networks and speed assumptions from de Soyres et al. (2019). In doing so, we limit the analysis to road and maritime routes for shipments within Africa, while considering rail and maritime connections for shipments to the rest of the world.<sup>4</sup> Two main reasons justify this approach. First, road is by far the main transport mode for trade within Africa, while most international trade in the rest of the world travels by sea and by rail.<sup>5</sup> Maritime shipping accounts for 80% in volume and 70% in value of global trade and rail is the second transportation mode used (International Transport Forum 2017). Second, most transport reforms in Africa included in the PIDA, as discussed in detail in section 3, consist of road and maritime infrastructure investments. This approach allows us to incorporate most of PIDA’s proposed interventions.

We then integrate the land transport network by including delays at (land and sea) borders and cargo loading and unloading times at seaports. For this purpose, we first use the World Bank’s Doing Business indicators, which provide country-level information on the ease of crossing land or sea borders by measuring the number of documents required to trade, days to cross the border, and costs associated with exporting and importing.<sup>6</sup> We limit our analysis to waiting times to import and export for the latest year available in the dataset. If a country has a maritime gateway, we consider both delays at the land border and delays at the maritime border.

For each country, we define both land and sea border delays if the country is coastal and only land border delays if the country is landlocked. Because data are reported only for the most used gateway per country, which for coastal countries is generally a port, we assume that unobserved land-border times are a fraction of reported sea-border times.<sup>7</sup> In addition to delays at the maritime border, ships may experience additional delays for loading and unloading, which we calibrate using the median number of days container ships stay in ports, derived from UNCTAD data.<sup>8</sup> Finally, to combine data on land borders and port delays, we rely on the following assumptions. (i) Trucks crossing a border must pass through customs in the country of departure and the country of arrival (total crossing times are equal to the sum of times at the border of departure and the border of arrival). (ii) Export and import procedures at sea borders add up to logistics delays at ports (total times at sea borders are the sum of the country’s sea clearance time plus delays at ports).

In order to reduce border delays, several countries have implemented One-Stop-Border Posts (OSBP) to enable goods, people, and vehicles to stop in a single facility in which they undergo necessary controls to exit one state and enter the adjoining state. We include such facilities using maps and status information from the PIDA dashboard which includes up-to-date implementation status and various sources (World Bank reports

> 4Air transport is likely to be the preferred option for perishable goods, especially flowers (HS06) or vegetables (HS07). These goods represent less than 0.04 percent of an African country’s total exports in 2018. If all chapters from HS01 to HS08 are considered as perishable goods, the share is still less than 0.09 per cent.

> 5The prevalence of roads as a mode of transportation is also reflected in the PIDA action plan, where most of the priority transportation projects concern the road network (or a combination of roads and borders). Railways, on the other hand, are typically associated with port hub development, except for the Djibouti-Addis corridor and the Kinshasa-Brazzaville road-rail bridge project. We also prioritize road transport because the rail network in Africa is composed of several disconnected components with heterogeneous market sizes, making them difficult to compare.

> 6Note that we use border compliance time and do not include export documentation compliance (which is a one-time cost). Whether the country of entry is the final destination of the shipment or just a transit point, the border compliance time is the same. There may be a risk of overestimating border compliance time for transit shipments. However, in a non-free trade zone, it is not obvious that transit trucks would have less wait time than trucks arriving at their final destination. In the context of a broad study of Africa, using a single border wait time seems a safe simplifying assumption.

> 7Details can be found in Table A2 in the Appendix A.

> 8UNCATD reports ship dwell time at ports, this information is constructed from Maritime Traffic data and can be accessed here: `https://unctadstat.unctad.org/wds/TableViewer/tableView.aspx`

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