Cycle highways are regarded as a promising new type of infrastructure because they promote longer-distance cycling between (sub)urban residential areas and work and study centers. This study examines whether the emerging network of regional cycle highways in the Netherlands has contributed to a modal shift from car to bicycle. More specifically, we investigate the effect of these routes on commuting bicycle mode choice. Our main data sources are a national travel survey covering commuting journeys that were made between 2010 and 2021 and a comprehensive dataset we have compiled to document the exact timing and status of all cycle highways in the Netherlands. We employ a difference-in-differences approach with a binary logit model, comparing bicycle mode choice versus the car for trips that benefited from a new cycle highway, before and after the introduction of the new infrastructure, with a control group of trips that were not affected by the construction of a new route. We present results from a novel routing-based approach to measuring exposure to this new cycling facility, which allows us to establish the extent to which the fastest route to work traverses a newly constructed cycle highway. After controlling for relevant covariates, our main results indicate that the introduction of cycle highways has contributed to a shift in commuting behavior toward cycling, with an increase of approximately 10 % in cycling probability post-intervention for trips highly exposed to cycle highways. The results also indicate some heterogeneity in the effects of cycle highways across different groups of individuals. The findings of this study are especially important in the context of the Netherlands (or similar biking countries, such as Denmark). Although these countries have well-established cycling infrastructure, they can still derive benefits from new cycling routes and can support decision-makers in other countries who want to invest in cycling in the near future.