DATELINE 

Design and Application of a Travel Survey for Long-distance Trips Based 

on an International Network of Expertise 

– 

Concept and Methodology 

Werner Brög, Erhard Erl & Brian Schulze 

Socialdata – Institute for Transport and Infrastructure Research 

Hans-Grässel-Weg 1, 81375 Munich, Germany / E-mail: socialdata@socialdata.de 

1. Introduction 

Conceived in April 2000 as part of the European Commission’s Competitive and Sustainable Growth program embedded in 

the 5th Framework Program, DATELINE (Design and Application of a Travel Survey for European Long-distance Trips Based 

on an International Network of Expertise) is concerned with European long-distance travel. A specifically designed survey 

was carried out in the 15 Member States of the European Union (EU) and in Switzerland, following a carefully devised 

methodology that had the aim to create one single harmonized long-distance travel database covering all 16 countries. The 

project was funded by the European Commission (EC) and executed by an interdisciplinary research team of twelve 

experienced consortium partners from various parts of Europe. Within the consortium, a combination of competencies from 

the field of theoretical and applied transportation and social market research came together to meet the challenge. 

This paper sets out to describe concepts, methodology and the survey design developed during the first year of the project. It 

also includes a sketch concerning implementation. Information on sampling1

, weighting2 and analysis3 are available through 

the project web site at: http://cgi.fg.uni-mb.si/elmis. General long-distance mobility results derived from the analysis are currently 

being reviewed. Once the EC gives its official seal of approval, they will also be accessible through the site, including the 

possibility to download the complete database for personal use, free of charge.4 

2. Methodology 

Before going into the details of the methodological aspects behind the survey, it is necessary to say something about the 

objectives of DATELINE so as to be able to better understand the choices made by the consortium.5 

2.1 Objectives and Principles 

The overriding goal of the project was to systematically survey long-distance journeys made mainly within the EU, but also 

beyond. Four main objectives formed the framework, which helped the project reach its goal. These were, 

 

1 The total net sample size of the survey was about 85,000 persons. Full documentation of the sampling methodology can be found in 

Deliverable 3 “Sampling Methodology”. It is available for download on the project web site. 

2 Full documentation of the weighting process can be found in Deliverable 10b “Weighting and Grossing-Up”. It is available for download 

on the project web site. 

3 Full documentation of the analysis process can be found in Deliverable 7 “Data Analysis and Macro Results”. It is available for download 

on the project web site. 

4 The web site not only contains project reports and the database, it also offers the possibility to conduct online analyses. A tool specifically 

designed for this task was developed by NESSTAR and modified by the DATELINE Consortium to meet its needs. 

5 Full documentation of the DATELINE methodology can be found in Deliverable 2 “Final Survey Design”. It is available for download on 

the project web site. 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(1) to design a complete survey for European long-distance travel; 

(2) to implement this survey in all 15 EU Member States; 

(3) to build up a valid long-distance mobility database; 

(4) to integrate this database into the EUROSTAT statistical program. 

These objectives did not stand by themselves. They came with four guiding principles, which guaranteed a survey of high 

quality. These principles were, 

(1) to develop a respondent friendly questionnaire; 

(2) to devise a flexible methodology; 

(3) to create a valid database; 

(4) to harmonize all the collected data. 

The first principle aimed at the design of a questionnaire that does not inundate the respondent with unnecessary information 

and confusing definitions. It was made a priority by the consortium to meet the respondent not only half way, but to actively 

unburden him as much as possible. 

The second principle related to the fact that the survey involved many different countries with distinctive cultures and needs. 

Survey traditions differ across Europe, so that precautions had to be taken that would allow the use of survey methods and 

procedures appropriate to the country or region concerned. 

The third principle ensured that collected data was checked for consistency, completeness and plausibility. An additional 

validation survey searching for any travel information that may have been missed was carried out to verify and enhance data 

quality. 

And finally the fourth principle; one may say that it formed the pinnacle of the project work in that all collected and analyzed 

data, regardless of its origin, had to be comparable in order to be of use to future European planning efforts. 

