The company behind the public transport smart card OV-chipkaart is beginning experiments with billing people for the journeys they have made on a monthly basis.

Trans Link Systems hopes the concept will make it easier for people who forget to load up their cards to travel by public transport. At the moment, passengers must have at least €4 on their card to use a tram and €20 to use a train.

But this can be avoided if the public transport firms can automatically charge passengers for their journeys once a month, TLS says. In addition, it will be easier for passengers to claim a refund if they have forgotten to check out because they can check their bill.

The trials will run in Rotterdam, where the OV-chipkaart was first introduced.