KY 4/22 Module 1a Purposes of Data Collection

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KY 4/22 Module 1aPurposes of Data Collection
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Review of initial handouts

• Travel Survey Manual, TMIP, USDOT and EPA, 1996
• Travel Survey Manual Appendices, includes sample
  RFPs
• Travel Survey Course CD
• TRB Committee on Travel Survey Methods (A1D10)
  reports page

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Main differences between 1996 and TODAY

• Greater use of computers for data entry at all
  stages
• Greater use of GPS
• Future implementation of E911 with GPS in
  cellular phones
• Continuing decline in response rates
• Population sub-groups who rely solely on cellular
  phones.

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Data collection purposes

• Travel Demand Models
• Demographic characteristics not avail from other
  data sources
• Trend analysis
• Borrowing data (transferability)?

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Data collection purposes

• Travel demand models
• Trip Generation Rates
• Trip Length Frequency Distribution
• Model validation and calibration
• Mode choice models (FTA New Starts)
• Vehicle acquisition models

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Demographic Characteristics not always avail from
other sources

• Volume counts, passenger counts do not include
  characteristics such as
• Vehicle ownership
• Household income
• Household size

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Trend Analysis

• Daily weekday person trip rates
• Driver licensing
• VMT

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1969-2001 NHTS trends
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Annual Miles Per Driver
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Significantly more households in 2001 where
there are more vehicles than there are drivers.
2001
1995
15 million
14.5 million
64.5 million
63 million
20 million
14 million
2.8 million
1.4 million
Source Patricia Hu, ORNL. Jan 2003
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Borrowing Data/Transferability

• Primary data collection can be expensive.
  Sometimes you need to borrow data.
• NCHRP 365 (NCHRP 187)
• NPTS Transferability Pilot
• Quick Response

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Maybe you decide that primary data collection
necessary

• Lets try some now.

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Fill out a Travel Diary

• Your assigned travel day is
• Thursday, April 17
• Need a volunteer to tabulate
• Average of person trips per day
• Average of vehicles per driver (in households)

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Constraints to Data Collection

• Three-legged stool
• Quality
• Quantity
• Cost

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Whats the hardest part of primary data
collection?

• What do you think?

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Whats the hardest part of primary data
collection?

• Elaines opinion
• Getting the budget for the project
• Response rates and potential sample bias
• Reporting geographic information