onderzoeksinstituut workshop valorisation of transport models for a sustainable transport namur 19...
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onderzoeksinstituut
Workshop Valorisation of transport models for a sustainable transport
Namur 19 December 2005
Travel behaviour survey in Flanders :
the latest developments
Erik NuytsProvinciale Hogeschool Limburg
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Short History of OVG: Travel Behaviour Survey in Flanders
1993 Haalbaarheidsstudie1995 OVG Vlaanderen1997 OVG Kust1999 OVG Antwerpen
OVG Hasselt-Genk2000 OVG Vlaanderen 2
OVG Gent2001 (OVG Vlaams-Brabant)
OVG Leuven, OVG Mechelen, OVG Aalst OVG Rand rond Brussel
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Response Rates
Response rate Travel Behaviour Surveys
0%10%20%30%40%50%60%70%80%90%
Antwerp
en
Hasse
lt-G
enk
Vlaan
dere
nG
ent
Leuv
en
Mec
hele
nAal
st
Rand
rond
Bru
ssel
OVG N
L
Datel
ine V
laande
ren
Bern
(CH)
Burge
nland
(A)
Cram
lingt
on (U
K)
Lond
on (U
K)
Ludv
ika /
Smed
jebac
ken
(SW
)
Mel
bour
ne (A
US)
Nürnb
erg
(D)
Paris
(F)
Portla
nd (U
SA)
Towns
ville
(AUS)
Wie
n (A
)
Survey
Re
sp
on
se
ra
te
First contact Tel. Only postal contact Total
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Comparison OVG With Other Studies
Time budget survey
Mobel
Socio-Economic Survey
Neu Kontiv Design
Dutch OVG
Literature
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Comparison OVG With Other Studies
Mainly methodology
Limited comparison of results, trying to recalculate OVG results
with Mobel or TBE methodology
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Main Results
Suggestions for possible changes in methodology
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Policy Decision: change wanted ?
Do they prefer
improvementor
comparison between OVG’s
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Main Results
SAMPLE
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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
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households ?At present: 1 household
cheaper
non-response results in more bias
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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
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Main Results
CONTACT PROCEDURE
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Incentive or not ?
At present: no incentive
lower response rate
incentive too expensive compared to expected increase of response rate
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Postal contact: ask for phone/GSM
At present: not asked
Positive reactions according to NKD
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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
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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
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Diaries: keep paper en pencil
Alternative 2: CATI
if person level: item response
if household level : overall response
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Main Results
DIARY
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1 or 2 survey days ?
At present: 2 survey days
2nd day biased
too expensive when 1 day is used
intra-individual differences
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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
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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
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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
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1 or 2 types of questions on worktrips ?
Double work for half of respondents
intra-individual information
increased burden, decreased response
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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
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Questions on attitudes/opinions or not ?
At present: no more attitudes/opinions
only facts
decrease of answer to social willingness
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Keep or skip hardly analysed questions ?
At present: detailed questions concerning
–Moped, motorcycle,…
– type of working contract
– full time / part time job
– ….
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Distance to bus stop, train station: search in external database
At present: questions
answer very unreliable
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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
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Coding/recoding trips
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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
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3 kinds of ‘shopping’ ?
at present: shopping
smallest burden for respondent
hard to fit in multimodal models
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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
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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
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Main Results
EDITING
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Editing: stay conservative
At present: replace empty fields only when very sure
Dutch OVG: ± every empty field filled in
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Main Results
WEIGHTING PROCEDURE
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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
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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
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Main Results
NEW TECHNOLOGY
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New technology ?
At present: paper and pencil
accepted by everyone
some prefer internet
no detail on road used
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New technology: as an extra
Only internet, PDA,GPS… then bias
internet, PDA,GPS as an extra, then more expensive
Wait results of SBO
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QUESTIONS ?
REMARKS ?