The Fresno COG Travel Demand Forecasting Model How the Pieces Fit Together Mike Bitner PE, Senior Transportation Planner Council of Fresno County Governments 1
COG Modeling Staff Mike Bitner Kathy Chung Kristine Cai Lindsey Monge 2
What is Ahead 3
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
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
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
Planning Tool! Not Perfect 7
Model Users n Cities n County n Caltrans n Private Consultants n Developers n COG 8
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
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
Putting the Puzzle n Network Together 11
Transportation Network n Network Based on adopted general plans Replicates freeways, expressways, arterials and collectors existing & future Local roads not generally modeled 12
Network Development Network Development Using County GIS Street File 13
Links and Link Attributes n Nodes n Name n Distance n Facility Type n Lanes n Speed n Project ID n Improvement Year 14
Nodes n May represent intersections or other decision points n Nodes are described by coordinates for location purposes 15
Putting the Puzzle Together n Network n Traffic Analysis Zone 16
Urban Traffic Zones The basic geographical unit for distributing population and Employment within a study area. 17
Rural Traffic Analysis Zones 18
Traffic Analysis Zones Zone Data Households Single & multiple family Employment Retail Service Government Education Other 19
Putting the Puzzle Together n Network n Traffic Analysis Zone n Land Use 20
Land Use Housing Employment 21
Housing n Single Family Households O Autos 1 Auto 2+ Autos n Multiple Family Households 0 Autos 1 Auto 2+ Autos 22
Land Use Inputs- Housing 23
Employment nemployment Retail Service Government Education Other 24
Land Use Inputs Employment 25
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
Resources Future Year ngeneral plans npopulation projections ntiming of development 27
Population Forecasts 28
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
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
Trip Generation Step 1 nestimates the Number of Trips that a Household or Business Will Produce or Attract 31
Trip Generation ntrips are divided into 5 trip purposes Home-Work Home-Shopping Home-Other Work-Other Non-Home Based 32
; 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
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
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
Trip Assignment Step 4 npredicts Preferred Routes that Trips will Take nresults in Traffic Forecasts 36
Calibration/Validation n Calibrate with Base Year Survey Data n Validate with Base Year Traffic Counts 37
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, 1990 38
Validation by Volume Group 39
Validation by Screenlines 40
The Model is Run 41
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
Loaded Network Daily Volume AM Peak Hour PM Peak Hour 43
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Select Link Analysis Able to determine the origin and destination of all traffic that crosses the selected roadway section. 46
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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Selected zone volume TAZ Total roadway volume Select Zone Analysis 49
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
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
Select Zone Analysis Selected zone volume only Total roadway volume 52
Provides link analysis by zone districts District 1 = Fresno District 2 = Clovis District 3 = County Zone Compression 53
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
The Fresno COG Travel Demand Forecasting Model Additional information available on our website at www.fresnocog.org 55
The End 56