The Fresno COG Travel Demand Forecasting Model How the Pieces Fit Together

Transcription

1 The Fresno COG Travel Demand Forecasting Model How the Pieces Fit Together Mike Bitner PE, Senior Transportation Planner Council of Fresno County Governments 1

2 COG Modeling Staff Mike Bitner Kathy Chung Kristine Cai Lindsey Monge 2

3 What is Ahead 3

4 Gain a basic understanding of travel demand forecasting. Understand model Input & assumptions Recognize model steps Appreciate model limitations Use Model output What s s Ahead (Objective) 4

5 Types of Models n Fashion Models n Trend Analysis (Growth( Factor Growth Factor) 3.5% annual growth on road n Simulation Individual vehicle movements n Travel Demand Model Fresno COG Model 5

6 What is a Travel Demand Model? A systematic process for translating land use and transportation supply into projections of future travel demand. Travel Demand Models estimate the amount of travel on the transportation system. 6

7 Planning Tool! Not Perfect 7

8 Model Users n Cities n County n Caltrans n Private Consultants n Developers n COG 8

9 Use of the Model n n n n n Analyzing General Plans Traffic Impacts of Development Corridor Studies Evaluating Traffic Mitigation Measures Evaluating Emissions Impacts for Transportation Conformity 9

10 Putting the Puzzle n Network n Traffic Analysis Zone n Land Use Together n 4 Step Modeling Process Trip Generation Trip Distribution Mode Split Traffic Assignment 10

11 Putting the Puzzle n Network Together 11

12 Transportation Network n Network Based on adopted general plans Replicates freeways, expressways, arterials and collectors existing & future Local roads not generally modeled 12

13 Network Development Network Development Using County GIS Street File 13

14 Links and Link Attributes n Nodes n Name n Distance n Facility Type n Lanes n Speed n Project ID n Improvement Year 14

15 Nodes n May represent intersections or other decision points n Nodes are described by coordinates for location purposes 15

16 Putting the Puzzle Together n Network n Traffic Analysis Zone 16

17 Urban Traffic Zones The basic geographical unit for distributing population and Employment within a study area. 17

18 Rural Traffic Analysis Zones 18

19 Traffic Analysis Zones Zone Data Households Single & multiple family Employment Retail Service Government Education Other 19

20 Putting the Puzzle Together n Network n Traffic Analysis Zone n Land Use 20

21 Land Use Housing Employment 21

22 Housing n Single Family Households O Autos 1 Auto 2+ Autos n Multiple Family Households 0 Autos 1 Auto 2+ Autos 22

23 Land Use Inputs- Housing 23

24 Employment nemployment Retail Service Government Education Other 24

25 Land Use Inputs Employment 25

26 Resources Base Year (Starting Point) n Census Data n Census Transportation Planning Package (CTPP) n Dunn and Bradstreet n Employment Development Department (EDD) n Local Surveys 26

27 Resources Future Year ngeneral plans npopulation projections ntiming of development 27

28 Population Forecasts 28

29 Putting the Puzzle n Network n Traffic Analysis Zone n Land Use Together n 4 Step Modeling Process Trip Generation Trip Distribution Mode Split Traffic Assignment 29

30 Four-Step Modeling Process n Trip Generation How many trips occur in each zone? n Trip Distribution How many trips travel from one zone to any other zone? n Mode Choice What travel modes do they use? n Trip Assignment Trips from one zone to another are assigned to travel routes. 30

31 Trip Generation Step 1 nestimates the Number of Trips that a Household or Business Will Produce or Attract 31

32 Trip Generation ntrips are divided into 5 trip purposes Home-Work Home-Shopping Home-Other Work-Other Non-Home Based 32

