1. onderzoeksinstituut Workshop Valorisation of transport models for a sustainable transport Namur 19 December 2005 Travel behaviour survey in Flanders : the latest developments Erik Nuyts Provinciale Hogeschool Limburg

2. onderzoeksinstituut Short History of OVG: Travel Behaviour Survey in Flanders 1993Haalbaarheidsstudie 1995OVG Vlaanderen 1997OVG Kust 1999OVG Antwerpen OVG Hasselt-Genk 2000OVG Vlaanderen 2 OVG Gent 2001(OVG Vlaams-Brabant) OVG Leuven, OVG Mechelen, OVG Aalst OVG Rand rond Brussel

3. onderzoeksinstituut Response Rates

4. onderzoeksinstituut Comparison OVG With Other Studies Time budget survey Mobel Socio-Economic Survey Neu Kontiv Design Dutch OVG Literature

5. onderzoeksinstituut Comparison OVG With Other Studies Mainly methodology Limited comparison of results, trying to recalculate OVG results with Mobel or TBE methodology

6. onderzoeksinstituut Main Results Suggestions for possible changes in methodology

7. onderzoeksinstituut Policy Decision: change wanted ? Do they prefer improvement or comparison between OVG’s

8. onderzoeksinstituut Main Results SAMPLE

9. onderzoeksinstituut Person or household level ? At present: household level household is a relevant entity often many respondents in 1 agreement  household less evident (divorce,..)  more difficult if recruiting by GSM

10. onderzoeksinstituut 1 household or group with 4 back-up households ? At present: 1 household cheaper  non-response results in more bias

11. onderzoeksinstituut Continuous survey or not ? 500 each year or 2500 every 5 year ? Smoother follow-up: every year a 5-year average  Never a full survey of 1 year  Every change in methodology lasts 5 years

12. onderzoeksinstituut Main Results CONTACT PROCEDURE

13. onderzoeksinstituut Incentive or not ? At present: no incentive  lower response rate incentive too expensive compared to expected increase of response rate

14. onderzoeksinstituut Postal contact: ask for phone/GSM At present: not asked Positive reactions according to NKD

15. onderzoeksinstituut First contact: closer to fill-in day At present: – phone call 8-10 days before fill-in day – if Ok, then send diaries Alternative: – send diaries (social pressure) – phone call 1-2 days before fill-in day

16. onderzoeksinstituut Diaries: keep paper en pencil At present: diaries Alternative 1: face-to-face if person level: item response   if household level : overall response   more expensive

17. onderzoeksinstituut Diaries: keep paper en pencil Alternative 2: CATI if person level: item response   if household level : overall response 

18. onderzoeksinstituut Main Results DIARY

19. onderzoeksinstituut 1 or 2 survey days ? At present: 2 survey days  2 nd day biased  too expensive when 1 day is used intra-individual differences

20. onderzoeksinstituut 1 or 2 survey days ? more trips for small groups more trips for multimodal models  not independent  decrease in response… … but not half of response

21. onderzoeksinstituut Proposition: 1 or 2 days If – Budget allowed to increase (= # trips) – Not interested in intra-individual behaviour – Increase of response rate is more important then 1 day survey

22. onderzoeksinstituut 1 or 2 types of questions on work/ school trips ? At present: 1 general question + detailed data in diary information on work / school trips for every respondent more information from trips done…  … but not independent

23. onderzoeksinstituut 1 or 2 types of questions on worktrips ?  Double work for half of respondents intra-individual information  increased burden, decreased response

24. onderzoeksinstituut Proposition: 1 or 2 types of questions on worktrips If – Budget allowed to increase (= # independent data) – Not interested in intra-individual behaviour – Increase of response rate is more important then no general question

25. onderzoeksinstituut Questions on attitudes/opinions or not ? At present: no more attitudes/opinions only facts decrease of answer to social willingness

26. onderzoeksinstituut Keep or skip hardly analysed questions ? At present: detailed questions concerning –Moped, motorcycle,… – type of working contract – full time / part time job – ….

27. onderzoeksinstituut Distance to bus stop, train station: search in external database At present: questions  answer very unreliable

28. onderzoeksinstituut Trips shorter than 100 m: no directives At present: directive: “do not write them down” more room for other trips  suggestion of unimportant trips  burden of decision for respondent

29. onderzoeksinstituut Coding/recoding trips

30. onderzoeksinstituut Coding/recoding trips : keep it Alternative: main transport mode, for details on public transport: survey afterwards (cfr Dutch OVG) Present Flemish OVG: full information multimodal trip  burden for respondent details still remembered

31. onderzoeksinstituut 3 kinds of ‘shopping’ ? at present: shopping smallest burden for respondent  hard to fit in multimodal models

32. onderzoeksinstituut Shopping: a purpose criterium ? Purpose: – weekly necessary grocery purchase – recreational shopping – exceptional purchase Frequency: – ± 1 or 2 per week – ± 1 per month – ± 1 per year

33. onderzoeksinstituut Shopping: see what fits in lay-out In present lay-out: increasing complexity is decreases response If lay-out is changed (price !) then motive shopping reconsidered

34. onderzoeksinstituut Main Results EDITING

35. onderzoeksinstituut Editing: stay conservative At present: replace empty fields only when very sure  Dutch OVG: ± every empty field filled in

36. onderzoeksinstituut Main Results WEIGHTING PROCEDURE

37. onderzoeksinstituut Eduction in weight: if reliable source At present: no education in weight  education most relevant socio- economic variable  no information available about population ? See if ArbeidskrachtenEnquête and Socio-Economic Survey fit

38. onderzoeksinstituut Calculation of weight At present: different calculation of weight in OVG, Mobel, TBE To do: – Try different calculations – Select the one with the smallest St. Dev the smallest range

39. onderzoeksinstituut Main Results NEW TECHNOLOGY

40. onderzoeksinstituut New technology ? At present: paper and pencil accepted by everyone  some prefer internet  no detail on road used

41. onderzoeksinstituut New technology: as an extra  Only internet, PDA,GPS… then bias  internet, PDA,GPS as an extra, then more expensive Wait results of SBO

42. onderzoeksinstituut QUESTIONS ? REMARKS ?