<!-- Start of picture text --> Total 28,791 100% 14,993 100% 43,785 100%<br><!-- End of picture text --> _Source_ : Reed, T. and S. Trubetskoy (2018) _The Belt and Road Initiative and the Value of Urban Land._ World Bank mimeo.

# B.  Road & Rail Typologies

We subdivide each type of transport infrastructure following Reed and Trubetskoy (2018) to consider: undivided roads, divided roads, conventional rail, and high‐capacity rail. The four categories are described below with particular reference to proximities of both population centers and intact frontier landscapes – two factors that are especially important for understanding investments’ environmental risks.

- _High Capacity Rail:_ High‐capacity rail is dual track and/or electrified rail that transport freight and/or passengers, including high‐speed rail (HSR). HSR are defined as high capacity and frequency railway services achieving an average speed of over 200 km/hr (Givoni 2006). The HSR systems have restricted geographic access because passengers and/or freight are limited to entry/exit at very few stations. Further, those HSR stations are usually sited either in or adjacent to pre‐existing urban centers, thus limiting new access to frontier landscapes.<sup>3</sup>

- _Conventional Rail:_ Conventional rail travel is at speeds less than 200 km/hr and is typically fueled by diesel or other fossil fuels. Conventional rail stops at many more stations than the high‐speed rail, thus creating many more entry points to access frontier landscapes. Smaller stations are sited in less populated areas, potentially increasing access to intact frontier landscapes.

- _Divided Highway:_ These “high‐quality” roads, classified as four‐lane highways or larger, tend to be sited between large urban areas, though they may pass through less developed areas. They are restricted to high speed traffic. The divided highways often have limited or controlled access. The degree of access depends on the frequency of off‐ramps. Access may also be restricted through tolls.

- _Undivided Highway:_ These are “low‐quality” roads, i.e., roads which have no more than two lanes but are serviceable for transporting freight. They  connect population centers of varied sizes and are less likely to feature restrictions on access through ramps and/or tolls. BRI undivided highways may also be constructed to connect to other transport hubs (for example, to larger BRI projects) such as dryports, airports, or train stations. Because undivided highways typically have unrestricted access for entry and exit, new roads may expand gateways into undeveloped frontiers.

There are several additional categories of minor roads – roads smaller than undivided highways – that also have environmental risks but typically are not a focus of BRI projects. These can range from smaller two‐lane highways to unpaved seasonal or logging roads. Minor roads could be included within the BRI as a form of access to primary BRI projects. Additionally, unplanned spur roads that diverge from larger roads (typically from undivided highways, due to their unrestricted access) may spontaneously result from planned BRI projects. Spur roads might penetrate into frontier landscapes, yielding, for instance, a grid of "fishbone development" as has been extensively documented in the Amazon (Barber et al. 2014).

> 3 HSR is often flanked by roads for maintenance and emergencies that may provide some access between stations.

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