Earlier this summer, for €9 a month (or about $8.99 at current exchange rates) as part of an effort to reduce dependency on private cars and encourage folks to use public transit. Now, initial data shows that the experiment worked — though the research also highlights the strain that increased ridership caused on the country’s public transportation network.

The unlimited fare scheme was implemented in response to Russia’s invasion of Ukraine. According to , the war in Ukraine raised fears of an energy crisis in Europe, and German regulators hoped to reduce the country’s energy use to ward off a potential cost-of-living crisis.

The site reported that 38 million tickets were sold, which amounts to about half of Germany’s population. Many towns and cities saw ridership reach levels not seen since before the COVID-19 pandemic, and researchers say many passengers used the unlimited pass for leisure travel, since it made those trips more affordable, . It was, by all accounts, a successful experiment.

But there were some drawbacks. Only about three percent of people opted to use public transit over private vehicles in their everyday travels, meaning traffic congestion was only reduced by a similar amount, Vox says.

Other struggles had to do with the speed with which the ticket incentive was implemented; the train system struggled to cope with the influx of riders, resulting in a lot of congestion during the first weeks of the experiment. The current infrastructure also needs plenty of maintenance, which makes it difficult for trains to operate in certain areas.

The big issue, though, is that the experiment ends on Thursday, September 1. German transit companies still face concerns over price hikes due to rising energy costs. Additional proposals, like a €365 unlimited yearly train ticket, still don’t quite reach the level of affordability offered by the €9-a-monthticket.

Reducing dependency on foreign energy, cutting down on traffic congestion, and allowing people to afford to take leisure trips — all in all, it sounds like Germany’s train experiment paid off.