The success of the 9 euro rail pass introduced in Germany in increasing rail use and reducing pollution and congestion on highways is described here in The Guardian. For 9 euros one could travel throughout Germany on Deutsche Bahn rail network for one month in June, July or August. Less traffic congestion and better driving times in 23 of 26 cities in Germany, and a jump in short journeys by rail between 30 kms and 100 kms, and between 100 and 300 kms, are shown here for Germany.