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

onderzoeksinstituut

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

onderzoeksinstituut

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

onderzoeksinstituut

Comparison OVG With Other Studies

Time budget survey

Mobel

Socio-Economic Survey

Neu Kontiv Design

Dutch OVG

Literature

onderzoeksinstituut

Comparison OVG With Other Studies

Mainly methodology

Limited comparison of results, trying to recalculate OVG results

with Mobel or TBE methodology

onderzoeksinstituut

Main Results

Suggestions for possible changes in methodology

onderzoeksinstituut

Policy Decision: change wanted ?

Do they prefer

improvementor

comparison between OVG’s

onderzoeksinstituut

Main Results

SAMPLE

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

onderzoeksinstituut1 household or group with 4 back-up

households ?At present: 1 household

cheaper

non-response results in more bias

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

onderzoeksinstituut

Main Results

CONTACT PROCEDURE

onderzoeksinstituut

Incentive or not ?

At present: no incentive

lower response rate

incentive too expensive compared to expected increase of response rate

onderzoeksinstituut

Postal contact: ask for phone/GSM

At present: not asked

Positive reactions according to NKD

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

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

onderzoeksinstituut

Diaries: keep paper en pencil

Alternative 2: CATI

if person level: item response

if household level : overall response

onderzoeksinstituut

Main Results

DIARY

onderzoeksinstituut

1 or 2 survey days ?

At present: 2 survey days

2nd day biased

too expensive when 1 day is used

intra-individual differences

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

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

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

onderzoeksinstituut

1 or 2 types of questions on worktrips ?

Double work for half of respondents

intra-individual information

increased burden, decreased response

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

onderzoeksinstituut

Questions on attitudes/opinions or not ?

At present: no more attitudes/opinions

only facts

decrease of answer to social willingness

onderzoeksinstituut

Keep or skip hardly analysed questions ?

At present: detailed questions concerning

–Moped, motorcycle,…

– type of working contract

– full time / part time job

– ….

onderzoeksinstituut

Distance to bus stop, train station: search in external database

At present: questions

answer very unreliable

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

onderzoeksinstituut

Coding/recoding trips

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

onderzoeksinstituut

3 kinds of ‘shopping’ ?

at present: shopping

smallest burden for respondent

hard to fit in multimodal models

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

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

onderzoeksinstituut

Main Results

EDITING

onderzoeksinstituut

Editing: stay conservative

At present: replace empty fields only when very sure

Dutch OVG: ± every empty field filled in

onderzoeksinstituut

Main Results

WEIGHTING PROCEDURE

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

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

onderzoeksinstituut

Main Results

NEW TECHNOLOGY

onderzoeksinstituut

New technology ?

At present: paper and pencil

accepted by everyone

some prefer internet

no detail on road used

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

onderzoeksinstituut

QUESTIONS ?

REMARKS ?