Overcoming the Design and Fieldwork Challenges for Modelling the Choice of Mode of Travel to the Isles of Scilly

Overcoming the Design and Fieldwork Challenges for Modelling the Choice of Mode of Travel to the Isles of Scilly


Peter Burge, Charlene Rohr, Stephen Miller, RAND Europe, UK; Marco Kouwenhoven, RAND Europe, NL; Rachel Risely, Accent, UK


We provide an overview of the approach used to understand choices made when travelling to and from the Isles of Scilly. We focus on the design of the surveys and challenges in conducting the fieldwork and draw transferable lessons for future studies


The Isles of Scilly are located 28 miles off the south west coast of England. The Isles comprise of five inhabited islands, with a combined population of about 2000, and many smaller uninhabited islands and rocky islets. The main industry on the Isles is tourism, which is highly dependent upon the transport links to and from the mainland.

At present there are three commercial services operating between the Isles and the mainland: a sea ferry, a helicopter service and fixed-wing aircraft services. However, the boat used for the ferry service is now nearing the end of its operational life and if nothing is done, the sea ferry will be taken out of service after 2014.

Cornwall County Council submitted a bid to the UK Department for Transport for capital funding support for improved transport links between the Isles of Scilly and the mainland. Within this bid a number of different investment schemes were developed to replace the current ferry with a new (and possibly faster) one as early as 2009. To support this bid, the Cost Benefit Assessment (CBA) for these investment schemes required predictions of travellers? demand and mode shares to be made. A model of travellers? mode choice between ferry, helicopter and fixed wing aircraft was therefore required.

This paper reports on the research undertaken to provide the data necessary to estimate the model of mode choice. In order to be able to estimate a robust model, it was first necessary to obtain a better understanding of what is driving the current decisions that travellers (both tourists and residents) make when choosing between the services available. This was complemented with research into the decisions that they may make in the future when the ferry service differs from now, exploring variables such as: the number and time of sailings, the speed of the crossing, the comfort of the boat, and the facilities available at the quaysides. The research also explored the choices that would be made if a ferry service no longer operated.

The nature of the travel being undertaken posed some significant challenges, such as the diversity of the journey origins (or destinations in the case of islanders travelling to the mainland) and the wide range of variation in the associated time spent in access modes prior to the short hop over to the islands. In addition, although the available modes for the journey to and from the islands are restricted, there is a wide range of fares available for these modes, resulting in a large number of alternatives for the traveller to chose between.

The paper is intended to provide the reader with an overview of the approach used in designing the research instruments and the challenges faced in conducting the fieldwork. The transferable lessons provide useful guidance to those designing future exercises to collect data for demand and mode choice models for islands and tourism destinations.


Association for European Transport