Hélène Bouscasse

Sandrine Mathy

Rim Rejeb

Carole Treibich

Is the impact of transport modes on health an individual determinant of transport mode choice?

 Modal choice generates individual and public health issues.  Modal shift to active and less polluting modes is a valid strategy to reduce: • Individual health risk related to (a lack of) physical activity (Tainio et al., 2016).

• Public health risk related to air pollution (Bouscasse et al., 2022).

• Assess the way introducing these two health dimensions in the individual choice process could influence modal shift intentions

• Account for the perception of health risks in the study of mobility behavior

• Our findings confirm that information on health risks related to air pollution or lack of physical activity both have a significant effect on the preferences of the participants in regards to modal choice. • Today, in Grenoble, the modal share of people using an alternative mode to the car is rather around 50% or lower, our results indicate that decision makers could play on both the individual and public health impact of modal choices to incent citizens to reduce car usage.

• Original data: Online Discrete Choice Experiment (June to September 2019) . 792 residents of Grenoble Métropolitan Area (France).

• 3 modes of transport: car, public transport and bicycle.

• 4 Attributes: Travel time, Cost, Individual (through physical activity) and Public (Through air pollution) health risk with framing (50%, 75%, 90% shares of the population).

• Illustrating the health risk of developping a cardiovascular disease  Use of smileys (Green = health gain risk).

• Discrete Choice Modelling accounting for the perception of risk reduction probabilities using a power transformation (Bouscasse and de Lapparent, 2020, Yaari, 1987) .

• more significant effect of the individual risk reduction in encouraging the use of alternatives to the private car compared to the public risk reduction when there is a relatively small share of the population (50%) already using alternatives. • However, when larger shares of the population already adopt the behaviour (75% or 90%), the information about the public risk reduction has a larger impact on the mobility preferences than the individual risk reduction.

• For both types of information, the risk reduction seems to be generally under-estimated by the participants.

• Altogether, we find significant and positive mean willingness to pay for these risk reductions when using alterntives to the private car. • Individual risk reduction: More significant effect in encouraging modal shift compared to public risk when there is a relatively small share of the population (50%) already using alternatives. • Public risk reduction: Has a larger impact on the mobility preferences than the individual risk reduction with larger shares of the population (75% or 90%) . • Both types of information: the risk reduction is generally under-estimated by the participants.

  ., & de Lapparent, M. (2020). A rank-dependent utility approach to model intra-and inter-individual heterogeneity in risky choice behaviours. Applied Economics, 52(31), 3337-3353. Bouscasse, H., Gabet, S., Kerneis, G., Provent, A., Rieux, C., Salem, N. B., ... & Slama, R. (2022). Designing local air pollution policies focusing on mobility and heating to avoid a targeted number of pollution-related deaths: Forward and backward approaches combining air pollution modeling, health impact assessment and cost-benefit analysis. Environment international, 159, 107030. Tainio, M., de Nazelle, A. J., Götschi, T., Kahlmeier, S., Rojas-Rueda, D., Nieuwenhuijsen, M. J., de Sá, T. H., Kelly, P., and Woodcock, J. (2016). Can air pollution negate the health benefits of cycling and walking? Preventive medicine, 87:233-236. Yaari, M. E.(1987). The dual theory of choice under risk. Econometrica: Journal of the Econometric Society, pages 95-115.

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 : Figure: Willingness to pay to reduce risk of developing a cardiovascular disease