a good case study on the effect of BRT systems or, more generally, access to improved public transport in midsize cities. The second reason is that data are readily available on the transportation system of Barranquilla since it entered into service in 2010. This allows one to take advantage of the yearly progress in the implementation of the system to identify impacts. The third reason is that the topology of Barranquilla is entirely flat, unlike most other Colombian cities. This is important because it allows distances to bus stations along the city’s street grid to be measured easily in comparative terms, which would be challenging in a city set into foothills or mountainous terrain.

The Council of National Economic and Social Policy described the equipment and infrastructure of the public transportation system in Colombia as obsolete and characterized the service as inadequate and generally poor (CONPES 2003). After the launch of Bogotá’s TransMilenio, the government decided to promote mass rapid transit systems in cities with high population densities. One such location, the Barranquilla metropolitan area, is, according to the council, characterized by (a) the forced displacement of rural families toward urban areas, (b) an increase in the population share of the lowest socioeconomic strata, and (c) substantial dependency on the city of Barranquilla as the regional center of economic activity (CONPES 2004). In consequence, the Transmetro system was expected to benefit particularly the poorest households in the urban periphery through better connectivity and lower fares.

Map A.1 provides a visual overview of the Transmetro BRT system (see the appendix). The system serves the municipalities of Barranquilla and Soledad. The main lines consist of local and express stations. The local stations may be bypassed by express buses. Buses along the feeder lines either stop for connections with buses on the main lines, requiring passengers to change buses, or continue along the main routes once they reach the main lines. There are 18 stations on the main lines and over 600 stops along the feeders. The fare for a single trip was raised from Col$1,800 to Col$2,000 (around US$0.67) in 2016. The total number of passengers rose from 3,658,421 in 2010 to over 36,400,000 in 2016.<sup>5</sup> The system entered service on April 7, 2010, and, for the first three months, until July 9, it operated free of charge.

# **4. Data and Empirical Strategy**

The ideal survey structure for the assessment of the effects of a transportation system on households or individuals would consist of longitudinal data to allow respondents to be followed if they move between survey rounds. The results in any study using data that fall short of this requirement may be suspect because of the possibility of picking up effects of urban displacement, rather than causal effects, on the outcomes of interest.

The aim of the present paper is to show how the implementation of Transmetro may have changed the composition of neighborhoods in proximity to new stations. To this end, the study relies on data from the 2008–15 rounds of the Gran Encuesta Integrada de Hogares—GEIH survey, the main labor

> 5 For these and other data on the system, see “Te une a Barranquilla,” Transmetro S.A., Barranquilla, Colombia, http://www.transmetro.gov.co/.

9