This presentation discusses the pilot survey results for the Greater Cincinnati Area Household Travel Survey. This was presented to the Association of Metropolitan Planning Organizations conference in Savannah, GA by Laurie Wargelin (Abt/SRBI) and Andrew Rohne (OKI Regional Council).

1. The Greater Cincinnati Area
Large-Scale (100%) GPS-Based
Household Travel Survey
ODOT, Greg Giamo and Rebekah Anderson
OKI, Andrew Rohne
Laurie Wargelin, Abt SRBI, Prime
Peter Stopher, PlanTrans, GPS
Kevin Tierney, Cambridge Systematics, Sampling
Sharon O’Connor, Resource Systems Group, Internet
1

2. Introduction
Quoting from the RFP Research Objectives . .
“This is the first large scale GPS-based survey
conducted in the United States, and therefore,
beyond the various logistical issues, it is
uncertain to what extent a GPS-based survey
is able to capture all the information available
in a diary-based survey. “
This presentation describes the processes
used for the Spring 2009 GPS survey pilot,
and discusses early findings.
2

3. Goals of this ODOT GPS Research
Project
Reduce substantial respondent burden
inherent in traditional travel diary recordings
Reduce under-reporting of trip data
Increase representative response rates
Provide the detailed geographic information
on route, speed, and location not captured by
traditional diary methods that can influence
the way travel is modeled
3

4. NEW FRONTIER: SCOPE
Recruit 6K “households (hh);”12-15K
members (persons).
Deploy GPS for age 12+; diaries for under
12.
Outcome: Minimum 3K usable households.
Prompted recall on 750-1,000 subsample
for trip inference check.
First, pilot with 400 hh to test protocols.
4

5. NEW FRONTIER: BETTER DESIGN
Advance Letter; Participants
Phone & Web Carry Device
Recruit; For Three
Fedex GPS Days
Devices
Geo-code Only Device
Home, Work, Collect
Returned Via
School, 2 Travel
Fedex,
Profiles Via
Frequent Shop Priority Mail,
Phone, Mail,
Addresses WebCourier
5

6. Survey Design – New Frontier
Children’s travel Logs - Collect limited activities and
travel information (to link with other household
members’ travel). Objective is to reduce burden and
meet child privacy concerns.
Six-minute phone or Internet recruitment interview--
three-day travel periods assigned.
Short-form household and person information forms
distributed and collected with GPS units.
Forms collect: (1) work and school locations, (2) two most
frequent household shopping locations, and (3) GPS usage
status for each member, each day.
6

7. NEW FRONTIER: SAMPLING
Address-based.
captures those not in RDD frame (i.e.;
cell-only) Now 15% to 30% of hhs
improves geographic representativeness
controls oversamples (i.e.; transit-
oriented areas)
Useful for advanced letters and Internet
recruit
Requires multi-process to contact
residents.
7

8. NEW FRONTIER: THE RECRUIT
Address-Based
Sample
UnMatched
Matched
Advanced Letter
Advanced Letter
w/ 800# & Web
w/ Web Pin
Pin
Opt-in by
Phone Recruit Internet Recruit Internet Recruit Phone from
800#
8

9. NEW FRONTIER: MORE QUICK
FACTS
Respondent profiles matched to PUMS.
Runs full year; includes seasonal travel.
Incentives tested in pilot.
$0 to $10 for 2 cells within matched
sample
$10 to $25 for 2 cells within unmatched
sample
9

10. NEW FRONTIER: THE GPS DEVICE
Easy; clear buttons; pocket -
size.
Charge lasts 3 days.
Instructions sent with
800#.
Data uploads via
USB port and
special software.
10

11. NEW FRONTIER: ANALYSIS
Managed by Australian partner, PlanTrans
(Peter Stopher).
GPS tells us where, when; not how, why.
Inferences about mode, purpose,
occupancy.
Confirmation from recall survey.
“Artificial Intelligence” software trained to
apply to full sample.
11

