1. Transportation Planning Data Needs and Sources CE 451/551 Iowa State University Reg Souleyrette Source: Transportation Planning Handbook unless otherwise cited

2. Technical Process - 4 principal steps Inventory conditions Analyze data to determine relationships Forecast future performance Evaluate forecasts, recommend improvements

3. Typical Information Requirements Population and Employment Land Use Economic Base Transportation System Travel Patterns Social and Value Factors Financial Resources Ordinances, Statutes and Regulations Good models require good data!

4. Data by geographic subsystem (in order of increasing area) point in urban space is a house number assessor parcel block face block block group grid unit tract Traffic Analysis Zone (TAZ) (model level) zone, ring, sector, or district (used to adjust TAZ data in the aggregate, e.g.for a growth forecast) political jurisdiction region

5. Data Sources Census CTPP US Census/American Community Survey (ACS) State Employment Commission (Iowa Work Force Development) Market research listings Building permits Parcel databases Very interesting mapping application using census data. http://projects.nytimes.com/census/2010/explorer?hp

6. Census

8. Census data and related summaries Decennial Census summary files SF 1 (Summary File 1) base with all census data Short-form, basic population data SF 3 ( Summary File 3) - Long form summaries - 1 of 6 households received the Long form transportation data relate only to Work trip Public Use Micro-Sample Data (PUMS) 5% sample of long form

9. Long Form (SF 3) transportation elements Transportation questions: (within the week of the April 1 survey) Did this person do ANY work for either pay or profit? At what location did this person work? How many people, including this person, usually rode to work in the car, truck, or van? What time did this person usually leave home to go to work? Address of work site? How many minutes did it usually take this person to get from home to work

11. What is the CTPP 2000? The Census Transportation Planning Package is a set of special tabulations from the long form of the decennial census designed by transportation planners for transportation planners It summarizes the data At Residence At Workplace Flows between Home and Work

12. Where does the data come from? Long Form

13. For the U.S. as a whole, about one (1) in six (6) households received the Long Form questionnaire Who got the Long Form? Who got the Long Form? 17%

14. Key Long Form questions Key Long Form questions Place of Work Means of Transportation to Work Carpool Occupancy to Work Departure Time for Work Travel Time to Work Vehicles Available    

15. What are the CTPP 2000 Products? Tabulations at Residence Tabulations at Workplace Flows between Home and Work Part 1Part 2Part 3 Part 1Part 2 Part 3

16. Where do I get the CTPP? http://www.transtats.bts.gov/ ASCII Too

17. What about the data? Let’s Look at the Details So how does this thing work?

18. Tables—Lots of Tables 121 Tables of Residents’ Based Data 68 Tables of Work Place Data 68 Tables of Work Place Data 14 Tables of Flow Data 14 Tables of Flow Data

19. Variables-- Lots of Variables Variables-- Lots of Variables Journey-to-Work Work Location and Mode Departure and Travel Time Arrival Time (Calculated)Household Income Nos. Vehicles Available Size and Nos. Workers Person Worker Status Age, Sex, Race, Hispanic Origin, Disability Workers

21. What is a “Universe”?

23. Disclosure Review Board

25. Mode to Work Circa 1990 For 2000 (ROUNDED) Total352350 (not 355!) Drive Alone212210 Carpool4645 Transit5960 Walk3335 Bike24 Example of Rounding True Total 354

26. No record threshold Must have 3 unweighted records

27. CTPP main page – 2000 CTPP 2000 CTPP – BTS TranStats web site BTS TranStats web site – Appendix E: CTPP2000 – Standard Tabulations – Sorted by Table Number; Local copy Appendix E: CTPP2000 – Standard Tabulations – Sorted by Table NumberLocal copy – For variable levels, click hereclick here

28. But what about the ACS? What is the American Community Survey? Replacement of the Long Form Continuous Survey Methodology Conducted Monthly (diaries) Produces Rolling Average Data

29. Why have an ACS? Eliminate the Census Long Form for 2010 and Thereafter Eliminate the peak in Congressional funding Eliminate the peak in hiring andtraining Census takers

