Mobility trend Dutch national travel surveys 1999-2020

What does the Mobility trend comprise?

Purpose

To compile statistical information on the daily mobility of the Dutch population for the benefit of the Ministry of Infrastructure and Water Management, other policy and research organisations, Dutch society and Statistics Netherlands (CBS) itself. This entails a description of developments in the travel behaviour of the Dutch population, by place of origin and destination, time of transport, modes of transport used and travel purposes. In addition, ample attention is being paid to background variables for mobility patterns and choices of modes of transport. The aim of the trend series is to estimate sequentially comparable data based on stage information from successive travel studies (which are not comparable to each other).

Target population

The Dutch population living in private households, i.e. excluding institutional residents.

Statistical unit

Person, stage

Date/year survey started

The trend estimates have been calculated with data from four successive National travel surveys named: Onderzoek Verplaatsingsgedrag (OVG; 1999-2003), Mobiliteitsonderzoek Nederland (MON; 2004-2009), Onderzoek Verplaatsingen in Nederland (OViN); 2010-2017 and the still ongoing mobility survey Onderweg in Nederland (ODiN); 2018-. All these successive studies have changed significantly in various respects compared to the previous investigation. Therefore, they are not sequentially comparable. In order to enable sequential comparisons for part of the mobility variables at stage level, trends for the period 1999-2020 have been estimated using renewed time series models.

Frequency

The trend series is supplemented and recalculated once every year to every 2 years.

Publication strategy

Published annually over a completed calendar year. These are provisional figures.

How is the survey conducted ?

Survey type

The estimates of the mobility trend are based on successive mobility studies.
The OVG (1999-2003) and the MON (2004-2009) were carried out as household surveys, the OViN (2010–2017) and the ODiN (2018-2020) as personal surveys.

Survey method

For the estimates of the trend series, the data from successive mobility surveys were used as a source. The methods of observation of these surveys have changed over time. The OVG, which has been renewed since 1999, and also the MON consisted of a relatively simple written survey with telephone motivation from (telephone accessible) respondents with any follow-up surveys for more detailed information. The observation method of OViN (2010-2017) was mixed-mode. Sampled persons were asked by letter to complete the OViN questionnaire via the internet (CAWI). If people did not want to or could not respond via the internet, the telephone (CATI) approach followed if the telephone number was known to CBS, otherwise the questionnaire was taken at the research person's home (CAPI). The ongoing ODiN has only been observed via an internet questionnaire and only for persons aged 6 years or older. In this study, too, persons were asked in advance by letter to complete the ODiN questionnaire via the internet (CAWI only).

Respondents

Respondents (reporters) are all persons from Dutch households (OVG, MON), or from individuals (OViN, ODiN). Residents of institutions and homes are not included in the sample. Contrary to previous mobility surveys, the respondents to the ODiN survey consist of persons aged 6 years or older.

Sample size

For the trend estimates, data from OVG, MON, OViN and ODiN were used. The sample at OVG and MON consists of the national survey. At OViN and ODiN, the national survey has been supplemented with any additional research(s). In the survey description of OVG and MON and also of OViN and ODiN (see Relevant links) sample size and response rate are mentioned.

Weighting

Information about the travel behaviour is collected from all respondents on one particular day of the year. In order to provide reliable statements over the whole year and about the entire Dutch population except institutional residents and with respect to the ODiN survey also excluding the population younger than 6 years, the sampling results must be extrapolated. To this end, weighting factors are calculated with a weighting according to background characteristics, which also corrects the selectivity in the sample. The background characteristics included in the weighting are characteristics relevant to travel behaviour, such as age, gender, income, urbanity and vehicle ownership.
In addition, a correction and estimation has been made for each study in order to map inland mobility. For more information about the weighting per study, see Relevant links. For more information about the time series modeling please also see Relevant links.

Grossing up

The results of the survey are 'translated' into population numbers. This is done by using the weighting factors in the database in the analyses to calculate the results.

Quality of the results

Accuracy

When the trend series was established, the values at stage level in the StatLine table with the Mobility Trend were reassessed and new inaccuracy margins were calculated. In sample research, such as OVG, MON, OViN and ODiN, information was only collected from a part of the population. The estimated results based on the sample data are generally not equal to the actual values and thus have margins of inaccuracy.

Sequential comparability

The data in the trend series (1999-2020) are comparable in a sequential way.