12. GPS Data Imputation and Verification
– PlanTrans Processing Methodology
Imputation of Trip Ends and Mode - Using a set of
rules that include movement of the GPS for 2 minutes
or more-or lack of movement, or a significant change
in speed, indicating a different mode being used.
Mode is imputed using the 85th percentile highest speed,
acceleration and deceleration, and matching to the street
networks and bus/train networks in a GIS.
Prompted Recall (PR) Verification - Return of
respondents’ travel (in Google Map form) in a web-
based format for verification. Detailed ability to
correct travel and purpose information, and add travel
cost (fare, driving and parking costs) and vehicle
occupancy for each trip.
12

13. NEW FRONTIER: PROMPTED
RECALL
13

14. Survey Design - GPS Data Processing
and Imputation
PlanTrans imputes purpose using the frequency and
duration of visits, the match to one of the collected
addresses (home, workplace, school, frequent shops),
and to available GIS land use data.
PlanTrans is also developing an additional rule-based
procedure for occupancy by family members by matching
trips from different family members by time, location,
and mode.
With the aid of the prompted recall, Artificial Intelligence
software will be trained, and these results will be applied
to rule-based software. In this process, PlanTrans will
attempt to add the capabilities to impute occupancy,
driver/passenger status, and possibly parking costs and
bus fares.
14

15. Processing and Verification of GPS
Data Files for Pilot
PlanTrans Processes the GPS Data Files Twice:
First for the Prompted Recall Survey
After the Prompted Recall Survey:
Deletions or additions are made to fix trips
Mode of travel is rechecked and identified for
each trip
Purpose of trip is rechecked and identified
Trip File is Created
Bi-Monthly Completed Data is Delivered to the Client
for Rechecking
15

16. PILOT: IMPUTATION RESULTS
Generally successful; more to learn.
Some GPS issues:
Brief stops are more difficult to
categorize
Some stops misread; travel delays…. or
trip destinations
Action: Add questions to prompted recall
16
Using GIS/GPS In Survey Research

17. Pilot Sample Plan Designed to Test
Response Rates and Incentives
Equal sample for Higher Transit Access and
Lower Transit Access geographic areas
Equal sample for Phone Matched and Non-
Matched Sample
Matched Sample offered $0 or $10 incentive to
complete
Non-Matched Sample offered $10 or $25
incentive to complete
17

18. Pilot Sample Results
100 100
81
80 80
Higher
Transit
Matched 60 Access
60
UnMatched Lower
40 Transit
40
19 Access
20
20
0
0
18

19. PILOT: INCENTIVE FINDINGS
$25 incentive doubled “unmatched”
completion.
Action: Use larger incentive
Also helped with low income, zero-vehicle
households.
Action: Target incentives
19

20. PILOT: SAMPLING OUTCOME
Web is key for those without land phones,
and some from matched sample.
Action: No changes
20

21. PILOT: THE GPS DEVICES
Tracking devices is a huge undertaking;
Multiple reminders, couriers needed.
Action: Revise instructions
Loss rate high.
Action: More GPS devices needed
Battery outages.
Action: Include chargers
21

22. Pilot Summary to Date
Address-based sampling was successful in
recruiting un-matched households (those
without land phone lines) to a GPS-Based
HTS
Internet recruiting is important for
capturing households headed by 18-34
year olds.
GPS household completion rates are
adequate and representative.
22

23. Pilot Summary to Date - Con’t
Requiring every household member to
carry a GPS unit for three days was not
considered an undue burden – paperwork
was greatly decreased.
Significant incentives and additional
efforts are needed to complete unmatched
households, low-income households, and
zero vehicle households.
Added trip accuracy reporting, route and
location information, and speed data
collected.
23

24. CURRENT PROJECT STATUS
Main study began in August.
Analysis continuing.
Major presentation at TRB in January.
Published paper likely.
24