The high commuter demand during peak hours is a key challenge for public transport. Supersaver tickets enjoy increasing popularity among customers. Using causal machine learning approaches, we estimate the effect of the supersaver tickets on demand shift from peak to underutilized off-peak hours. There exist huge demand differences between peak and off-peak hours of public transport. The underutilized capacity of the off-peak hours is therefore a great potential to unburden peak hours using supersaver tickets.