Contargo, a European barge and intermodal operator, has announced it will use Port Stay Index (PSI) to set congestion surcharges in Rotterdam henceforth.

The move follows last month's introduction of the levy due to worsening congestion and longer waiting times at the Dutch seaport, reported Lloyd's Loading List.

The intermodal operator explained that "a transparent, neutral key parameter" has been developed by trade body Centraal Bureau voor de Rijn en Binnenvaart (CBRB) that measured the average handling time of containers at the port based on data supplied by member firms.

"This PSI has been measured by the CBRB since mid-April and is published weekly. Once a month, Contargo calculates a monthly average from these statistics, which is then used as the basis for calculating the congestion surcharge.

"From June 1 2015, the congestion surcharge will be determined according to this key value, with a two-month time delay, meaning that the throughput times for April will be taken as a basis for the congestion surcharge in June, the May figures will be used to determine the surcharge in July, etc. This will work exactly like the familiar bunker surcharge system (BAF), which has been in use for years."