Travel Demand Modeling: A Comprehensive Overview

 
Travel Demand Modeling
 
1
 
Travel Demand Modeling
(4-step models)
1.
Trip Generation
2.
Trip Distribution
3.
Mode Choice
4.
Trip Assignment
 
4-step Models
 
1.
Trip Generation: 
How
many people travel?
2.
Trip Distribution: 
What
are the travel patterns for
the study area?
3.
Mode Choice: 
What travel
modes are used?
4.
Trip Assignment: 
What
trip paths will be followed
through the transportation
network?
 
2
 
Examples of 4-steps Models
 
3
 
Trip Generation
 
Trip Distribution
 
Mode Choice
 
Traffic
Assignment
 
 
4
 
Define Trip Production and
Attraction
 
 
5
 
In-class activity
 
A worker leaves TAZ 1 in the morning
to go to work in TAZ 6
. 
In the evening,
same worker comes back TAZ 1.
 
How many trips?
 
Example
 
7
 
In-class Activity
 
Step 1: Trip Generation
 
Trip Production Modeling Techniques:
Regression Techniques
Cross Classification (or category) Analysis.
Trip attraction models
 
8
 
In-class activity
Estimate Zone Productions
 
9
 
10
 
Trip
Attraction
Models
 
In-class Activity
 
 
11
 
Cross Classification Models
 
Step 1:
 create matrix that shows number & percentage
of HHs as function of HH attributes (most common size,
income, auto ownership, # of workers)
Step 2:
 create matrix that shows average number of
trips per HH versus HH attributes
Step 3:
 Use O-D data from survey to determine
percentage of trips by trip purpose as function of HH
attributes
Step 4:
 calculate total number of trips per day generated
in zone
 
12
 
Balancing Productions and
Attractions
 
Trip generation process usually results in non-
equal numbers of total production & attraction
Trip productions considered more accurate
(based on survey data)
Trip attractions modified so that total trip
attractions are equal to total trip productions
Adjustment factor: f
a
 = 
Σ
P
i
/
 Σ
A
i
, i – zone
Adjusted attractions for each zone:
 
A
adji
 = A
i
*f
a
 
13
 
In-class Activity
 
14
 
Source: Traffic & Highway Engineering, Garber & Hoel
 
Balance trip production and attractions for the
following two senecios.
 
Scenario 1
 
Scenario 2
 
Sources of Uncertainties in Predicting
Number of Trips
 
The model development
The prediction of future
demographics
The use of the model for predicting
the future
 
15
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Explore the essential components of travel demand modeling, including trip generation, distribution, mode choice, and assignment. Learn about trip production, attraction modeling, and practical applications through in-class activities and examples.

  • Travel demand
  • Modeling techniques
  • Trip generation
  • Mode choice
  • Transportation network

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  1. Travel Demand Modeling Travel Demand Modeling (4-step models) 1. Trip Generation 2. Trip Distribution 3. Mode Choice 4. Trip Assignment 1

  2. 4-step Models 1. Trip Generation: How many people travel? 2. Trip Distribution: What are the travel patterns for the study area? 3. Mode Choice: What travel modes are used? 4. Trip Assignment: What trip paths will be followed through the transportation network? 2

  3. Examples of 4-steps Models Trip Generation Mode Choice Zone Trip Zone Trip Mode 1 Mode 2 Attractions Productions 1 2 3 1 2 3 Traffic Assignment Trip Distribution 1 2 3 Route 1 Route 2 Route 3 1 2 3 3

  4. 4

  5. Define Trip Production and Attraction 5

  6. In-class activity TAZ 1 TAZ 6 Home Work A worker leaves TAZ 1 in the morning to go to work in TAZ 6. In the evening, same worker comes back TAZ 1. How many trips?

  7. In-class Activity Example 7

  8. Step 1: Trip Generation Trip Production Modeling Techniques: Regression Techniques Cross Classification (or category) Analysis. Trip attraction models 8

  9. In-class activity Estimate Zone Productions In TAZ 235, you have following socioeconomic data; Households (HH): 23,000 Average Annual Income per HH: $30,000 Average cars per HH: 1.4 Average number of people per HH: 2.1 Average number of workers per HH: 1.4 Total Office Space: 2,000,000 ft^2 Total Retail Space: 5,000,000 ft^2 Estimate zone productions and attractions? ??????????????? = 0.3 + 0.82 ??????? 0.0024 ???? 0.041???? 4.7? 06 ?????? 9

  10. Trip Attraction Models 10

  11. In-class Activity 11

  12. Cross Classification Models Step 1: create matrix that shows number & percentage of HHs as function of HH attributes (most common size, income, auto ownership, # of workers) Step 2: create matrix that shows average number of trips per HH versus HH attributes Step 3: Use O-D data from survey to determine percentage of trips by trip purpose as function of HH attributes Step 4: calculate total number of trips per day generated in zone 12

  13. Balancing Productions and Attractions Trip generation process usually results in non- equal numbers of total production & attraction Trip productions considered more accurate (based on survey data) Trip attractions modified so that total trip attractions are equal to total trip productions Adjustment factor: fa = Pi/ Ai, i zone Adjusted attractions for each zone: Aadji = Ai*fa 13

  14. In-class Activity Balance trip production and attractions for the following two senecios. Scenario 2 Scenario 1 Unbalanced NHB Trips NHB Productions NHB Attractions 1 240 100 2 400 200 3 160 300 Total 800 600 Source: Traffic & Highway Engineering, Garber & Hoel 14

  15. Sources of Uncertainties in Predicting Number of Trips The model development The prediction of future demographics The use of the model for predicting the future 15

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