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FOCUS MODEL OVERVIEW Denver Regional Council of Governments June 24, 2011 This presentation Ask Erik, Shahida and me questions throughout General Concepts Break model into four “stages” Then several steps within each stage Describe each step- it’s inputs and outputs Review stage inputs and outputs Move onto to next stage General Concept 1: What is a logit model? 2 minute version A model that calculates the utility of each choice from a set of discrete choices for a decision maker based on characteristics of the choice and the decision maker Suppose we have a trip we know is 3 miles long, it’s purpose is to eat a meal, it’s final location is the CBD, the person who made the trip is age 68, the person’s income is $28,000/year. What is the utility for this trip for various travel modes? We calculate the utility of taking transit for example based on the above information and the cost of transit, the time on transit, etc General Concept 1: Logit Models Many types: we use multinomial logit and nested logit Outcome is a simple closed form probability (not the choice) The choice must be randomly selected using a monte carlo process. Anything to add? Questions? General Concept 2: Monte Carlo Simulation If model only assign probabilities to a choice, how do we get a choice Monte carlo simulation Suppose you have three choices, one with probability 0.1, one with probably 0.4 and one with probability 0.5. Arbitarily, you assign choice one the range on the number line from 0 to 0.1 to choice one, from 0.1 to 0.5 to choice two and 0.5 to 1 to choice three. Then you generate a pseudo-random number from 0 to 1. If the number lands on the range assigned to the choice: you pick that choice For example, if you generate the number 0.6784536475, you would select choice 3 General Concept 3: Tours and Trips HOME Outbound, Away From Home Tour Half WORK Inbound, toward home tour half STORE TOUR-BASED MODEL TRIP-BASED MODEL •1 home-based work tour • 1 home-based work trip •1 shopping stop •1 non-home-based trip •1 home-based non work trip General Concept 4: Focus Model Flow: “Four” Steps STAGE 1: Make Population And Network STAGE 2: Run GISDK to Mode Choice FEEDBACK STAGE 4: GISDK Assignment STAGE 3: C# Logit Models to Create Trips General Concept 5: Mechanics: Code Types used in Model C# Code Logit Model Running; Model Manager GISDK Code Skimming, Assignment, I-E/E-E DIA Trips SQL Server Database Queries Data Storage Java For Population Synthesizer General Concept 6: Use of SQL Server Households, Persons and Points in SQL Server Persons, Trips, and Tours in SQL Server General Concept 7: GISDK: Old Model Highway Network Inputs Transit Network Inputs Socio-economic Inputs Network Processing & Data Preparation Area Type Trip Generation Highway Transit Skimming Skimming Trip Distribution Parking Cost Mode Choice Time-of-Day Highway Assignment Transit Assignment General Concept 8: Why are we doing this anyway? Data on ANY geography: all data is at a point level Using Most Demographic Characteristics of People Walking, biking, and transit Vehicle Miles Traveled households in LoDo in 2035 Average Bike Miles per persons age 70+ years old in 2020 Number of Cars owned by college students attending CU Boulder in 2015 Average Distance to Work by Restaurant Workers Review of General Concepts 1. Logit Models are models that make assign probabilities to a set of choices for an individual from a list of discrete choices. 2. The actual choice is made using a monte carlo process. 3. Travel in the model is made on a tour-level, and then a trip level. 4. We can divide the model into four stages. 5. We use four types of code in the model: T-SQL, C#, GISDK, and Java. 6. Much of the input and output data is stored in SQL Server. 7. We still have to run parts of our old GISDK code for path building, skimming and assignment. 8. We are doing this because we can get much finer detail and answer planning questions better using the model. Thinking points before we dive into the steps How is the new model activity-based? How is it disaggregate? How does the model actually do all this crazy stuff? How is the old model different than the new model? How does the model STILL simplify actual human behavior? Focus Model Flow: 28 Steps GISDK called from C#: For DIA, I-E, E-E and Commercial Trips GISDK called from C#: GISDK Preprocess Java: 3. Population Synthesizer C# 4. PopSyn Output Processor 5. Size Sum Variable Calculator 1. DRCOG Multi-Period Highway Preprocess 2. DRCOG Multi-Period Transit Preprocess 3. DRCOG Transit Preprocess 4. Trip Generation 5. Highway and Transit Skimming 6. Trip Distribution 7. Mode Choice FEEDBACK C# Regular Trips 8. Regular Work Location Choice 9. Regular School Location Choice 10. Auto Availability 11. Aggregate Logsum Generation 12.Daily Activity Pattern 13. Exact Number of Tours 14.Work Tour Destination Type 15.Work-Based Subtour Generation 19 . Tour Main Mode Choice 20. Tour Time of Day Choice 21. Intermediate Stop Generation 22. Trip Time of Day Simulation 23. Trip Time Copier 24. Intermediate Stop Location 25. Trip Mode Choice 26. Trip Time of Day Choice 16. Tour Time of Day Simulation 17. Tour Primary Destination Choice 18. Tour Priority Assignment 27. Write Trips to TransCAD GISDK called from C#: 28. Highway and Transit Assignment User Interface: How the steps look Focus Model Flow: Stage 1 STAGE 1: Make Population And Network STAGE 2: Run GISDK to Mode Choice FEEDBACK STAGE 4: GISDK Assignment STAGE 3: C# Logit Models to Create Trips STAGE 1: Make Population and Network Java: Population Synthesizer C# to process in database: Size Sum Variable Calculator; PopSyn Output Processor GISDK called from C#: GISDK Preprocess Creating networks for example Population Synthesizer ACS or PUMS Disaggregate Data Questions? Aggregate Data that We Need to Match: Economic Forecasts, Land Use Forecasts Disaggregate Population With the Right Portions Matching the Economic and Land Use Forecasts