1. OVERVIEW OF TRAVEL DEMAND FORECASTING

2. TDF RELATIONSHIPS Urban Activity Transit and Highway Networks
Travel Demand Forecasting
Process 1A

3. AVAILABLE TOOLS Sketch Tools Traditional Tools Micro-Analysis Tools
discussed in
this text
NUMBER OF ALTERNATIVES
Traditional Tools
Micro-Analysis
Tools
LEVEL OF DETAIL 1B

4. AVAILABLE TOOLS Sketch tools -- preliminary planning
Traditional tools -- tactical planning
Micro-analysis -- detailed, near-term planning 2A

5. AVAILABLE TOOLS short-range planning long-range planning SKETCH SKETCH
MICRO-ANALYSIS
TRADITIONAL 2B

6. RESOURCES & CONSTRAINTS
PLANNING PROCESS
GOALS
PROBLEM STATEMENT
CURRENT STATE &
FUTURE FORECAST
RESOURCES & CONSTRAINTS
OBJECTIVES
DEFINE ALTERNATIVES
ANALYSIS
EVALUATION
SELECTION
IMPLEMENTATION
MONITORING 3A

7. RESOURCES & CONSTRAINTS
PLANNING PROCESS
GOALS
PROBLEM STATEMENT
CURRENT STATE &
FUTURE FORECAST
RESOURCES & CONSTRAINTS
OBJECTIVES
DEFINE ALTERNATIVES
ANALYSIS
EVALUATION
TDF
SELECTION
IMPLEMENTATION
MONITORING 3B

8. THE 4-STEP APPROACH TRIP GENERATION TRIP DISTRIBUTION MODE CHOICE
HIGHWAY ASSIGNMENT
TRANSIT ASSIGNMENT 4A

9. Data Collection Trip Generation Transit & Highway Networks
Development
Policies
URBAN ACTIVITY
Transit
Policies
Land Use Forecasts
Regional growth
Highway
Policies
NETWORK
Trip Generation
Transit &
Highway
Networks
Data Collection
Trip Distribution
Mode Choice
Auto occupancy
Auto trips
Ped/Bike trips
Transit trips
Highway Assignment
Pedestrian/Bike
Assignment
Transit Assignment
TRAVEL
DEMAND
FORECASTING PROCESS
System evaluation 4B

10. URBAN ACTIVITIES 2 4 1 5 3 LAKE HH = 2500 EMP = 2156 HH = 1500
SUBURBS
CITY
HH = 1000
EMP = 5030
CBD 5 3
HH = 3000
EMP = 1437
HH = 1400
EMP = 2587
SUBURBS
CITY 5A

11. URBAN ACTIVITIES total population and employment estimates
BASIS OF ZONAL FORECASTS
total population and employment estimates
location behavior of people and businesses
local policies 5B

12. REGRESSION ANALYSIS TRIPS Slope = 1500/250 = 6.0
ZONE
AUTOS
TRIPS 1
230
1200 2
150
1130
4000 3
250
2700 4
380
3000
3000 5
160
1900
TRIPS 6 60
800
Slope = 1500/250 = 6.0 7
450
2800
2000 8
100
600 9
300
2800
1000
TRIPS = *AUTOS
Constant = 400
100
200
300
400
500
AUTOS
From NHI, 1994, p3-8 6B

13. CROSS-CLASSIFICATION
FAMILY SIZE
TRIPS = 2 1 2+ 3 4 2 5 7 3+ 8 11
TRIPS = 10
CAR OWNERSHIP
TRIPS = 3
TRIPS = 12
From NHI, 1994, p3-10 7A

14. TRIP GENERATION 2 4 1 5 3 LAKE P = 26,268 A = 17,740 P = 14,498
SUBURBS
CITY
P = 8980
A = 23,696
CBD 5 3
P = 33,255
A = 18,190
P = 13,461
A = 19,774
SUBURBS
CITY 6A

15. GRAVITY MODEL Conceptual Form Mathematical Form Tij =  of j Trips
Attractiveness
and accessibility
of all zones
of j
Trips
produced
at i
Tij = 
where:
Tij = trips from zone i to zone j
Pi = trips sent from zone i
Ai = trips received from zone i
Fij = travel time factor between zone i and zone j 3A

16. TRIP DISTRIBUTION 2 4 1 5 3 LAKE 1600 1730 1700 P=8980 1850 2100
SUBURBS
CITY
P=8980 5 3
1850
2100
SUBURBS
CITY 6B

17. MODE CHOICE characteristics of the trip maker
FACTORS CONSIDERED
characteristics of the trip maker
characteristics of the trip
characteristics of the transportation system 7A

18. MODE CHOICE 2 4 1 5 3 LAKE 640 bus 960 car 577 bus 1153 car 1133 bus
SUBURBS
CITY
P=8980 5 3
462 bus
1388 car
1050 bus
1050 car
SUBURBS
CITY 7B

19. TRIP ASSIGNMENT
P&R 5 4 3 2 1
Zone
Boundaries 8A

20. TRIP ASSIGNMENT Increasing levels of congestion Centroid Centroid4 2
Increasing
levels of
congestion 1
Centroid 1 5 3
Centroid
connector 8B

21. Specify Structure of Models and Level of Analysis
Input Base Year Travel Data
Input Present Transportation System Descriptions
Calibrate Forecasting Models
Input Base Year Zone and Household Data
Validate Models on Existing Data
Input New Transportation System Descriptions
Input New Zone Data
Forecast Travel
Evaluate Results 9A

22. Data Collection Trip Generation Transit & Highway Networks
Development
Policies
URBAN ACTIVITY
Transit
Policies
Land Use Forecasts
Regional growth
Highway
Policies
NETWORK
Trip Generation
Transit &
Highway
Networks
Data Collection
Trip Distribution
Mode Choice
Auto occupancy
Auto trips
Ped/Bike trips
Transit trips
Highway Assignment
Pedestrian/Bike
Assignment
Transit Assignment
TRAVEL
DEMAND
FORECASTING PROCESS
System evaluation 9B

23. NEW ISSUES Emphasis on management and operation Changing demographics
Changing legal requirements
Computer technology advances
10A

24. MODEL CHANGES Analyze operational improvements
Consider non-motorized modes
Consider access
Integrate transportation and land use models
Shift to behavioral models
Quick and reliable responses
10B