Swedish Institute for Transport and Communications Analysis

1

• Swedish Institute for Transport and
  Communications Analysis
• www.sika-institute.se

COST355, WG3, INRETS 20 may 2005
2
About SIKA

• Established in 1995
• An government agency responsible to the Ministry
  of Industry, Employment and Communications.
• Works within the transport and communications
  sector.

COST355, WG3, INRETS 20 may 2005
3
Three main areas of responsibility

• To carry out studies for the Government
• To develop forecasts and planning methods
• To be the responsible authority for official
  statistics in the sector

COST355, WG3, INRETS 20 may 2005
4
What does SIKA do?

• Develops a co-ordinated basis for all transport
  sectors planning of infrastructure
• Makes forecasts for the transport sector
• Makes socio-economic analyses of policy, pricing
  and investment
• Develops methods for forecasts and economic
  analysis
• Co-ordinates national travel and commodity flow
  studies
• Official statistics on transport and
  communications

COST355, WG3, INRETS 20 may 2005
5
Swedish NTS History

• Survey duration 1 year
• Sample size 8 232, Response rate 89
• Personal interviews

1978

• Survey duration 1 year
• Sample size 7 518, Response rate 85
• Personal interviews

1984/85

• Continuous survey
• - Riks-RVU (1994-1998)
• - RES (1999-2001)
• Sample size and Response rate
• - RiksRVU 52 211, 77
• - RES 23 937, 72
• CATI

1994-2001
6
NTS (RES 1999-2001)

• Input to forecasting models, base for various
  analyses of mobility and for monitoring trends
• Individuals aged 6-84 years
• Register of total population
• Fixed day for data collection on daily mobility
• Data on long distance travel (gt100 km) collected
  for a longer recall period (1 month/2 months)
• Calling period 7 days
• CATI introductory letter together with a diary

COST355, WG3, INRETS 20 may 2005
7
NTS data collected

• Background questions
• Age, sex, education etc. (known variables from
  register)
• Occupation, income, driving licence
• People in the household, cars
• For a fixed day
• All trips (start, destination, purpose, all modes
  used (incl. length in km) time of starting and
  ending etc.)
• In case of a workday, where and when the
  respondent worked
• Additional questions
• Long distance travelling
• Telework/Flexible work

COST355, WG3, INRETS 20 may 2005
8
Continuous NTS possible limitations

• Don't meet the objectives
• Data quality
• Ability to follow the development of other modes
  of communications

COST355, WG3, INRETS 20 may 2005
9
1. Dont meet the objectives

• Objective analyses of trends
• Expensive survey small sample size on an annual
  basis
• Travel behaviour changes slowly
• Sample size to small to detect trends
• Objective Input to forecasting models
• Require matching data on transport supply
• Not possible to collect and encode for a long
  survey period inconsistency problems if
  collected for a given day or year
• Matching data not available

COST355, WG3, INRETS 20 may 2005
10
2. Data quality

• Sensitive for competence loss in key positions
• Interviewers performance may drop
• Once contracted, less motivated survey
  organisations

• Less administration
• Improvements of questionnaire over time
• Higher quality in geocoding (dependent of method
  used)

COST355, WG3, INRETS 20 may 2005
11
3. Other modes of communications

• Fast development of access to and use of ICT
• Effect on organisation of work
• Effect on organisation of leisure time and
  activities
• Effect on travel behaviour

COST355, WG3, INRETS 20 may 2005
12
National Communication Survey - NCS

• Covers the same areas as the NTS additional
  questions about
• Access to ICT
• Use of ICT during the fixed day
• Use of tele- and videoconferences
• Pilot studies every year 1996-2002
• Yearly sample size 1 000-2 500
• Response rates 63-75

COST355, WG3, INRETS 20 may 2005
13
Some methodological tests in the NCS
COST355, WG3, INRETS 20 may 2005
14
New system Alternating NTSs and NCSs
COST355, WG3, INRETS 20 may 2005