30. Decennial Census ACS Sample: 1 in 6 Hhlds (17% Sample) Sample: 1 in approx 40 households each year (2.5%/yr 12.5% @ 5 yrs) Time reference: April 1, 2000 or April 1, 2010 (Last Week) Time reference: Continuous including all 12 months Data is outdated quickly Requires accumulation over multiple years for small area reporting Main differences between Census Long Form and ACS

31. Some Emerging Issues People might be counted twice, e.g. once at summer cabin and once at a “permanent home”. Or once at university and once at parent’s home. Areas with seasonal populations, e.g. due to “snow bird” migration, and due to school enrollments, with housing occupancy that varies from 95% to 40% might show up as 80%.

32. Sample Error is larger because the number of census forms collected each year are smaller. Changes of plus or minus 2% may be due to Sample Error and do not reflect measurable change. Understanding Sample Error

33. NO! Cannot compare ACS directly to Decennial data? Cannot compare ACS directly to Decennial data? Carpooling Share You

34. Can’t I compare ACS directly to Decennial data Can’t I compare ACS directly to Decennial data Why Seasonality (12 months instead of "April 1") (different jobs and workers, especially in summer) Group Quarters currently not in ACS (plan to add GQ in the future) Representation ACS has only 1/3 of the nation’s counties (will include ALL counties starting in July 2004) Non-response follow-up differences Data collection period (ACS is very long, compared to very short in decennial)

35. Mail-back rates for Minority populations may be significantly lower A Census Bureau report says that mail-back response rate in neighborhoods that are predominantly African American or Latino are ½ that of predominantly White neighborhoods. Census says they plan to change non- response follow-up plan in these neighborhoods.

36. Census Transportation Planning Package (CTPP) Same data as in the long form Pre-processed tables plus capture tools to formulate your own data tables and maps are provided CTTP Tables of three summary types 1) At residence (Part 1) 2) At work place (Part 2) 3) travel between work and home (Part 3) Prepared sets of Tables from CTPP include: 1) 121 Tables of Residents’ Based Data 2) 68 Tables of Work Place Data 3) 14 Tables of Flow Data TransCAD also has processing tools

37. BTS TranStats web site For table descriptions, see: click hereclick here For variable levels, see: click hereclick here CTPP online access

38. TIGER files Census 2000 TIGER/Line Data (from ESRI)

40. NHTS data can be used to investigate topics in: transportation safety congestion mobility of various population groups relationship of personal travel to economic productivity the impact of travel on the human and natural environment

41. NHTS Long term trends 26,000 national samples 40,000 “add-on” samples 24 hr (local) and 28 day (long distance) diaries 1977 and 1995 ATS (long dist) 2001 did both local and long dist.

42. Other internet sources Census Fact Finder Ed the Fed http://www.surveyarchive.org/index.html Iowa Department of Transportation (IowaDOTMaps.com) Iowa Department of Transportation ISU Geographic Information Systems (GIS) Facility – Geospatial Data Explorer Geospatial Data Explorer – Orthophphotos Orthophphotos http://earth.google.com/ Iowa Department of Natural Resources ISU’s SETA (Social and Economic Trend Analysis)SETA Quarterly Census of Employment and Wages (ES202) MPOs, cities and other state DOTs – much more

43. More data sources windshield surveys land use maps tax assessor files business license files zoning maps local records, city directories, rural directories (for outlying areas) building and occupancy permits utility companies business data files (may be confidential) Polk directories, Dun and Bradstreet and others Telephone directory Aerial remote sensing and satellite images State department of finance Local planning departments

44. Studies Volume Studies – Average daily traffic counts – Hourly Counts – Peak Hour Counts – Cordon Counts – Screenline Counts – Projected flow (future volumes) Capacity Studies – Freeway and multilane highway segments – 2-Lane highways – Signalized intersections Pedestrian Studies – Volumes – Flow characteristics – Capacity analysis – Walking speed Mass Transit Studies – Transit capacity and level of service – Transit origin-destination studies – Load and boarding checks – Speed and delay Parking Studies – Supply and demand – User characteristics – Occupancy rates – Turnover rates