Posts from 2017

Peter Davidson presents at the IPENZ conference in Hamilton NZ

I was very fortunate to be sent to the IPENZ Conference in Hamilton NZ courtesy of the AITPM as part of the prize for winning the 2016 Excellence Award. While I was there I presented two papers - one on modelling Autonomous Vehicles and one with an overview of the 4S model with a particular application to New Zealand.

Peter Davidson presents at AITPM Half-day modelling seminar in Brisbane

I will be presenting at the AITPM half-day modelling seminar in Brisbane this week on the topic Rethinking destination choice, accessibility and the reasons for travel.

It has long been recognised that transport is a derived demand - people generally travel because they want to partake in activities at other places, not because they enjoy the travel itself. Given this it is somewhat strange that the benefits of travel do not generally appear in our models, at least not explicitly. Instead, most models focus on cost - the benefits are hidden in core assumptions made in the model structure, particularly in the destination choice model. In this presentation we will explore some of the approaches that have been used for modelling destination choice, including gravity models, intervening opportunity models, entropy maximising models, and random utility models (particularly the logit model). We will see how each of these models makes implicit assumptions about the utility of travel. These assumptions will be critiqued, and we will consider what assumptions may be improved. We will look at how destination choice is handled in TransPosition's 4S model, and how an explicit formulation increases flexibility, allows the use of new data, and gives a richer set of model outputs. Finally we will review the concept of accessibility, and how assumptions about destination utility are critical for a realistic measurement of accessibility and user benefits.

The powerpoint presentation is available here.