National Travel Survey (NTS)

Summary

The NTS is carried out primarily for the purposes of government. It is used to develop consistent sets of transport policies. Because it relates travel to travellers, it makes it possible to relate policies to people and to predict their impact. The survey provides detailed information on different types of travel: origin and destination of journey, distance, purpose and mode. The NTS records personal and socio-economic information to distinguish between different types of people, and the differences in the way they travel and how often they do so. The NTS is the only source of national information on subjects such as cycling and walking, which provides a context for the results of more local studies. The advantage of the continuous study on a three-year cycle is that users will be able to discern seasonal and cyclical movements, as well as trend changes over time. New variables have been introduced at the start of each new three-year period. Changes to the methodology in 2002 mean that there are some inconsistencies with data for previous years. Most notably, an under-recording of short walks in 2002 and 2003 affects trends over this period, particularly in terms of the number of trips per person.

Type of data

Data Source
Survey

Type of Study
Crosssection regular

Data gathering method
Face-to-face
Other: Face-to-face interview; Diaries

Access to data

Conditions of access
Data are available from the UK Data Service (previously the Economic and Social Data Service, ESDS): http://ukdataservice.ac.uk/ The website contains detailed information on conditions of access, and it is also possible to contact the UK Data Service by phone: +44 (0)1206 872143, or by email: help@ukdataservice.ac.uk

Type of available data (e.g. anonymised microdata, aggregated tables, etc.)
Anonymised microdata

Formats available
Survey data from the UK Data Service are usually available to download in SPSS, Stata and tab-delimited (suitable for use in MS Excel) formats.

Coverage

Coverage Years of collection, reference years, and sample sizes
The first NTS was commissioned by the Ministry of Transport in 1965-1966. Further periodic surveys were carried out in 1972-1973, 1975-1976, 1978-1979 and 1985-1986 (the UK Data Archive holds data from 1972 onwards). Since July 1988 the NTS has been carried out as a continuous survey with field work being carried out in every month of the year, and an annual set sample of over 5,000 addresses. From 2002, the NTS sample was increased approximately threefold, to incorporate roughly 16,000 addresses per year. The study was originally released in March 2006 and contained data from 2002-2004. The second edition (August 2008) included updated data and documentation covering 2002-2006. For the third edition (January 2009), the vehicle data file was updated with new variables covering commuting, business, private and annual mileage, and the documentation was also updated. For the fourth edition (February 2010), the depositor supplied a file containing replacement weights for the long distance journey (LDJ) data. The method used to calculate the weight excluding the house component had incorrectly assigned the weight from the previously-processed LDJ where the current LDJ date was missing. Less than 1 per cent of cases had been affected, but the weighting variables W4 and W4xHH have now been replaced with corrected versions. For the fifth edition (June 2010), updated data and documentation to cover 2002-2008 have been added to the dataset. For the sixth edition (January 2012), the data and documentation were updated to extend coverage to 2010. For the seventh edition (April 2012), variables h85sis and h85sds in the household file were replaced, as the previous versions of these variables had included incorrect coding. Number of units sampled in recent surveys: 7,437 households in 2002; 8,258 households in 2003; 8,122 households in 2004; 8,430 households in 2005; 8,297 households in 2006; 8,431 households in 2007; 8,094 households in 2008, 8,384 households in 2009 and 8,097 households in 2010. `Note: Older people are represented in this data source (approximately) according to their proportion in the population. In 2011, over one third of the total UK population (and approximately 40 per cent of the adult population 16+) was aged 50 and over.`

First year of collection
2002 (2002 with the large sample; 1988 for continuous survey; 1965 for oldest data regardless of design)

Stratification if applicable
The data includes a variety of demographic variables, including age and sex. The sample is stratified.

Base used for sampling

Geographical coverage and breakdowns
Countries (England, Wales, Scotland) Government Office Regions (NUTS1)

Age range
All ages

Statistical representativeness
Other, please specify

Coverage of main and cross-cutting topics
The National Travel Survey (NTS) is a series of household surveys designed to provide regular, up-to-date data on personal travel and monitor changes in travel behaviour over time. The original main objectives of the survey are: • to estimate the distribution of car ownership and the variation in car utilisation, and their dependence on demographic, socio-economic and other factors • to determine personal and household travel generation rates and the relationship between these rates and a wide range of demographic, socio-economic and other variables • to provide data affording an examination of the modal split for journeys of different types, to determine in what ways and under what circumstances public transport is competitive with the private sector • to provide information to fill gaps in national transport data derived from other sources; for example, taxi and car hire usage, ownership and usage of two-wheeled vehicles, and the distribution of expenditure between private and business travel The 2002-2010 NTS includes: • household variables: address type information, accessibility of public transport, access to amenities, household vehicle access, household composition and household socio-economic information • individual information: age, gender and marital status, social and economic information, frequency of use of various methods of transport, driving licences and type of vehicle driven, employment, occupation and industry details, income, place of work and travel to work, travel benefits connected with work, season ticket details, travel difficulties, any LDJs made, LDJ information, playing in the street (for children) • vehicle information: vehicle type, registration details, parking, vehicle subsidies, mileage, fuel used and purchased, non-eligible travel • trips: day, date and time, main mode, purpose, origin and destination information • stage: mode, number in party, distance, costs • long-distance trips (over 50 miles): stage: mode, purpose, origin and destination

Linkage

Standardisation
There is an ongoing cross-governmental programme of work in the UK which aims to develop and improve standardised inputs and outputs for use in official statistics. This is known as harmonisation, and is led by the Office for National Statistics (ONS). While this work primarily affects government-run surveys, the results have an impact on most national UK data sources. Furthermore, harmonisation has important benefits for all researchers using these surveys, and not just government statisticians. For more information, see: http://www.ons.gov.uk/ons/guide-method/harmonisation/harmonisation-index-page/index.html

Possibility of linkage among databases
Data are anonymised

Data quality

Entry errors if applicable
In addition to unit non-response, the data include item non-response and may be subject to other errors that are typical of surveys and censuses. This data source is used to prepare official statistics, which are required to meet quality standards. These standards are monitored by the UK Statistics Authority, according to the statutory authority provided by the Statistics and Registration Service Act 2007. http://www.statisticsauthority.gov.uk/national-statistician/producers-of-official-statistics/index.html http://www.statisticsauthority.gov.uk/national-statistician/types-of-official-statistics/index.html For more information on data quality, see the survey documentation on the UK Data Service website.

Breaks
There are some breaks for this data source (see the section on Coverage). For example, changes to the methodology in 2002 mean that there are some inconsistencies with data for previous years. Most notably, an under-recording of short walks in 2002 and 2003 affects trends over this period, particularly in terms of the number of trips per person.

Consistency of terminology or coding used during collection
In general, the consistency of this data source is good. For more information on data quality, see the survey documentation on the UK Data Service website.

Governance

Contact information
Department for Transport (DfT)
Great Minster House
33 Horseferry Road
SW1P 4DR London United Kingdom Phone: +44 (0)207 944 3097
Email: national.travelsurvey(at)dft.gsi.gov.uk
Url: http://ukdataservice.ac.uk/

Timeliness, transparency
Data are available about 15 months after the end of fieldwork