Singapore is set to introduce a new pay-as-you-drive system for its electronic road pricing (ERP), in which motorists will be charged based on distance covered instead of the fixed fee in place now. The navigation-based system will be introduced next year.

Motorists will have to switch from their existing ERP in-vehicle units to new on-board units (OBU), and the country’s Land Transport Authority (LTA) has said that the replacement exercise will be carried out progressively, as The Straits Times reports.

The first replacement will be done free of charge, with the installation likely to be carried out at vehicle inspection centres and appointed workshops. During the transition period, which has been reported as being around 18 months, both old and ERP systems will be operational.

Images of the supposed new OBU surfaced on online forums, but the LTA said that the photos were of photo illustrations from a 2016 study conducted on the project. The authority said that the new OBU was still being evaluated and not finalised. According to the report, the new OBU is expected to be larger than the current unit and will display information such as charges incurred for a journey.