chap 1 - Introduction to the 4-step Transport Planning...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Introduction to the 4-step Transport Planning Model Hong K. Lo Civil Engineering Hong Kong University of Science and Technology
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
2 4-step procedure 1. Trip generation forecasts the number of trips that will be made: the decision to travel 2. Trip distribution determines where the trips will go: the choice of destination 3. Mode usage (modal choice) predicts how the trips will be divided among the available modes of travel: the choice of travel mode 4. Trip assignment predicts the routes that the trips will take, resulting in traffic forecasts for the highway system and ridership forecast for the transit system: the choice of route of path Outputs of each step becomes inputs to the following step. This simplifies the actual decision process tremendously
Background image of page 2
3
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
4 Trip Generation • Journey: This is a one-way movement from a point of origin to a point of destination. • Home-based (HB) trip: Home is either the origin or the destination of the journey • Non-home-based (NHB) trip: neither end of the trip is the home of the traveler
Background image of page 4
5 • Classification of Trips – By Trip purpose: to work, school or college, shopping, social and recreational, and others – By time of day: peak and off-peak period trips
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
6 Typical Trip Generation Models • Develop trip generation expressions from survey data to convert estimates of horizon year development patterns into zonal productions and attractions for each trip purpose • Criteria: – provide good explanatory power of observed base year travel behavior – parameters of these trip generation expressions should be stable over time – the independent or predictor variable should be easily predictable with some precision for the horizon year • Two approaches: – regression analysis – cross-classification tables
Background image of page 6
7 Regression models • Model parameters and variables vary from one study area to another and are established by using base-year information • Once the equations are calibrated, they are used to estimate future travel for a target year. • Assumptions: – all the independent variables are independent – all the independent variables are normally distributed – the independent variables are continuous
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
8 Example Y = trips/household X1 = family size X2 = residential density X3 = total family income X4 = cars/household A, Bi = parameters determined through a calibration process from survey data • To derive Y for a future year, appropriate estimates of X1, X2, X3, X4 are substituted.
Background image of page 8
Image of page 9
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 38

chap 1 - Introduction to the 4-step Transport Planning...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online