The Electronic Road Pricing (ERP) system has served Singapore well in keeping roads relative free from congestion.

As a result, the ERP charging during the evenings and Saturdays will not be removed at the moment, said Transport Minister Lui Tuck Yew in Parliament on Wednesday.

"Since the ERP rate reductions we have made in October 2011 and June 2012, we have generally observed heavier traffic flow and thus lower traffic speeds in the time slots where we had cut ERP rates," he said.

Mr Lui also announced that the Land Transport Authority is studying the feasibility of a "reversible flow" traffic scheme which he noted would be ideal for stretches where traffic data shows a "tidal pattern".

This, he explained, means the traffic is heavy in mainly one direction during the morning peak hours and in the opposite direction in the evening.

Stretches along the Kranji Expressway and the Pan Island-Expressway have been identified as possible corridors for this scheme, he said.