Data Collection for Understanding Urban Goods Movement - Sustainable Urban Logistics: Concepts, Methods and Information Systems - page 79

Both face-to-face, postal and electronic questionnaires have been used for
carrying out the various survey techniques discussed. Interviews have been con-
ducted both face-to-face and by telephone. In the case of detailed interviews, these
are often carried out face-to-face because the topics and questions can be both
lengthy and complicated. Large-scale national freight surveys in the European
countries surveyed tend to make use of postal questionnaires. These surveys
usually have high response rates due to the fact that they are often statutory
surveys. In addition, these surveys usually have a well developed and refined
methodology and sampling approach—this is a reflection of the time over which
the survey has been taking place and the resources available to carry it out.
Interviews and group discussion techniques tend to be more widely used in one-
off or occasional data collection exercises that take place in a specific urban area.
This is due to the cost of these approaches in a national survey. Data collection
exercises in a specific urban area tend to also make use of all the other techniques
listed above. As a result of budgetary and time constraints, sample sizes for one-off
data collection exercises in specific towns and cities are often small and not
statistically representative. This makes the comparison of data over time and
between different urban areas very difficult.
New technology offers the possibility to collect significant quantities of urban
freight data at relatively low cost (compared with previous techniques). However
consideration of such techniques to collect urban freight data raises many questions
about: (i) its legality (for instance the use of roadside cameras to record vehicle
details is not currently allowed in Germany), (ii) the need to supplement this data
with other data as these new technologies do not necessarily provide all the data that
would have been collected in a traditional survey, and (iii) the co-operation and
agreement needed between the public and private sector to share this data.
Finally, it is important to highlight that survey methods are expensive and policy
makers do not always have the resources to carry out them with the detail level needed
to ensure a minimum quantity and quality of results. To deal with this limit, a small
group of tools are today available to assist policy makers. These tools are in general
depending on a regional or national context and are not present in all countries. For
more information on data production, see in this chapter and '' Comprehensive
Freight Demand Data Collection Framework for Large Urban Areas ' ' of the present
topic (Holguin-Veras and Jaller 2013 ; Gonzalez-Feliu et al. 2013 ).
6 Gaps in Urban Freight Data
The responses provided by freight transport data experts in ten European countries
carried out as part of this project have identified a range of urban freight data gaps.
These gaps have implications both for understanding urban freight transport
activity patterns and also for developing urban freight models. Issues that have
been identified by the experts in considering urban freight data gaps include: