1. Transportation Modeling – Opening the Black Box

2. Agenda 6:00 - 6:05Welcome by Brant Liebmann 6:05 - 6:10 Introductory Context by Mayor Will Toor and Tracy Winfree 6:10 - 6:15 Finish Survey Form 6:15 - 7:00 Powerpoint Presentation 7:00 - 7:30 Q&A

3. Regional Connections

4. Frequently Asked Questions What is a model and how is it used in the Transportation Planning process? Why model? How does the model work? How accurate is it? What can the model really tell us and not tell us? How does modeling help to address the 1996 Transportation Master Plan (TMP) objectives?

5. 1996 Transportation Master Plan Objectives From Model? Maintain 1994 Vehicle Miles of Travel (VMT) Reduce Boulder residents’ Single Occupant Vehicle (SOV) Travel to 25% Less than 20% of roadways congested Improve Air Quality no yes

6. No Long-Term Traffic Growth Goal: 2.4 Million VMT

7. Improve Air Quality

8. Not Addressed by TMP Objectives How is the transportation system used? How does the transportation system work? How does the transportation system fit in the community? Safety Quality of life

9. Integration with Other Studies TMPJobs/PopTDM Traffic Modeling Job Projections

10. Transportation Analysis TMP Update|Jobs/Population | TDM Infrastructure Alternatives Multi-modal Corridors Regional Connections Roadway Travel Demand Model TransitBicyclePedestrian Spatial Analysis/Geographic Information Systems Multi-modal Corridor Indicators TDM Analysis Tools

11. What is a Model? A model is a mathematical representation of real world behavior for testing assumptions of future land use and transportation. Land UseTransportation Model Information for Decision-Making

12. Types of Models Historical Growth/Trend Analysis Intuitive - Indicator Method Manual/Spreadsheets –Generate –Distribute –Assign Four Step Models

13. Why Model? Play “What-if…?” Consistency Evaluation of multi-modal options Required for Federal Funding Land use, transportation, and air quality relationships Considers all trips to, through, from, and within the Boulder Valley

14. Typical Four-Step Models Who travels? Why do they travel? How much do they travel? Where do they go? How do they get there? When do they travel? What route do they take?

15. Four-Step Process Trip Generation Trip Distribution Mode Analysis Assignment Socioeconomic Data Roadway Network Regional Transit Network Transit Ridership Roadway Volumes Performance Report How many trips? Where will they go? What mode? What route? Identify needs Alternatives analysis INPUT OUTPUT 4 STEPS

16. Model Inputs for Estimating Travel Travel survey data Distance Roadway Capacity Travel time/Speed Activity Household Size and Income Home Work Other

17. Socioeconomic Data What is it? Population, Households, & Employment Where does the data come from? U.S. Census State Employment/Tax Records Parcel/Zoning/Permit Data Future: Jobs/Population Study How is it represented in the model? aggregated into Traffic Analysis Zones (TAZs) with greater detail in Boulder used to generate travel demand

18. Socioeconomic Data 1998 Data2020 DataLand Use Data

19. Transportation System Networks What is it?Roadway and transit networks Where does the data come from? Aerial photography City and regional plans Departmental inventories/maps How is it represented in the model? Links and nodes Increased detail in Boulder

20. Transportation System Networks

21. Travel Surveys Regional –Household Survey (1997) –On-board Transit Survey (1997) –Commercial Vehicle Survey (1998/99) –External Station/Cordon Survey (1998) Boulder –Travel Diary Study (2000) –Transportation Survey of Residents (1999) –Employee Use Survey (1999) Now is a good time to update the Boulder Model!

22. Trip Generation Trip-making based on Household and Employment data –Generally, households produce trips –Generally, employment locations attract trips Boulder Residents: about 6 trips per person per day

23. Trip Generation Trip Types (PM Peak Period)

24. Trip Distribution Identifies the start and end points of each trip

25. Length of Trips Home-Work Home-Shop Home-Recreation Home-Other Not Home-Not Home Trip Types Boulder residents: about 27 miles/day

26. Mode Split Mode of Travel by Boulder Residents Source: Boulder Travel Diary Report, 2001

27. Traffic Assignment Determines travel routes by minimizing travel time

28. Traffic Assignment Travel by time-of-day

29. Model Validation Statistical analysis that ensures the model replicates current, observed conditions (e.g., traffic counts). A model must first be validated to current conditions before it can be used to forecast future travel.

30. Observations: The Good, Bad, and Ugly Some communities: Don’t invest in modeling resources and maintenance Try to answer the wrong questions with a model Have a “good” model that is not supported with good data Don’t include enough detail in the model Have models with unreliable forecasts Rely too much on the model’s numbers

31. Model Accuracy Traffic counts vary 10-20% Dependent on Socioeconomic Data input We don’t model everything We don’t know what it will really be like in 25 years Conclusion: Model can estimate general travel characteristics Model will not answer how much travel will be in front of my house in 25 years Model requires interpretation

32. Interpretation Actual Counts ModelTraffic Estimates ?Forecasts Current Future

33. Travel Forecasting and Assessment Process Travel Infrastructure Finance TDM

34. Travel Demand Management Model Output TDM Measures Adjusted Forecasts by Mode

35. Decision-Making Transportation System and Services TDM Finance Travel Supply Demand What’s the balance?

36. Performance Vehicle Miles of Travel (VHT) Vehicle Hours of Travel (VHT) Average Travel Speeds Congestion Delay Transit Ridership/Mode Split Transit/Auto Travel Times

37. Vehicle Miles of Travel Vehicle Miles of Travel per Day Level of Service

38. Travel Patterns

39. Colorado Springs Alternatives Analysis

40. Supply-Demand Analysis Demand SupplyDifference

41. Transit Planning and Operations

42. Air Quality Boulder Valley Travel Model EPA Mobile Model Vehicle Miles of Travel, Link Speeds Emission Factors By Speed (grams per mile) Emissions (grams)

43. Air Quality Gridded Overlay Link-based Emissions Zone-based Emissions

44. Corridor Analysis Modeling Intersection Turn Movement Forecasts Synchro Sim Traffic