Migrating from Trip-based Models to Activity-based Models- Introducing a Conceptual Modelling Framework
S Khorgami, SKM Colin Buchanan, UK
This paper introduces a framework that can be recognised as a migration process from a trip based model to an activity based model without imposing the cost of extra data collection at initial steps of model development.
Activity-based travel analysis has received much attention in academic literature and has seen several practical applications in recent decades. Operational models have been developed and are being used in North America and some mainland European cities for policy analysis; although in the UK the practical application of activity-based modelling is much more limited, despite the fact that available sources of travel data enable such models to be developed. One of the main motivations for the development of activity-based models is to provide a model that is sensitive to more comprehensive policy measures than trip-based models (e.g. congestion charging, parking policies, smarter choice, and mixed land use developments).
While activity-based models may improve upon some of the limitations of conventional models and offer new capabilities, there are also questions regarding their theoretical assumptions and whether the benefits promised by these models can be realised in practice. Also, the cost of developing activity based models could be higher than trip based models as the result of data needs and number of model elements which need to be developed, calibrated and validated.
This paper identifies the key concepts behind an activity-based approach and potential applications. Then, it provides a concise summary of important design features of various activity-based model systems that have been implemented or have recently been designed in practice. The types of policy that can be tested by these models are discussed. This will be followed by introducing a modelling framework that can be used to develop an activity-based model using existing travel and land use data. The model framework allows the testing of policies related to land use developments, parking and road pricing. The paper assesses to what extent the activity-based demand modelling concept can successfully be implemented by using the introduced modelling framework. The introduced framework can be recognised as a migration process from a trip based model to a full activity based model without imposing the cost of extra data collection at initial steps of model development.
Finally, the paper discusses the results of recently developed model which outputs daily activity/travel patterns, using individual daily activities as the starting point. The model has two major sequential components: (1) an activity generation and household allocation model system, followed by (2) an activity/travel scheduling model system.
Association for European Transport