Bus rapid transit (BRT) in developing Asia & Africa: a systematic review of the enviornmental impact and co-benefits of BRTs

We conduct a systematic review of Bus Rapid Transit (BRT) systems and their environmental and social impacts on cities across LMICs in Asia & Africa. Our search strategy involves 3 key steps. First, we search a database of BRT systems across the world to identify BRT systems in Asia & Africa and collect information about the operational characteristics of these systems. Next, we design and implement a string-based search query to find literature related to the systems identified in Step 1. And lastly, we design and implement search queries for BRT systems in general for these countries. Using these studies, we are interested in gathering estimates related to the environmental impact (mainly GHG emissions) and three major categories of co-benefits: (i) transport-related impacts, (ii) economic & social impacts, and (iii) health impacts.
Based on initial literature screening we can identify more than 120 original studies on approx. 30 BRT systems. We report three types of outcomes resulting from the search process; (i) evidence maps and gaps of BRT systems literature, (ii) evidence on transport, social, economic, and environmental impact of BRTs, and lastly (iii) critical analysis of the underlying studies, including information availability analysis, risk of bias, strength of evidence analysis. Early results suggest that while BRT systems have a more limited impact on some transport-related outcomes such as transport mode shift, their impact on accessibility and health outcomes (particularly air pollution and accidents) alone is quite large. We compare these impacts of BRT systems to other transport system interventions using standard terms of cost-benefit analysis, underlying the benefits and shortcomings of these systems. Given the nature of this systematic review, we also devise a plan to convert this review into a living review form.