Household travel surveys response rates are decreasing. Efforts are made to increase response rate for traditional survey by improving the questionnaire, reducing respondent burden, increasing reminders… Even if results are generally positive, it is in most cases not sufficient. Weighting aims at reducing the impact of non response, but it is always necessary to postulate that people with some socio-demographic characteristics who do not respond to a survey have the same behaviour than people with the same socio-demographic characteristics who respond. But evidence seems to indicate that it is not always the case for travel. To reduce this bias of non-response, we have realised a web survey in parallel of the 2006 household travel survey conducted in face to face in Lyon. The idea was to propose to households who refuse to respond in face to face or was not reachable after a certain number of attempts to respond by the web.
This new and interactive mode of data collection offers to the respondents the possibility to choose a nice moment to complete the questionnaire. However, Internet penetration rate is still low, and users’ capabilities and equipment vary a lot. Therefore the generalization of the results to the whole population remains inaccurate. Moreover, the implementation of a Web survey raises specific problems, in terms of design and administration of the questionnaire. Lastly, the danger when databases are merged is that a sample selection bias will be created.
The paper initially discusses web potential for households travel surveys, especially in a mixed modes framework. Then, some thoughts on Lyon on-line questionnaire and the choices operated compared to its paper version are provided. We present the results of the Lyon web travel survey compared to the face-to-face survey, and characterize a selection bias. Finally, we give some perspectives for future households travel surveys.