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
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.
Data collection purposes Travel Demand Models Demographic characteristics not avail from other data sources Trend analysis Borrowing data (transferability)?
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
Demographic Characteristics not always avail from other sources Volume counts, passenger counts do not include characteristics such as: –Vehicle ownership –Household income –Household size
Significantly more households in 2001 where there are more vehicles than there are drivers. 199 5 200 1 15 million 14.5 million 63 million 64.5 million 14 million 20 million 1.4 million 2.8 million Source: Patricia Hu, ORNL. Jan 2003
Borrowing Data/Transferability Primary data collection can be expensive. Sometimes you need to borrow data. NCHRP 365 (NCHRP 187) NPTS Transferability Pilot “Quick Response”
Maybe you decide that primary data collection necessary Let’s try some now.
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)
Constraints to Data Collection Three-legged stool –Quality –Quantity –Cost
What’s the hardest part of primary data collection? What do you think?
What’s the hardest part of primary data collection? Elaine’s opinion: –Getting the budget for the project –Response rates and potential sample bias –Reporting geographic information