International Choice Modelling Conference, International Choice Modelling Conference 2017

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Does the design of the environment affect the willingness to transfer between modes?
Alejandro M. Tudela, Carla Duran, Juan Antonio Carrasco, Arnoldo Tapia

Last modified: 28 March 2017

Abstract


Promotion and use of public transport requires to take into account several factors which might be affecting people’s decisions regarding this process. Transferring between modes is a relevant issue in the case of massive public transport systems, where people might be requested to transfer between railways lines o between a railway line and a bus service. The main research question is whether the transference environment might affect people’s decisions to use a combined service (rail to rail or rail to bus service) instead of using a direct bus service. Transference environment refers to the existence of a close transfer area, instead of an open air area, and the existence of different physical levels for transferring between modes.

 

A stated preference experiment was designed to investigate the role of the transfer environment, using a classical design approach. The case study is based on the Great Concepcion area, Chile, where a new line service connecting the CBD with an existing train service, already operating, has been under study. People were asked to elicit their preference among a train to train service, train to bus service or direct bus service, all of them connecting their origin and destination. The attributes describing the choice experiments were cost, in-vehicle travel time, waiting time, transfer time, close-open transfer environment and existence of different levels for transferring. A total of eight choice experiments was presented to respondents. Graphic information was used to support the application of the choice experiments. Besides, sociodemographic and psychosocial information of respondents was also gathered, using appropriate tools.

 

Must be pointed out that psychosocial aspects were collected using psychometric tools, framed in the Interpersonal Behaviour Theory, which explain behaviour as an interaction among intention, contextual factors (modes level of service attributes, sociodemographic aspects, trip condition and so on) and habit. Intention would be explained by attitudinal, affective and social factors. In case of the attitude, the expectation-value principle was used, where 5-point Likert scales were utilized to measure these two dimensions. For the affective dimension of intention, the Osgood semantic differential was used, whereas habit was collected using the Verplanken questionnaire.

 

People were interviewed in trains and buses during the morning peak period, in a face to face procedure. A total of 304 surveys were collected, corresponding to 155 women and 149 men. Respondents were students and general people. Average age of respondents was 28 years old, whereas the average monthly personal income (for those working) was 412.000 Chilean pesos (620 USD).

 

Initial modelling has considered the estimation of multinomial logit models, looking for differences between groups, by occupation, age, gender and income. Lexicographic responses on the alternatives were left aside in this first modelling analysis. Preliminary results have shown that people give a high valuation to the transfer time when compared with the in-vehicle travel time, something which is quite relevant when promoting a public transport strategy based on transport modes combination. Waiting time, as it has happened in other studies in the area when using revealed and stated preferences, has resulted non-significant, which could be related to the quite high bus frequencies and the train attainment to itineraries in the study area. Besides, people prefer to transfer in close spaces rather than open air areas, which might affect the space architectural design as well as the investment cost. However, it was not possible to find out the impact of different physical transfer levels on choice, which could be due to the lack of experience of people with respect to this physical design condition in the study area. When comparing between modes, travelling by bus or train-bus was equivalent and worse than combining among railway lines, which could imply that travelling by bus could be a deterrence factor by itself.

 

Interaction between level of service and socio-demographic attributes was also performed. Differences between gender and age was observed after the initial modelling. These differences might be due to different time and budget constraints, affecting attributes valuation.

 

Ongoing work is being developed in order to incorporate in the modelling the psychosocial information about respondents. Previous evidence using revealed preferences has shown that the attitude towards certain aspects, such as transport modes and environmental concern, might lead to a specific behaviour when dealing with mode choice. Besides, the affection and emotional ties associated with a mode might also influence the decision process.

 

Hybrid discrete choice models will be estimated incorporating the psychosocial attributes through a latent variables approach. It is expected to identify the effective role of psychosocial, socio-demography and modes attributes on mode choice, looking for the reduction of endogeneity due to missing variables when estimating these models. These results might allow us knowing which are the factors leading the propensity to use a transport mode which requires a transfer process, and guiding the public policy on this issue. This is relevant since it has been found, in a different context, that the incorporation of these psychosocial attributes into the modelling might imply a different level of demand estimation, affecting the whole transport investment decision making process.


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