In 2011, DfT conducted a public consultation on possible changes to the National Travel Survey.  This focused on the need to collect data in a more cost-effective manner from the start of a new fieldwork contract in 2013. The proposals covered four areas:
 
• The potential move to adopting the use of Global Positioning System (GPS) devices to collect the personal trip data currently collected via a written seven-day diary.

• Removing groups of relatively lower-value questions from the NTS interview in order to reduce both burden on respondents and cost.

• Reducing the DfT funded geographic coverage of the NTS from a Great Britain sample to England-only, reflecting devolution of transport policy in Scotland and Wales.

• An open invitation for suggestions on wider changes to data collection.

The Department also ran a pilot project to compare results obtained from GPS devices and conventional travel survey forms.

The consultation was conducted with great care, to make sure the views of users were recorded and understood.  The Department acknowledged the concerns of respondents to the consultation with regard to data items lost, particularly travel by persons under 12, escort trips and car driver/passenger modal split. It also recognised the adverse effect a likely break in the NTS time series would have on users.

The Department stated that the findings of the pilot survey did not give it sufficient confidence in the capacity of the GPS approach to identify trip start and end points, and to infer trip mode and purpose, to the level of accuracy required. At a meeting of the Transport Statistics User Group, the Department explained that there were surprisingly large differences in trip rates recorded by the GPS devices and the conventional travel diary.  Three reports on the fieldwork, data processing and summary analysis for the 2011 NTS GPS pilot are all published in the 'future developments' section on the NTS series page of the DfT website, here.  

Furthermore, the Department’s experience of working on this project leads it to conclude that data processing for this methodology is not sufficiently well developed to support a large-scale, continuous National Statistics survey such as the NTS.

The Department has therefore decided that  the data collection method for the NTS from 2013 will remain as a written paper travel diary. It will not use a GPS device.   Some changes to the questionnaire will be made to reduce interview time, and from 2013 the survey will only cover England.

Kit Mitchell from the CIHT Sustainable Transport Panel said "As a user of NTS I welcome these decisions.  The NTS is probably the best long term source of travel data in the world, and the Department is acting to maintain it as such."