Purpose of Survey

The National Travel Survey (NTS) is a household survey on the travel behaviour of respondents. It was conducted in the fourth quarter (October – December) of 2021 as part of the General Household Survey (GHS).

Data from the NTS is used to help monitor the implementation of transport policy and will inform future transport initiatives.

Survey Design

The NTS was carried out as part of the General Household Survey (GHS) for the first time in 2019. The most recent NTS, carried out in Quarter 4 2021, was also carried out using the GHS survey vehicle.

The GHS is a national survey that place takes place three or four times each year. The survey usually has a core of common demographic questions that are always asked (e.g. age, sex, education, etc.). Each survey also has a specific theme. In the fourth quarter of 2019, the GHS covered the National Travel Survey.

Here below are the topics covered in the GHS so far:

Prior to 2019, the NTS was carried out in 2012, 2013, 2014 and 2016 as a module of the Quarterly National Household Survey (QNHS).

Reference Period

The National Travel Survey for the reference year 2021 was included in the GHS in the three months from October to December 2021 (Quarter 4). The travel reference days, i.e. the days for which travel data was collected, covered the period October 4th 2021 – January 9th 2022.

Questionnaire

The NTS questionnaire was designed by the Central Statistics Office in consultation with the Department of Transport, Tourism and Sport (DTTS), the National Transport Authority (NTA) and the Road Safety Authority (RSA).

Up to and including 2016, the survey was carried out as a module of the Quarterly National Household survey (QNHS). The survey was primarily focussed on the travel behaviour of respondents. The information collected included the following:

• number of journeys made
• reason for making each journey
• mode of transport used
• the duration of each journey
• distance travelled

The survey was carried out using the General Household survey (GHS) for the first time in 2019. With the change in the way the survey was carried out, there was greater scope for the inclusion of new topics, including:

• Facilitators and inhibitors to the use of public transport
• Frequency and use of walking and cycling as a mode of transport, and facilitators and inhibitors to these modes of transport
• Electric vehicles
• Road collisions

The 2021 survey was also carried out using the GHS survey vehicle.

A copy of the NTS 2021 questionnaire is available on the CSO website at: National Travel Survey 2021 Questionnaire (PDF 405KB)

Individual Reference Person

This survey was asked of persons aged 18 years and over. One person from each household was selected. Only direct respondents were included in the NTS survey (i.e. no third party responses were permitted).

Data Collection

In 2021, the NTS was carried out using CAWI (Computer Assisted Web Interviewing). Prior to this, the survey data was conducted using a team of face-to-face interviewers using Computer Assisted Personal Interviewing (CAPI).

Response rates for the NTS were impacted by the change of mode to 100% online interview. The achieved sample for the 2021 NTS survey was 3,027, compared with 3,650 in 2019.

Also, in order to adapt the questionnaire for CAWO data collection mode, much care and attention was given to simplifying the questionnaire in so far as possible, in conjunction with the Questionnaire Design Unit in the CSO, especially for persons who might be less familiar with ICT and online questionnaires. Features such as pop up information notes, survey summary side bar and survey block functionality which could be edited at any point in the questionnaire, save and complete later functionality, were just some of the features included to make the questionnaire user friendly and adaptable for any device used.

Survey Coverage

The NTS data is collected directly from persons residing in private households. Institutional households, (e.g. nursing homes, barracks, boarding schools, hotels etc.) are not covered by the survey.

A household is defined as a single person or group of people who usually reside together in the same accommodation and who share the same catering arrangements. The household members are not necessarily related by blood or marriage.

A person is defined as a "Usual Resident" of a private household if he or she:

• Lives regularly at the dwelling in question, and
• Shares the main living accommodation (i.e. kitchen, living room or bathroom) with the other members of the household.

Sample Design

The sample for the General Household Survey (GHS) is stratified using administrative county and the Pobal HP (Haase and Pratschke) Deprivation Index (quintile). A two-stage sample design is used. In the first stage 1,300 blocks are selected using Probability Proportional to Size (PPS) sampling. In the second stage households are selected using Simple Random Sampling (SRS). This ensures each household in the sample frame has an equal probability of selection.

The total sample size for the National Travel Survey in Q4 2021 was 9,600 households. The number of valid responding households was 3,027. Information was collected on 6,752 journeys.

The survey results were weighted to agree with population estimates broken down by age, sex and region and are also calibrated to nationality totals.

Derivation of Results

To provide national population results, the survey results were weighted to represent the entire population of persons aged 18 years and over. The survey results were weighted to agree with population estimates broken down by age group, sex and region and were also calibrated to nationality totals.

Household weights were calculated for all households in the initial sample. The design weights are computed as the inverse of the selection probability of the unit. The purpose of design weights is to eliminate the bias induced by unequal selection probabilities.

These design weights were then adjusted for non-response. This eliminated the bias introduced by discrepancies caused by non-response, particularly critical when the non-responding households are different from the responding ones in respect to some survey variables as this may create substantial bias in the estimates. Design weights are adjusted for non-response by dividing the design weights of each responding unit in the final/achieved sample by the (weighted) response probability of the corresponding group or strata.

To obtain the final household weights for the results, after the previous steps were carried out, the distribution of households by deprivation, NUTS3 region, sex and age was calibrated to the population of households in Quarter 4 2021 (as derived from the LFS Survey). The CALMAR2-macro, developed by INSEE, was used for this purpose.

Note on Tables

The sum of row or column percentages in the tables in this report may not add to 100.0% due to rounding.

Percentage breakdowns exclude cases where the interviewee did not respond.

Disclosure Control

Estimates for number of persons where there are less than 30 persons in a cell are too small to be considered reliable. These estimates are presented with an asterisk (*) in the relevant tables.

Where there are 30-49 persons in a cell, estimates are considered to have a wider margin of error and should be treated with caution. These cells are presented with parentheses [ ].

In the case of rates, these limits apply to the denominator used in generating the rate. In the case of annual changes, both the current year and the preceding year are taken into account when deciding whether the estimate should be suppressed or flagged as having a wider margin of error.

Reliability of Estimates Presented

Data are subject to sampling and other survey errors, which are relatively greater in respect of smaller values.

Key Definitions and Descriptions

Population

This survey was asked of adults, aged 18 years and over, resident in the Republic of Ireland.

Region

The regional classifications in this release is based on the NUTS (Nomenclature of Territorial Units) classification used by Eurostat. Until Q4 2017, the NUTS3 regions corresponded to the eight Regional Authorities established under the Local Government Act, 1991 (Regional Authorities) (Establishment) Order, 1993, which came into operation on 1 January 1994 while the NUTS2 regions, which were proposed by Government and agreed by Eurostat in 1999, were groupings of those historic NUTS3 regions.

However, the NUTS3 boundaries were amended on 21st of November 2016 under Regulation (EC) No. 2066/2016 and have come into force from Q1 2018. These new groupings are reflected in the LFS results from Q1 2012 onwards. The changes resulting from the amendment are that County Louth has moved from the Border to the Mid-East and what was formerly South Tipperary has moved from the South-East to the Mid-West, resulting in the new NUTS2 and NUTS3 regions:

Acknowledgement

The Central Statistics Office wishes to thank the participating households for their co-operation in agreeing to take part in the National Travel Survey and for facilitating the collection of the relevant data.