# **1. Introduction**

Rapid urbanization is one of the defining characteristics of the development process experience in many low- and middle-income countries. Infrastructure development is usually unable to keep pace with urban population growth, thereby generating the inefficient provision of essential services. Transportation is a particularly relevant example. A lack of planning gives rise to inadequate infrastructure, leading to saturated roads and low rates of mobility. In such a setting, public transportation is mostly provided by private actors who rely on the same overburdened roads. Experience indicates that only if the population pressure abates are more serious efforts at improving urban infrastructure and public services undertaken. This must happen under the additional constraints imposed by the existing urban structure. Latin America is a case in point. According to World Bank data, the region’s population growth rate, including the Caribbean, peaked at 2.8 percent in 1961 and had declined to 1.0 percent by 2015.<sup>2</sup> The corresponding numbers for Colombia are a high of 3.0 percent in 1962 and a subsequent decrease to 0.9 percent in 2015. The urban population growth rate reached 4.4 percent in Latin America and the Caribbean in 1963 and stands currently at 1.4 percent, whereas Colombia exhibited a steady drop from 5.9 percent in 1960 to 1.4 percent. Today, 80 percent of Latin Americans and 77 percent of Colombians live in urban areas, up from 49 percent and 45 percent, respectively, in 1960. However, only recently have governments begun to improve urban infrastructure and services, particularly in poorer neighborhoods.

In this context, bus rapid transit (BRT) systems have shown dramatic growth over the recent decade. This urban mass transport, usually based on dedicated lanes that allow buses rapid mobility, has been implemented in 205 cities across the world and transports 34 million passengers daily over 5,600 kilometers.<sup>3</sup> Case studies point to the benefits of BRT systems, including in reduced travel time, improved air quality, curtailed greenhouse gas emissions, and the prevention of road accidents (Carrigan et al. 2013). However, research on outcomes such as employment, economic activity, or school attendance is almost nonexistent. One may attribute the gap in knowledge to a lack of appropriate data. Because households and firms may relocate in response to transportation infrastructure, one would need proper longitudinal data to assess the direct effects of infrastructure satisfactorily. Employing pooled cross-sections, as is often done in policy evaluation on other topics, runs the risk of confounding causal effects and changes in the underlying population in answer to a policy. Longitudinal data that are representative of a city or metropolitan area, however, are rarely available. In a recent review of the evidence on the impact of transportation infrastructure on economic growth, Deng (2013) discusses no evidence on urban transportation. All 18 studies discussed conduct their analyses at higher levels of aggregation (counties, states, provinces, or nations).

The present study analyzes the distributional effects of Barranquilla’s BRT system, Transmetro, first inaugurated in 2010. It shows that, even though the system was planned to target poorer households, it effectively led to a displacement of households in the city’s two lowest income quintiles by those in

> 2 See Population Growth (annual %) (database), World Bank, Washington, DC, http://data.worldbank.org/indicator/SP.POP.GROW.

> 3 See Global BRT Data (database), World Resources Institute–Ross Center, Brasil Sustainable Cities, Porto Alegre, Brazil, https://brtdata.org/.

2