  In this paper, we assess the impact of a fare-free public transport policy
for overnight guests on travel mode choice to a Swiss tourism destination. The
policy directly targets domestic transport to and from a destination, the
substantial contributor to the CO2 emissions of overnight trips. Based on a
survey sample, we identify the effect with the help of the random element that
the information on the offer from a hotelier to the guest varies in day-to-day
business. We estimate a shift from private cars to public transport due to the
policy of, on average, 14.8 and 11.6 percentage points, depending on the
application of propensity score matching and causal forest. This knowledge is
relevant for policy-makers to design future offers that include more
sustainable travels to a destination. Overall, our paper exemplifies how such
an effect of comparable natural experiments in the travel and tourism industry
can be properly identified with a causal framework and underlying assumptions.
