1. Generating an OD Table with Disaggregated Zone Structure for Land Development Program
12th TRB National Planning Application Conference
Xiaobo Liu, Ph.D.
Adam Lanigan
John Pavlovich, P.E.
Jacobs Engineering Group
299 Madison Ave
Morristown, NJ 07962

2. Introduction
The aggregated TAZ structure in regional planning models cannot provide adequate information for land development planning applications
How to employ detailed trip generation to create an OD table in the land development area while maximizing flexibility and efficiency for planning analysis?
The paper presents a simple, effective and efficient approach to investigate the traffic patterns with more accuracy

3. Determining TAZ Structure
Maximizing disaggregation of the TAZ structure would provide the most detailed information for planning purposes and traffic operational analysis
The disaggregated zones could be grouped into different sectors/blocks for trip generation to fit the land development programs
This could improve the flexibility and efficiency of updating the different elements during the planning procedure, such as updating the type and intensity of land development, various access plans, and geometric layouts

4. Proposed Procedure Trip Generation - block based
Converting Block to “Zone” Structure
Disaggregated P/A Assignment
Normalization
Land Development Program - block based
Setup Disaggregated “Zone” Structure
I-I Distribution
I-E /E-I Distribution
Regional Demand Model
Traffic Directional Distribution
E-E
Distribution
O-D Table

5. RIVER BEND DEVELOPMENT PLAN

6. RIVER BEND DEVELOPMENT PLAN
Issues:
Assess Multiple
Development Scenarios

7. RIVER BEND DEVELOPMENT PLAN
Issues:
Assess Multiple
Development Scenarios
Formulate Multi-Phase Land
Use Mix

8. RIVER BEND DEVELOPMENT PLAN
Issues:
Assess Multiple
Development Scenarios
Formulate Multi-Phase Land
Use Mix
Maximize Retail Component

9. RIVER BEND DEVELOPMENT PLAN
Issues:
Assess Multiple
Development Scenarios
Formulate Multi-Phase Land
Use Mix
Maximize Retail Component
Minimize Parking
Requirements

10. RIVER BEND DEVELOPMENT PLAN
Issues:
Assess Multiple
Development Scenarios
Formulate Multi-Phase Land
Use Mix
Maximize Retail Component
Minimize Parking
Fast Track analysis

11. RIVER BEND DEVELOPMENT PLAN
Issues:
Assess Multiple
Development Scenarios
Formulate Multi-Phase Land
Use Mix
Maximize Retail Component
Minimize Parking
Fast Track analysis
Set Final Street Network

12. Conventional Approach
Shortcomings:
No O-D Table
Lack of I-I trip generation that could be essential for urban area
Analyzing alternatives requires manual adjustments and traffic
assignment: time consuming, labor intensive, and error prone

13. Land Development Program
Development area consists of 12
blocks (A-L) based on roadway
boundaries
Each block has different land use
plan
Land development program including
the size of the development and land
use, was changed frequently by
developer to achieve max marketing
Roadway access was also updated
over several iterations to provide best
access to the site
32 zones proposed in the study area,
including 2 external zones and 30
internal zones.

14. Land Use Plan

15. Converting Trips from Block to “Zone”
The concept of distributing the trips produced and attracted by each block may be a bit abstract. Here is a breakdown: Think of the Zones (TAZs) as driveways. They represent the loading points for the trips generated by each block. You are essentially controlling how the trips get distributed between the individual driveways for a block. (i.e. 75% leave from this driveway, 25% from the other.)

16. Trip Generation TRIP GENERATION
To conduct the transportation analysis for land development in small area rather than regional analysis, ITE trip generation manual is applied for individual land uses.

17. Production/Attraction Assignment
Obtain trip productions and attractions for the land development
area from ITE Trip Generation Manual
Breakdown block-based Productions/Attractions into zone-based
First, we need to turn the generated trips into Production and Attraction trips.
Break down the Block based trips into Traffic Analysis Zones (TAZs or just zones) so that the trips produced by and attracted to (exit and enter from the Trip Gen stage) each block can be distributed, in favor of transportation analysis requirement.

18. Internal-External External-Internal Distribution
The proportion of the total trips generated from internal zones to
external zones (and external to internal) could be determined from a
regional demand model or local knowledge of the development area
Include pass-by trips to the development zones in the O-D distribution
specify how trips produced by and attracted to your TAZs relate to the External Zones in your model based on the relative proportion - obtained from regional planning model or field observation.

19. Internal-Internal Distribution
Production trips are used as the base
I-I trips are distributed using a gravity model based
on the internal zone activity (multiply or add weight)

20. External-External Distribution
Determine the distribution of external zone to external
zone traffic from a regional demand model
Credit the pass-by trips to the development zones
credited from the E-E trips

21. Total Vehicle Trips EXAMPLE: TOTAL TRIPS 100
LESS TRANSIT ADJUSTMENT
NET TOTAL TRIPS
LESS
INTERNAL/INTERNAL TRIPS
EXTERNAL/EXTERNAL PASS BY TRIPS 27
NET NEW VEHICLE TRIPS GENERATED

22. O-D Table and Applications

23. Results Phased Land Use Development Program by Block
Sizing of Parking Facilities
Fast-tracking of Street Infrastructure
Ability to Evaluate Changes in Land Use Elements to Respond to Economic Conditions

24. Questions?
Contact: John Pavlovich – Adam Lanigan – Xiaobo Liu –