Thursday, April 19, 2018

Ex-ante evaluation of the accessibility impacts of transport policy scenarios: equity assessment of BRT expansion

About a month ago, I submitted the 4th paper of my PhD research for publication. The preprint of the paper is available at Open Science Framework (OSF), and you can download it here. Please feel free to read and cite share the manuscript. Suggestions and  criticisms  nice comments are always welcome.

Pereira, R. H. (2018). Ex-ante evaluation of the accessibility impacts of transport policy scenarios: equity and sensitivity to travel time thresholds for Bus Rapid Transit expansion in Rio de Janeiro. OSF Preprints

The accessibility impacts of transport projects ex-post implementation are generally evaluated using cumulative opportunity measures based on a single travel time threshold. Fewer studies have explored how ex-ante accessibility appraisal of transport plans can be used to evaluate policy scenarios and their impacts for different social groups or examined whether the results of project appraisals are sensitive to the time threshold of choice. This paper analyzes how different scenarios of full and partial implementation of the TransBrasil BRT project in Rio de Janeiro (Brazil) will likely impact the number of jobs accessible to the population of different income levels under various travel time thresholds of 30, 60, 90 and 120 minutes. Compared to a partial operation scenario, the full implementation of TransBrasil that extends this corridor into the city center would lead to higher accessibility gains due to network effects of connecting this BRT to other transport modes. Nonetheless, the size of the accessibility impacts of the proposed BRT as well as its distribution across income classes would significantly change depending on the time threshold chosen for the accessibility analysis. Considering cut-off times of 30 or 60 minutes, both scenarios of TransBrasil would lead to higher accessibility impacts in general and particularly for low-income groups, moving Rio towards a more equitable transportation system. However, under longer thresholds of 90 and 120 minutes, an evaluation of this project would find much smaller accessibility gains more evenly distributed by income levels. The paper highlights how time threshold choice in cumulative opportunity measures can have important but overlooked implications for policy evaluation.

Some of the core findings of the paper mentioned in the abstract are illustrated in the figure below. The figure brings box plots that show the distribution of gains in job accessibility via public transport by income groups under partial and full operation scenarios of the TransBrasil BRT project in Rio de Janeiro. The results are shown separately given different choices of travel time thresholds in the accessibility analysis.

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