To inform policies aimed at more sustainable travel behaviour, previous research has investigated the concept of multimodality. The notion underlying this line of research is that increasing the degree of multimodality will lead to less car dependence and therefore more sustainable travel behaviour. This paper investigates multimodality by inferring modality styles and revealing their response to exogenous variation in the form of the weather. The main idea of this paper is that travellers with a more multimodal modality style are more sensitive to exogenous variation, and that they are therefore more likely to resort to the use of the car when ‘car-favouring’ conditions present themselves. The results show that the effects of weather conditions on mode choices do indeed differ between three modality styles. The identified modality styles can be summarised as (1) bike + car; (2) car mostly and (3) multimodal. For the third class, which has the highest degree of multimodality, the use of the sustainable modes is more strongly affected by weather conditions when compared to the first, less multimodal, class. The least multimodal second class meanwhile is least affected by a change in weather conditions. More multimodal travellers thus seem to be more susceptible to exogenous variation, which might prevent the formation of sustainable travel habits or patterns. Based on these results, the claim that a higher degree of multimodality will lead to more sustainable behaviour and that policy makers should aim to realise a shift towards more multimodal modality styles needs to be nuanced. Policy makers should instead focus directly on increasing the attractiveness of sustainable travel modes, which will inadvertently lead to more multimodal modality styles.

Residential self-selection (RSS) is the theoretical mechanism that explains that the impact of the built environment on travel behaviour is weaker than bivariate correlations suggest, because mode attitudes influence both the built environment and travel behaviour and therefore at least partially account for the bivariate relationship. Recently, the concept of travel-related reasons for residential choice has been introduced, which reflects the actual extent to which the travel-related characteristics of the built environment were considered during the relocation decision. In this paper, we hypothesize that travel-related location reasons are stronger predictors of the built environment choice than generic mode attitudes. This hypothesis is examined by estimating both a cross-sectional and a longitudinal Structural Equation Model using data gathered in the Netherlands. The results suggest that the travel-related location reasons are indeed stronger predictors for built environment location than travel mode attitudes and that the directions of causality between attitudes, travel-related location reasons, the built environment, and travel behaviour often run in both directions. Substantively, our findings indicate that public transport use is most strongly affected by the built environment (after controlling for both stated reasons and attitudes), while car and bicycle use are hardly affected. From a practical point of view, this suggests that transforming the built environment to be more friendly to public transport may increase the use of public transport, but that, at least in the Netherlands, such a strategy would not work well if the aim were to reduce car use or increase bicycle use.