CBS mapping goods flows

Employee pulling a hand pallet truck
© Hollandse Hoogte / Guus Schoonewille fotografie
How much coal, oar, machinery, electronics and waste enter and leave the Netherlands? Is this by sea container, by rail, on an inland vessel or by lorry? What about the destination or origin of the cargo: Germany or Belgium, or rather the United States or China? Are the goods consumed here, or do they leave the country again in transit to other countries? Using new methodology, CBS is able to combine data on international trade and transport in order to provide the answers to these and other questions. This research has been commissioned by Rijkswaterstaat, the KiM Netherlands Institute for Transport Policy Analysis and the Directorate-General for Aviation and Maritime Affairs.

Integrated trade and transport figures

In the past, CBS used to produce separate datasets with either international trade data or transport data. The international trade dataset contains the value of goods entering and leaving the country as well as countries of origin and of destination. Transport datasets list the weight of the goods, the modes of transport, and loading and unloading locations. ‘We’ve now bundled all these data,’ explains Chris de Blois, who leads the trade and transport data integration project at CBS. ‘This means we can produce a comprehensive overview of all the goods flows towards and out of the country. We used to have data on the value of Dutch goods imports and exports, for example cocoa bean imports from Brazil and pork exports to Spain. But there were no data on the exact gross weight in kg and the mode of cross-border transportation. Aside from this, we had information on how and where goods were shipped across the border and their volume, e.g. how many tonnes of cocoa beans arrived in the Port of Amsterdam by cargo vessel. But we did not know anything about the value of such goods and their origin. By bundling the data we are now able to describe imports, exports and transit trade in terms of both value (euros) and volume (kg); we know by which mode of transport they are carried, where they come from originally, and where they are taken.’


This comprehensive overview of supply chains was developed at the request of Rijkswaterstaat and others. They deploy combined trade-transport data in order to develop strategic goods transport models. Remko Smit, advisor for traffic and transport models at Rijkswaterstaat and commissioning party for the import and export statistics, explains: ‘The separate trade and transport data would sometimes show small discrepancies and this raised questions. Now both sets of data have been integrated properly, which has given a further boost to the consistency and quality. This means we are better able to monitor the historic development of goods flows and produce even more accurate forecasts of future developments now.’ This insight is vital in policymaking, according to John Spruijt, advisor for traffic and transport models at Rijkswaterstaat and project leader in chain data: ‘Based on these models, we can take decisions regarding investments in our infrastructure. Once you know where we anticipate an increases or decrease in goods transport, you also know where the infrastructure will be used more or instead less heavily. In other words, whether to invest in ports, roads, inland navigation or railways.’

Local developments

Rijkswaterstaat links integrated trade and transport data to other data as well, e.g. road transport data of CBS. This enables them to produce estimates of local developments using their own models. Spruijt explains: ‘For example, we map the locations of terminals -transhipment points from inland navigation to road or railway transport. This is how we can identify the locations where such infrastructures are deployed. We also want to find out where there is space left at terminals and where there are possibilities of switching between transport modes.’ Knowledge about local conditions is also useful during calamities. ‘Using our models we have a clear picture of how the infrastructure is being used for the various goods flows,’ Smit says. ‘For example, if inland navigation is affected by periods of prolonged drought, these models can help find alternatives, so that goods transport can still take place.’

Specific goods

As some goods can only be carried in one particular way, it is important to Rijkswaterstaat to have the various types of goods flows in overview. Says Smit: ‘Coal, for instance, is shipped by inland vessels and by rail. This is a substantial flow of goods. As coal-fired power plants are disappearing, it is important to know how coal transport is divided over the different modes of transport. As such, the CBS integration model of trade and transport data distinguishes between around 20 different types of goods, such as electronics, textiles and leather, waste, natural gas and oil. ‘The CBS classification matches that of Rijkswaterstaat,’ says De Blois. ‘Basically, we can also select very specific products – for example potatoes – and produce a string of calculations for that.’

Transit to third countries

Another advantage of the new integration method is that it makes measurable how many incoming goods stay in the country, how many goods are forwarded in transit and by what mode of transport. De Blois: ‘We now have a proper idea of the so-called transit volumes. Transit goods are foreign-owned goods entering the country and then forwarded to other countries. For example, coal from Colombia arrives in the Port of Rotterdam and is then shipped to Germany via inland waterways.’ This also clarifies how Dutch infrastructure works are used in the transportation of foreign-owned goods. The costs and benefits can be calculated accordingly. How much is earned in transit trade? How much does it cost? And what is the contribution to CO2 emissions, for instance?

Complex methodology

The development of the integration model for trade and transport data was complex. The methodology department at CBS played an important role in the process. ‘They developed an estimation model that also offers error margins and thus indicates the reliability, also for the various combinations of transport modes and types of goods,’ De Blois explains. This extensive methodological know-how at CBS is of great added value in the partnership with Rijkswaterstaat. Says Smit: ‘CBS is independent and reliable and focuses a great deal on research quality. They have access to source data and the expertise needed to convert these into statistics. Our collaboration with CBS is also pleasant and constructive; they think along with us as to how their statistics may serve our information needs.’