QAMECS-SHS, Représentations, perceptions et pratiques de mobilité: quelles implications pour les politiques publiques?

Widespread car use has serious health consequences through degradation of air quality and lack of physical activity. Yet individual behaviour is known to be difficult to change. This is why QAMECS-SHS aims, in an approach combining sociology, psychology and economics, to understand the individual, psychological and communicational levers on which to rely in order to encourage changes in behaviour and thus define policies that are effective in terms of health and socially acceptable. We are using the Grenoble urban area as our field of study and relying on original data collection. We are conducting the first evaluation of the determinants of the social acceptability of a low-emission zone (LEZ) prior to its adoption. The results show that the LEZ project is accepted by a majority of respondents and that positive perceptions of the impacts of the LEZ are the main determinants of this acceptability. People who have a vehicle that will be banned in the LEZ express less acceptability as well as people with little habits of active mobility. Socio-demographic characteristics do not determine the level of individual acceptability. In the event of the implementation of the LEZ, modal shifts would be favoured as an adaptation solution, particularly in the context of home-work trips, but the physical, economic and social accessibility of public transport are strongly called upon to accompany the implementation of the LEZ. These results encourage us to study the determinants of active mobility behaviour intentions. We show that self-determined motivation (i.e. feeling of pleasure, belief in the usefulness and importance of modal shift) is positively correlated with higher active mobility habits and modal shift intentions. The effect of this type of motivation on intentions by considering habits is only indirect, confirming the strong influence of mobility habits on behaviour change. On the contrary, non- self-determined motivation (i.e. social pressure, fear of being criticised or judged) is negatively correlated with active mobility habits and does not significantly influence modal shift intentions. Finally, we show that the communication of information on health risks related to both air pollution and lack of physical activity are able to influence participants' modal choice intentions. The willingness to pay (WTP) to reduce individual risk is equal to €0.85 per public transport trip for a risk reduction of 2 percentage points, while the WTP to reduce population risk varies between €0.80 and €1.29 depending on the share of the population also adopting alternative modes to the car. Similar values are found for cycling. Given the current modal shares, policy makers could therefore play on the impact of modal choices on both individual and population health to encourage citizens to reduce car use.