assessing the impact of BRT systems on employment, the distribution of ridership, accessibility, and health.<sup>4</sup> Few studies look at labor market outcomes. Two exceptions are Heres, Jack, and Salon (2014) and Olarte Bacares (2013), which both look at Colombia’s first BRT system, the TransMilenio system in the capital, Bogotá. Olarte Bacares estimates ordinary least squares and two-stage least squares models of the effect of TransMilenio according to the exposure of Bogotá’s 112 planning zones to the system. He finds that jobs became more accessible and that employment increased in areas with higher exposure. However, income was unaffected in most specifications. While the study considers exposure a potentially endogenous variable, it does not take into account the degree to which the outcomes may be driven by changes in the composition of resident households and firms.

Heres, Jack, and Salon (2014) employ data similar to the data of the present study. They find that income rose among households in proximity, but not immediately adjacent to TransMilenio stations. However, because the data used are pooled cross-sections, the authors admit that their results are likely driven by changes in household composition.

In terms of job creation, Hidalgo et al. (2013) find a positive balance after the implementation of TransMilenio whereby the creation of new jobs overcompensated for the jobs lost through the phasing out of traditional buses. Venter, Hidalgo, and Valderrama Pineda (2013) assert that new jobs are more likely to be created if there are specific policies, such as in Johannesburg, providing that minibus drivers were retrained and employed as bus drivers or station staff.

Many recent studies on Bogotá’s TransMilenio seek to evaluate whether the system had net positive effects on the welfare of users or the broader public. Relying on different specific assumptions, these exercises estimate or calibrate a user demand function to derive monetary values for time savings and greater convenience. Other factors, such as operator benefits, reduced air pollution, improved traffic conditions, or security are also included on the benefit side. These are then compared with total costs under various discount rates on the initial capital investment. In this respect, Chaparro (2002), focusing on the first phase of implementation, finds large positive welfare effects. However, these results are contradicted by Echeverry et al. (2005), who also focus on the first implementation phase and find positive effects among the direct beneficiaries of the system, but negative effects among users in areas away from the system within the same city. Hidalgo et al. (2013) also find that TransMilenio exerts a net positive effect, but point out that this is much smaller than the outcome envisaged in the ex ante evaluation, mostly because of cost overruns and delays during initial construction.

In a survey of BRT systems across the world, Hidalgo and Gutiérrez (2013) highlight the substantial associated positive externalities. Yet, as they point out, planning, implementation, and operation are not without issues, and, in many instances, the systems are viewed as second best relative to light rail. Other research has highlighted the negative externalities, such as the potential for the geographical

> 4 Venter, Hidalgo, and Valderrama Pineda (2013) and Venter et al. (2017) provide an excellent review.

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