Applying an Activity-based Travel Diary Compared to a Trip-based Travel Diary in both a Central and an Outlying zone in Madrid. UPM Esther Madrigal Díez Andrés Monzón de Cáceres. NATIONAL LEVEL. Who is providing travel statistics in Spain. PUBLIC WORKS MINISTRY National Household
Compared to a Trip-based Travel Diary in both a
Central and an Outlying zone in Madrid
Esther Madrigal Díez
Andrés Monzón de Cáceres
PUBLIC WORKS MINISTRY
INSTITUTE OF STATISTICS
Time Use survey, 2002-2003
17 regions in Spain
Mobility surveys for the whole region and for the cities in it
Each regions follows its own methodology
In all of them very low
mobility rate (rearely above 2,6 )
Different methodologies mean no comparable results. Yet the range of values should be the same.
Two reasons for this values either this value is just a reflection of reality and, in Spain, mobility is much lower than in the countries taken as reference, or there are some methodological differences that are underestimating the trip rates.
Trip definition, disregards
trips on foot under ten minutes
for national household travel survey
and under five minutes for local surveys
Type of survey diary
Both diaries were arranged in two parts:
1) Socioeconomic questionnaire (same for both). One member of the household provide information about each of it members
2) Mobility questionnaire: each member of the household provide information about his own travel movements.
2 possible ways to compare the diaries:
Two-stage pilot survey
on the same sample,
first stage using the TB diary
and second with the AB
Survey on two samples with
same characteristics per zone,
in a single stage,
each one with one diary.
To avoid "apprenticeship effect" and reluctance to participate (as respondents would have to repeat the mobility survey in a short space of time)
Sample size: 35 families per zone and procedure, representing a total of 140 families surveyed.
Sample frame: information available from the 2001 Population Census, updated via the municipal register, and telephone data currently available. Individuals above 4
Telephone contact 1
Survey fieldwork: over two weeks May 19-28, 2006.
Travel information related to one day form Monday to Thursday.
Each interviewer was to call a given set of households, always the same.
Household visit 1
Telephone contact 2
Household visit 2
The percentages of immobiles was very high. In no case did it fall below 20%, and was higher in zone C than in zone P.
This “no trips” reply is given as a soft refusal. In all likelihood, this is a consequence of the data collection method used, as this was only a pilot survey, and not properly publicised, so that a relatively high proportion of the population decided not to collaborate out of distrust. This phenomenon was more pronounced in zone C where more elderly people live alone and tend to be distrustful.
The average mobility rate obtained per AB travel diary proved in fact to be higher than the average obtained for the TB diary.
The trip rate obtained per TB diary led to believe that mobility was the same in zone C and zone P (2,29 against 2,21).
BUT when changing of diary a difference appeared between the two zones (3,59 in zone C against 2,83 in zone P). TB diary did not disregard a uniform mobility percentage for the entire environment; in the denser populated central areas highly representative percentages of the total real mobility could be being omitted.
An increase occurred in the daily mobility reporting as a result of the change in diary type used.
Trips tending not to be reported with the TB diary correspond to non-essential mobility and to trips corresponding to run-on travel movements.
BUT, the travel modes not reported in the TB diary corresponded to public transport in zone C and private vehicle in zone P the more a mode is used to travel, the more the respondent tends to forget it?
The results obtained point to the need to study a possible evolution in the household mobility surveys run in Spain towards an activity-based travel diary, in order to obtain more finely tuned mobility results.
This pilot survey was run on a local basis. In the event of wanting to extend this type of changes to a national survey, the possibility would need to be studied of replacing the household visit for data collection by a postal survey as a means of tackling the geographical dispersion of the sample in a more cost‑effective way.
did I go?
How did I get there?
What was I doing?