33 ; IF (AREATYPE<0.9) ; rural valley P[1]=P[1]+1.00 * ( 0.53*SF_0+0.89*SF_1+2.06*SF_2) ; H-W P[1]=P[1]+1.00 * ( 0.56*MF_0+0.94*MF_1+2.18*MF_2) ; H-W P[2]=P[2]+1.20 * ( 0.55*SF_0+1.02*SF_1+1.25*SF_2) ; H-S P[2]=P[2]+1.20 * ( 0.47*MF_0+0.88*MF_1+1.08*MF_2) ; H-S P[3]=P[3]+1.00 * ( 1.22*SF_0+2.97*SF_1+4.69*SF_2) ; H-O P[3]=P[3]+1.00 * ( 0.82*MF_0+2.21*MF_1+3.60*MF_2) ; H-O P[5]=P[5]+1.00 * ( 0.55*SF_0+0.55*SF_1+0.55*SF_2) ; O-O P[5]=P[5]+1.00 * ( 0.40*MF_0+0.40*MF_1+0.40*MF_2) ; O-O endif IF (AREATYPE>1.1) ; mountains P[1]=P[1]+1.00*0.85 * ( 0.53*SF_0+0.89*SF_1+2.06*SF_2) ; H-W P[1]=P[1]+1.00*0.85 * ( 0.56*MF_0+0.94*MF_1+2.18*MF_2) ; H-W P[2]=P[2]+1.20*0.85 * ( 0.55*SF_0+1.02*SF_1+1.25*SF_2) ; H-S P[2]=P[2]+1.20*0.85 * ( 0.47*MF_0+0.88*MF_1+1.08*MF_2) ; H-S P[3]=P[3]+1.00*0.85 * ( 1.22*SF_0+2.97*SF_1+4.69*SF_2) ; H-O P[3]=P[3]+1.00*0.85 * ( 0.82*MF_0+2.21*MF_1+3.60*MF_2) ; H-O P[5]=P[5]+1.00*0.85 * ( 0.55*SF_0+0.55*SF_1+0.55*SF_2) ; O-O P[5]=P[5]+1.00*0.85 * ( 0.40*MF_0+0.40*MF_1+0.40*MF_2) ; O-O 33

34 Trip Distribution Gravity Model Step 2 Step 2 The process of determining trip exchanges or the number of trips between each pair of zones 34

35 Mode Choice Step 3 n Walk n Bicycle n Motorcycle n Auto n Bus n Train n Plane n Ferry n Subway n Space Shuttle 35

36 Trip Assignment Step 4 npredicts Preferred Routes that Trips will Take nresults in Traffic Forecasts 36

37 Calibration/Validation n Calibrate with Base Year Survey Data n Validate with Base Year Traffic Counts 37

38 Validation by Facility Type Facility Percent RMSE Type Target Target Freeway +/- 7% 15% Rural Highway +/- 10% 40% Rural Road +/- 15% 40% Expressway +/- 10% 40% Urban Arterial +/- 15% 40% Collector +/- 25% 50% Overall 35% Source: FHWA: Calibration & Adjustment of System Planning Models,

39 Validation by Volume Group 39

40 Validation by Screenlines 40

41 The Model is Run 41

42 Limitations of Travel Models n Only as good as the inputs n Cannot predict changes in land use or attitudes n Average weekday model n Travel occurs only on the network No off road n Only as good as the inputs 42

43 Loaded Network Daily Volume AM Peak Hour PM Peak Hour 43

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46 Select Link Analysis Able to determine the origin and destination of all traffic that crosses the selected roadway section. 46

47 Select Link Analysis Separately assigns volumes that cross the selected link. Able to determine the origin and destination of all traffic that crosses the selected link. Output available in table format 47

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49 Selected zone volume TAZ Total roadway volume Select Zone Analysis 49

50 Select Zone Analysis Tracks volume from a single selected zone to all other zones. Also available in table format. Excellent for use in TIS analysis. 50

51 Select Zone Analysis Tracks volume from a single selected zone to all other zones. Also available in table format. Excellent for use in TIS analysis. 51

52 Select Zone Analysis Selected zone volume only Total roadway volume 52

53 Provides link analysis by zone districts District 1 = Fresno District 2 = Clovis District 3 = County Zone Compression 53

54 Zone Compression Provides link analysis by zone districts. District 1 = City of Fresno District 2 = City of Clovis District 3 = County of Clovis Etc. 54

55 The Fresno COG Travel Demand Forecasting Model Additional information available on our website at 55

56 The End 56