All eight items – objectives and principles – were critical to the success of the project and had to be acknowledged and strictly 

adhered to by all members of the consortium and their affiliates, i.e., subcontractors. 

But not only that. A number of definitions, some of which had already been used by EUROSTAT in previous long-distance 

surveys, were formulated to contribute to the building of a solid foundation for the survey design. These definitions are 

discussed in the next section. 

2.2 Concept and Definitions 

It is impossible to construct a harmonized database without maintaining consistency in the empirical phase of a project. To 

obtain consistency, it is imperative for project participants to reach consensus on the main issues during the conceptual phase. 

Notions about basic mobility concepts such as journey and trip often differ between survey organizations and their experts, 

depending on the traditions and philosophies advocated. So for DATELINE a minimal set of definitions had to be found to 

which all participants could agree. 

The first step was to find the appropriate cut-off distance separating the shorter from the longer journeys. A minimum 

distance of 100 km (crow-fly) to the farthest destination was imposed by the European Commission. This means that all 

journeys of 100 or more kilometers (one-way) qualified as long-distance travel. Compared to other common definitions for 

long-distance travel, the crow-fly distance applied in DATELINE was quite rigid. 

The next step was to be clear on concepts of long-distance journeys and trips. The following definitions were used: 

(1) A journey is a series of trips starting and ending at home or a temporary location. Journeys that include a destination 

more than 100 km (crow-fly) away from the reference location are long-distance journeys. Journeys can consist of many 

trips. 

(2) A trip connects two activities. Trips can begin and end at any location (home city, overnight location, temporary stop). 

Thirdly, a working classification of journey types had to be found, as people travel for many different reasons and thus 

behave in a certain way. In order to facilitate subsequent analysis and also to reduce the burden on the respondent, four 

journey types were distinguished. 
 

 

 

 

 

 

 

 

 

 

(1) Holiday Journey: a journey that lasts for four or more days and is made for holiday purposes. 

(2) Other Private Journey: a journey made for any reason but holiday or business, the exception being a short holiday lasting 

for up to three days. 

(3) Business Journey: a journey made for business purposes. Professional travel undertaken by pilots, truck drivers and the 

like are excluded. 

(4) Commuter Journey: a journey regularly made to or from work / school / university. It includes daily and weekend 

commuters. 

But a classification into journey types alone was not enough. It is a well-known fact among travel specialists that people 

behave differently depending on not only the distance of a journey but also its duration. For this reason a second classification 

was needed. For DATELINE journeys were broken down into one-day and multi-day journeys (see Figures 2.1 and 2.2). 

(1) A one-day journey is defined by the trip to and from the farthest destination, including main stops on the way and major 

changes of transport modes. The return trip may end at any location. 

(2) With respect to multi-day journeys, a trip begins at a reference location (home city, overnight stay or temporary location) 

and ends with the next overnight stay. It includes main stops on the way and major changes of transport modes. Each 

overnight stay of a multi-day journey can mark the beginning of a one-day excursion, which is defined by the trip to the 

farthest destination from an overnight stay and back, including any intermediate stops on the way. 

Figure 2.1 One-Day Journey 

A B 

D 

H 

D 

M H 

A journey with a final destination A journey with a final destination and a 

main stop on the way 

H = Home D = Final destination M = Main stop on the way 

Figure 2.2 Multi-Day Journey 

C D 

E 

O0 

H 

E 

O2 O3 

O1 H 

A journey with one overnight stay and 

a one-day excursion 

A journey with multiple overnight stays 

and a one-day excursion

 H = Home O0 = Overnight stay E = One-day excursion 

2.3 Survey Design 

Concepts and definitions only formed the basis of the survey system. In order to make it complete, a survey design had to be 

developed that would take account of other important aspects such as survey method, unit, timeframe, reporting period, etc., 

all of which have an influence on the final mobility results. 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2.3.1 Methodological Considerations. The first consideration related to the second principle – “flexibility”. National 

peculiarities and the prevailing cultural context called for concessions to individual survey organizations. Years of practical 

experience and intimate knowledge of their own country necessitated a flexibility concerning the choice of the most suitable 

survey method and unit. In the end, three different methods were employed in the survey – postal, telephone and face-to-face. 

