Evaluating urban planning: evidence from Dar es Salaam
Urban informality, which is prevalent in Africa's rapidly growing cities, can reduce private investments, lower tax bases, and exacerbate urban disamenities. A key policy tool to address this problem is greenfield urban planning where governments purchase cheap agricultural land on the urban fringe and partition it into planned, surveyed, and titled de novo plots, which people can purchase and build houses on. Yet, there is very little systematic evidence on the effects of de novo planning choices, such as the size and configuration of residential and non-residential plots. We model and study the consequences of such planning decisions in Tanzania's "20,000 plot" project, which provided over 36,000 residential plots in 12 project areas on the fringes of Dar es Salaam in the early 2000s. We study this project using detailed maps, questionnaires, and satellite imagery, and we combine within-neighborhood analysis and spatial regression discontinuity designs. We find that overall, the project secured property rights and access, thus boosting land values, and attracting highly educated owners; small plots, which command higher land values and are built more intensively, are under-provided; access to main paved roads is prized; and development rates are higher where plot layout is more gridded and small plots are bunched together. But planned non-residential amenities are ignored due to low implementation rates and about half the plots are still unbuilt, suggesting that despite the project's success, significant improvements are possible.