modelling transport in dublin

8/2/2019 Modelling Transport in Dublin

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Modelling Transport in Dublin


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Historical Background to Modelling Transport in Dublin

- 1991: Dublin Transportation Initiative: Phase One

- 1992 1994: Dublin Transportation Initiative: Phase Two

- 1993 2001: Economic Expansion (Celtic tiger)

- 1995: Final DIT Phase published

- 1998 2001: Dublin Transportation Office conducted an up date of the strategy

- 2001: DTO Published the Platform for Change

- 2005: Government announces Transport 21

- 2007- present: DTO up date of the strategy


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Four-stage Modelling in the DTI

The DTI followed a traditional four-stage approach. The model was chosen due toits ability plan at the strategic level for the medium to long term.

Special features of the model included:

-A two level hierarchal zoning system combines robust forecasting of socio-economic and travel activity variables with the detail required for accurate modechoice and assignment.

- A network system with two different levels of detail: buffer and simulation links,this reflecting the complexity of congestion phenomena in the critical aspects of theDTI

- land-use transport interaction models to look at the strategic consonance of

transport investment and urban development- disaggregate licence holding and car ownership models to handle the mostimportant determinants of travel behaviour in Dublin


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-Disaggregate data collection and mode choice model estimation for sensitive andaccurate treatment of modal split, one of the key transport policy issues for theregion

- a sound equilibrium framework handling mode choice and assignmentsimultaneously for stable and repeatable results for model runs

SATURN

SATURN and SATCHMO (SATURN Travel Choice Model) were used to model;

-multi-modal, addressing all modes equally

-Capable of responding to a wide range of policy instruments

-Flexible, fast cost effective

-Comprehensive in its results interpretation


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DATA Collection

Three sets of data collection were taken as part of the DTI

- road side interviews

- on-board bus interviews

- rail passenger surveys

The following data was also used in the DTI

- land use data

- disaggregate mode choice data


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Trip Generation and Attraction Model

Growth factors were developed for car available and car not available. Two timeperiods were considered, 08:00 09:00 and off peak time period of 14:00 15:00.


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The following steps where used to create the generation model:

Step 1: bring zonal 1986 and 1991 data to a common 1991 base.Step 2: input forecast year land use scenarios

Step 3: calculate forecast year car availability

Step 4: forecast future year zonal trip ends

Step 5: calculate car available (CA) and non car available trips (NCA) by journeypurpose to derive zonal total CA/NCA trip ends. Calculate growth factors.

Step 6: calculate the growth in slow mode trips from 1991 to the forecast year

Step 7: calculate number of slow mode which are CA/NCA and the trips which willtransfer to mechanised modes over the projection period and derive themechanised mode growth factor.

Step 8: combine mechanised mode/slow mode growth factor to derive zonal tripend growth factor to be input into distribution model stage.


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Peak Model

Off peak model

This model was the same as the peak model with eight different variations

Home work

2 0 1 12 0 0 1 1 9 9 1

1 9 9 1

. j j j j

E D D

E =

2 0 1 1

2 0 0 1 1 9 9 1 1 9 9 1

. j H W H W j j j

E D D

E =


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Zonal Car Ownership

This was calculated by using CSO data per DED on car ownership, and it used thefurness iteration technique

Where:

Output trip matrix (in this case future year matrix)

Input trip matrix (in this case base year trip matrix)

A balancing factors

ij ij i j

ij

ij

j j

T t A B

T

t

B

=

=

=

=


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Generalised Cost, Mode Split and Assignment

In the DTI the generalised costs were calculated by using the following:

-In vehicle time (IVT) in the car, bus, rail, other mode combination

- walk time (WK) to/from bus stop or rail station and from car park to finaldestination. This also includes any intermediate walk time (transfers)

- waiting time (WT) for public transport services or excess time (EX) whilesearching for car parking

-Fares and vehicle operating costs (VOC) as perceived by drivers. Both cansometimes be represented as a function of travel distance.

- parking charges (PK) applicable to the journey if any

- mode specific constant or penalty, reflecting other intrinsic perceptions of eachmode of transport, such as convenience comfort and reliability


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1 2 3 4 5 6

1 1 1 1 11 2 3 4 6

car

pt

GC a IVT a WK a EX a VOC a PK aGC a IVT a WK a WT a FARE a

= + + + + +

= + + + +


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2007 Exam


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2006 Exam


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2005 Exam


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modelling transport in dublin

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