The latter two methods mainly used “person” as the survey unit whereas the postal method always addressed the entire 

household. 

The second consideration pertained to the length of time the survey should cover. In order to avoid any seasonal impact, the 

survey was carried out over a total of twelve consecutive months. This means that for each month a new sample was drawn. 

Thirdly, a closely defined system of regular motivations and reminders was built into the survey design, bringing a number of 

advantages. It enabled the field personnel to offer additional advice to the respondent, clarify any misunderstandings that may 

exist or retrieve missing information. The effect was twofold; first, data quality improved and second, the response rate 

increased. 

Finally, thought had to be given to the appropriate reference frame for journeys. Due to the fact that journey classification has 

to do with the character of a journey (some journeys tend to be forgotten more easily than others – “recall effect”), different 

reporting frames or periods were in order. Drawing from previous EU projects such as MEST (Mest Consortium, 1999), the 

following reporting periods were assigned retrospectively: 

(1) Holiday Journeys: twelve months 

(2) Other Private Journeys: three months 

(3) Business Journeys: three months 

2.3.2 A Two-Phase-System. The idea goes back to the first DATELINE principle – respondent friendliness. One essential 

aspect often overlooked in surveys is that the respondent is the “customer” and that he needs to be treated accordingly. This 

means that the burden placed on him by the survey needs to be kept to a minimum level. It was predominantly this reason 

which led the project consortium to the decision to carry out the survey in two separate phases (see Figure 2.3). In Phase 1, 

respondents were asked to report general travel information. Phase 2 then proceeded concentrating only on journeys of special 

interest, so that the majority of respondents were spared from further contact. It should be noted, however, that in the 

telephone and face-to-face surveys both phases were made in just one phase with instantaneous journey selection and 

instantaneous geocoding (if CATI was used). 

The split also brought other important advantages with it. In Phase 2, a person could be addressed personally, journeys could 

be selected using a predefined rule permitting an over-sampling of longer long-distance journeys, one could focus on rarer 

modes and the overall response rate increased. 

Figure 2.3 Survey Concept 

Journey selection 

Phase 2 

Trip level 

Phase 1 

Journey level 

POSTAL TELEPHONE / 

FACE-TO-FACE 

Journey selection 

Phase 2 

Trip level 

Phase 1 

Journey level 

 

2.3.2.1 Phase 1: Journey Level. Phase 1 asked for socioeconomic background information about the household (e.g. number 

of persons in the household, age, gender, employment status). It then continued capturing basic travel data for the main three 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

journey types, including origin and destination, duration, number of participants, journey date etc.. At this point, commuter 

journeys were only registered with regard to their travel distance. 

The number of journeys to be reported in the postal survey was limited to three in the case of holiday journeys and six if the 

journey fell into the other two main categories. For practical reasons, the limit for the latter two categories was lowered to 

five journeys in the telephone / face-to-face surveys. 

2.3.2.2 Phase 2: Trip Level. Phase 2 was more complicated. The idea was to obtain additional information about the 

journeys reported in Phase 1 without overwhelming the respondent. Most journeys have a simple make-up (one destination, 

two trips) and were not worth being inspected further as no new information would be revealed. Thus, journeys that were 

more complex and interesting in terms of long-distance travel were selected using a special rule. 

The rule clearly shows that journeys with specific characteristics took priority over others. The first priority was to make sure 

all journey types are covered. The second priority was given to “long journeys” (more than 500 km), and last but not least, the 

third priority went to time, i.e., journeys were selected in chronological order, beginning with the most recent. 

Just as was done in Phase 1, an upper limit of journeys was fixed to reduce the burden on the respondent. In the postal survey 

the limit was set to six journeys, in the telephone and face-to-face survey it was four. 

However, the rule by itself did not pay respect to the complexities of certain journeys. Therefore, a set of additional criteria 

had to be found and applied in combination with the rule. Using these criteria together with the established rule, it was 

possible to make the appropriate selection of journeys. These criteria are listed below: 

(1) To qualify for selection, a journey had to have been made within Europe. 

