-Freeway Ideal Capacity per Lane Per Hour

Ideal Flow0 50 1700

50 55 200055 60 210060 75 2200

Speed Range

Speed Range

Using Typical Profiles

Page 21: Calibrating Model Speeds, Capacities, and Volume Delay Functions Using Local Data

Calibrating Model Speeds, Capacities and Volume Delay Functions Using Local DataFebruary 2009

Calibrating Model CapacitiesThe Problem of Multi-Hour Time Periods

HCM only provides guidance for one hour capacitiesWith uniform temporal distribution, multiply by number of hoursReal traffic is not uniformly distributed over timePeriod-specific directional and peak factors have to be

developed

0.00%

0.50%

1.00%

1.50%

2.00%

2.50%

3.00%

3.50%

4.00%

4.50%

5.00%

0 5 10 15 20 25 30

Maricopa Association of Governments Model

Page 22: Calibrating Model Speeds, Capacities, and Volume Delay Functions Using Local Data

Calibrating Model Speeds, Capacities and Volume Delay Functions Using Local DataFebruary 2009

Calibrating Volume-Delay Functions

Phoenix project used extensive loop detector dataPhoenix data limited to freeways and a few arterials Phoenix data allowed some testing of variability by area type

Page 23: Calibrating Model Speeds, Capacities, and Volume Delay Functions Using Local Data

Calibrating Model Speeds, Capacities and Volume Delay Functions Using Local DataFebruary 2009

Calibrating Volume-Delay FunctionsFreeway Loop Detector Data

Page 24: Calibrating Model Speeds, Capacities, and Volume Delay Functions Using Local Data

Calibrating Model Speeds, Capacities and Volume Delay Functions Using Local DataFebruary 2009

Calibrating Volume-Delay FunctionsFreeway Loop Detector Data

Page 25: Calibrating Model Speeds, Capacities, and Volume Delay Functions Using Local Data

Calibrating Model Speeds, Capacities and Volume Delay Functions Using Local DataFebruary 2009

0

10

20

30

40

50

0 50 100 150 200Vol (veh/15min)

Sp

eed

(m

ph

)Lane 1 (left lane)

Lane 2 (shoulder lane)

Calibrating Volume-Delay FunctionsSignalized Arterial Loop Detector Data

Page 26: Calibrating Model Speeds, Capacities, and Volume Delay Functions Using Local Data

Calibrating Model Speeds, Capacities and Volume Delay Functions Using Local DataFebruary 2009

Sample Freeway Section

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60

V/C Ratio

Ob

serv

ed T

rave

l S

pee

d (

MP

H)

Actual

BPR

Spiess

HCM max density 45Freeflow Speed 61.3

Alpha Beta R-squared RMSEBPR 1.12 5.15 0.97 0.41Spiess 7.57 1.08 0.96 0.38

Calibrating Volume-Delay FunctionsCurve Parameter Calibration and Evaluation Process

Page 27: Calibrating Model Speeds, Capacities, and Volume Delay Functions Using Local Data

Calibrating Model Speeds, Capacities and Volume Delay Functions Using Local DataFebruary 2009

Thank You

Any Questions?