Modal Split

Posted in Operations and Supply Chain Terms, Total Reads: 327
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Definition: Modal Split

Modal Split is the percentage of travellers using a particular type of transportation or number of trips using said type. In freight transportation, this may be measured in mass. Modal spilt is the third stage of the travel demand modelling. The trip matrix generated from the problem is divided into number of matrices each representing a node.


The below is the flowchart of a travel demand modelling



Types of Modal Spilt Modals

1) Trip end modal spilt models

The application of mode choice models over the population results in trips split by mode, hence modal split modelling. In the past (especially in the USA) personal characteristics were considered to be the most important determinants of mode choice and attempts were made to apply modal split models immediately after trip generation. In this way the different characteristics of the individuals could be preserved and used to estimate modal split. At this level there was no indication to where these trips might go, the characteristics of the journey and modes were omitted from these models. This approach was consistent with a planning view that as income grew – individuals would acquire cars and would want to use them. These modal split models of this time related the choice of mode to features like income, residential density, car ownership and the availability of reasonable public transport. These trips in the short run were accurate, in particular if public transport is available in an area. These models were seen to be defeatist in that any changes to the cost of a trip or the mode used would have no effect on modal split according to these trip-end models.

 

2) Trip interchange modal9split models

Modal split modelling in Europe are post distribution models. These are models applied after the gravity or other distribution model. This approach has the benefit of facilitating the inclusion of the characteristics of the journey and the alternative modes available to undertake these trips. The early models typically included one or two characteristics of the journey (in vehicle travel time). One important limitation of these models is that they can only be used for trip matrices of travellers with a choice available to them. This would mean the matrix of car available persons, although modal split can also be applied to the choice between different public transport modes.

 

3) Aggregate and disaggregate models

Mode choice could be aggregate if they are based on zonal and inter-zonal information. They can be called disaggregate if they are based on household or individual data.

 

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