(2) It had to be a multi-day journey, or 

(3) If a one-day journey, it had to have been made with at least two different modes of transport or have one additional 

destination 

2.4 The Questionnaire 

In order to accommodate the methodological considerations, the questionnaire developed for the two-phase survey system 

was divided into individual forms (see Figure 2.5). The scheme below shows the relation between these forms and to which 

phase they belong. All forms of the questionnaire were translated into eleven different languages and were used with all three 

methods. Some minor adjustments had to be made in order to make the questionnaire suitable to the employed method as well 

as the surveyed country or region. 

Figure 2.5 The Questionnaire 

Multi-Day Journey 

Form 

Commuting Journey 

Form 

Business Journey 

Form 

One-Day Multi 

Destination Form 

Household + Person Form 

Holiday Journey 

Form 

Other Private Journey 

Form 

One-Day Excursion 

Form 

P 

H 

A 

S 

E 

1 

P 

H 

A 

S 

E 

2 
 

 

 

 

 

 

 

3. Survey Implementation 

The survey was carried out by a number of different institutions. Not only private survey organizations, but also national 

statistical offices and transport ministries were involved.6 

After twelve months of intensive fieldwork in each of the 16 countries, one can say that the implementation of the survey 

system was successful. The overview of response rates in Table 3.1 confirms this assertion. Both phases managed to produce 

an average rate exceeding 65%, which leads to two conclusions: 

(1) Respondents were interested in the subject matter; and 

(2) Respondents were receptive to the survey design and the questionnaire 

The average response rate for Phase 1 across all 16 countries was 66%, which is higher than was expected at the beginning of 

the project. Even in countries such as Great Britain, where postal surveys are generally regarded as being ineffective, a highly 

satisfactory rate was reached. 

Phase 2 fared even better. With an average response rate of 85%, the positive advantage of using a two-phase-system became 

more apparent. 

Table 3.1 Survey Results 

Country 

Austria 

Method 

Postal 

Net Sample 

(persons) 

2,305 

Response Rate Response Rate 

Phase 1 (%) Phase 2 (%) 

 68 79 

Belgium (Flanders) Postal 1,023 80 87 

Belgium (Wallonia +Brussels) Telephone 1,255 41 100 

Denmark Telephone 1,595 73 100 

Finland Telephone 1,797 75 100 

France Telephone 7,379 55 100 

Germany Postal 18,613 70 82 

Great Britain Postal 8,465 63 84 

Greece Telephone 2,993 60 100 

Ireland, Re publicof Telephone 794 77 99 

Italy Postal 11,183 46 44 

Luxembourg Telephone 549 82 100 

Netherlands Postal 7,460 69 82 

Northern Ireland Telephone 592 74 99 

Portugal Face-to-face 5,501 76 100 

Spain Telephone 12,320 81 100 

Sweden Postal 2,427 71 83 

Switzerland 

TOTAL 

Telephone 

-

718 

86.969 

65 100 

66 85 

 

 

 

 

 

 

 

4. Conclusion 

After three years of preparation, co-ordination and implementation, the first collective attempt of a long-distance mobility 

survey for the whole EU has come to an end. The effectiveness of the survey system proved high as indicated by an overall 

response rate of 66% across all 16 countries. People showed much interest in the subject matter and were overwhelmingly 

satisfied with the survey. 

The project has shown that it is possible to develop and implement a long-distance travel survey standard that satisfies distinct 

cultural and institutional needs of the different countries in Europe. Predicated on a critical project analysis, the rich reservoir 

of accumulated experience will allow to establish a permanent European monitoring system for high quality long-distance 

travel surveys. 

6 Full documentation of the implementation process can be found in Deliverable 5 “Final Report on Data Collection”. It is available for 

download on the project web site. 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Once the Commission approves the DATELINE mobility results, it is left to be seen how they compare to other long-distance 

surveys in Europe and the rest of the world. In particular, the EC and National Transport Ministries and Statistical Offices 

will be interested in the data, which will play its role in the formulation of future European transport policy. 

