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GIS Applications for Origin-Destination Surveys

Greg Spitz and John LobbResource Systems Group

gspitz@rsginc.comjlobb@rsginc.com

Daniel JacobsMTA Bridges & Tunnels

Wayne BennionWasatch Front Regional Council

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Origin-Destination (OD) Data

Critical basis of knowledge for transportation operations, modeling, and future planning

Essential for all transportation modes Often collected by DOTs and transit agencies,

but not (yet) often analyzed with GIS OD data are inherently spatial, and

visualization is key to understand them, thus the need for GIS

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Provide insights to: Who the customers are Why customers are traveling How long they are traveling, and Where they are traveling, etc.

Labor intensive data collection efforts Used to understand current demand and

plan for future demand Critical data for calibrating travel models

Origin & Destination Surveys

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GIS Tools in action

MTA Bridges and Tunnels— largest toll agency in US

Wasatch Front Regional Council &Utah Transit Authority— transit on-board survey

Two different agencies, modes, and application purposes

GIS the common denominator to solve issues for these different purposes

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2004 MTA B&T Origin & Destination Survey Conducted roughly every 8-10 years 2004 Study:

304,000 surveys distributed in CASH lanes 329,000 surveys mailed to E-ZPass customers Control Data collected in both CASH and E-

ZPass lanes with Pocket-PCs E-ZPass sample from B&T, PANYNJ, NYSTA,

NYSBA, and NJRSC comprising 99% of all transactions

Survey period 6AM to Midnight; Weekday, Saturday, and Sunday

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MTA B&T Survey TAZ Structure

All zones are based on zip codes Geocoding of survey data only necessary

to the zip code level Aggregations of zones used to form

“super zones”

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GIS using static maps

Static analysis with better presentation Easy to put together quickly Becoming more and more typical

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Survey Zone Map: Close-up

DRAFT

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Super Zone Map

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Example of Static Map using super zones:Bronx-Whitestone Bridge – Bronx Bound

OrderOrigin Super

ZoneDestination Super Zone Adjusted Volume

% of Total Traffic

1 Queens Bronx 9,520 20.2%2 Queens Westchester 8,989 19.1%3 LI Westchester 4,817 10.2%4 Queens Connecticut 4,816 10.2%5 LI Bronx 2,096 4.5%6 Queens NJ 1,914 4.1%

•All O-D pairs with greater than 4% of traffic

•All payment types

•Weekday

•Truck/taxi trips excluded

•6am to Midnight

•Total Auto Traffic (6AM to Midnight) is 47,030

•95% Confidence interval for these OD pairs is plus or minus 2.0%

20.2%

19.1%

4.1%

4.5%

10.2%

10.2%

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GIS Tool Purpose

Take geospatial data and make it easier to

visualize, analyze, and interpret

Allow more in depth analyses beyond static reports

Make the tool easy to use, so even a (skilled)

monkey can use it

Leverage GIS experts’ skills without taking too

much of their time

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How was the tool made?

ArcMap extension Access DB backend Currently developed to be a stand alone tool

(could be made to be network/web enabled) Simple user interface created using VB

development environment

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Income Distributions by Origin Zones

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Vehicle Occupancy by Origin Zone

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Specific Trip Analysis

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Travel Pattern Analysis

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2006 WFRC On-Board Transit Survey

3 surveys conducted in last 15 years

Data primarily used for travel model development and forecast refinement

2006 survey Surveyed riders on 90 bus routes

and the TRAX rail system Collected 5,600 surveys

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OD Data Mining is Cumbersome

Survey database has over 100 columns and 5600 rows (difficult to view all relevant variables at once)

TAZ number and/or address text may not be immediately recognizable (data is spatial)

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GIS Tool Purpose (WFRC)

Preliminary review of the data suggested that the 2006 survey transfer rates were unreasonable

Interest in examining individual survey records efficiently

Frequency Distribution of Transit Transfers (unweighted sample)

0

10

20

30

40

50

60

70

0 1 2 3 4 5

Transfers

% o

f T

rip

s

2006 2002

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GIS tool (WFRC)

Goals Local QA/QC

Efficiently examine each

record

Easy data editing/entry

Gain confidence in the data

used for model calibration

(e.g. transfer rates)

Features Custom ArcGIS application

Visualize transit path details

for one record at a time Routes

Origin/Destination

Boarding/Alighting

Data viewing/editing window

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Screen capture of GIS Tool

Reported data

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Survey Errors Identified

1. People reported multiple paths they sometimes take, rather than simply their current path (question 7)

2. Inconsistency between routes and OD pair

3. Geocoding errors

4. Illogical route sequence

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Example of Multiple Paths between same OD Pair

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Another example of multiple paths between same OD pair

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Summary

Application clearly identified obvious inconsistencies and errors, resulting in a more reliable database.

Visualization of these records would also be extremely helpful in assessing survey design and reducing respondent error.

Frequency Distribution of Transit Transfers (unweighted sample)

0

10

20

30

40

50

60

70

0 1 2 3 4 5

Transfers

% o

f T

rip

s

2006 Before2006 After2002

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User-friendly GIS tools developed for planners and analysts

GIS tools allow planners and others to drill down on the data

Tool interface confines the problem (both a good and bad thing)

Interface makes analysis much easier and doesn’t require in-depth software/data knowledge

Tools allow analysts to get more out of their data collection investment

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Questions ?

Please use the Microphone.