Even though DATELINE merely represents the beginning of a series of collaborative efforts to bring about harmonization, it 

has already contributed inevitably to the shaping of a sustainable future for Europe and possibly the world. Already in the 

making, ideas are being exchanged as to the possibility of a Euro-American collaboration on long-distance travel. 

References 

Dateline Consortium (2001) Deliverable 3: Sampling methodology, Project Report, Brussels, European Commission. 

Dateline Consortium (2002) Deliverable 5: Final report on data collection, Project Report, Brussels: European Commission. 

Dateline Consortium (2002) Deliverable 6: European coding book, Project Report, Brussels, European Commission. 

Mest Consortium (1999) Methods for European surveys of travel behaviour, Project Report, Brussels, European Commission. 

Socialdata und Tis.pt (2003) Long-distance travel in Europe: final results from surveys in the member states, handout paper, 

EUROSTAT Passenger Mobility Working Group Meeting, Luxembourg, April 2003. 

Test Consortium (2000) Technologies for European surveys of travel behaviour, Project Report, Brussels, European 

Commission. 

Keywords 

Broeg, Erl, Schulze, Dateline, travel, long-distance, survey, design, data quality, behaviour, transport, passenger, mobility, 

Europe, FCSM, Research conference 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Annex I The Consortium 

Project Co-ordinator: 

SOCIALDATA – Institut für 

Verkehrs- und Infrastrukturforschung 

GmbH 

Postfach 70 16 29 

D – 81316 München 

GERMANY 

E-mail: dateline@socialdata.de 

Project Participants: 

Universitaet für Bodenkultur, Wien 

Institute for Transport Studies 

Peter Jordan Str. 82 

A – 1190 Wien 

AUSTRIA 

E-mail: dateline@mail.boku.ac.at 

Statistics Netherlands 

Kloosterweg 1, P.O. Box 4481 

NL – 6401 CZ Heerlen 

NETHERLANDS 

E-mail: hbns@cbs.nl 

Helsinki University of Technology, 

Transportation Engineering 

Rakentajanaukio4a, 

P.O. Box 2100 

FIN – 02015 HUT, Espoo 

FINLAND 

E-mail: nina.karasmaa@hut.fi 

Ministry of Transport, AVV 

Transport Research Centre 

Boompjes 200, P.O. Box 1031 

NL – 3000 BA Rotterdam 

THE NETHERLANDS 

E-mail: 

h.c.vevert@avv.rws.minvenw.nl 

Peter Davidson Consultancy 

Brownlow House 

Raven’s Lane 

UK – Berkhamsted Herts. 

HP4 2DX 

UNITED KINGDOM 

E-mail: mail@peter-davidson.com 

POLIEDRA – Politecnico di Milano, Centre 

in Environmental Economics and 

Management 

Via Fucini 2 

I – 20133 Milano 

ITALY 

E-mail: diguardo@poliedra.polimi.it 

Institut Socialdata i Sverige AB 

Kungsgatan 47 A 

S – 75321 Uppsala 

SWEDEN 

E-mail: christine@socialdata.se 

TIS.PT Transportes, Inovação e Sistemas 

Av.5 de Outubro 

N

o

75 – 70 

P – 1050 Lisboa 

PORTUGAL 

E-mail: faustino.gomes@tis.pt 

TRIAS SA 

39 G.Seferi Str. 

GR – 54250 Thessaloniki 

GREECE 

E-mail: dateline@trias.gr 

University of Newcastle upon Tyne, 

Transport Operations Research Group 

Claremont Tower, 

Claremont Road 

Newcastle Upon Tyne, NE1 7RU 

UNITED KINGDOM 

E-mail: neil.thorpe@ncl.ac.uk 

University of Maribor, Civil 

Engineering Informatics Centre 

Smetanova 17 

SLO – 2000 Maribor 

SLOVENIA 

E-mail: nenad@computer.org 

Eidgenössische Technische 

Hochschule Zürich, IVT 

ETH (Hönggerberg) 

CH – 8093 Zürich 

SWITZERLAND 

E-mail: axhausen@ivt.baug.ethz.ch