VoxDev Development Economics

In cities across low- and middle-income countries, traffic crawls 24 hours a day. In Dhaka during rush hour, speeds average around 15km/h. At three in the morning, when the roads are empty, they average about 20km/h. Urban transport in the developing world is not only slow because of congestion. And so congestion policy, Adam Storeygard of Tufts University argues, gets you a small fraction of the way to solving the problems of urban transport in LMICs.
That counterintuitive finding is one many themes in Storeygard's wide-ranging review of what research actually tells us about how people in LMICs get from A to B. From informal minibuses to bus rapid transit, from a field experiment in Bangalore that tested congestion pricing to the long shadow of colonial railroads still shaping African trade today, the picture that emerges is more nuanced and more interesting than many policy blueprints suggest. He tells Tim Phillips what the evidence supports, where it runs out, and why fixing the roads won’t fix everything.
The research behind this episode:
Storeygard, Adam. 2025. "Transport in Low- and Middle-Income Countries." NBER Working Paper 34354. Forthcoming in a special issue of Regional Science and Urban Economics.
To cite this episode:
Phillips, Tim. 2026. "Transport in Low- and Middle-Income Countries." VoxDev Talk (podcast). 

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About Adam Storeygard

Adam Storeygard is Professor of Economics at Tufts University, where his research focuses on urbanisation, transportation, and the economic geography of the developing world, in particular sub-Saharan Africa. Much of his work uses geographic and satellite data to study how infrastructure shapes where people live, how they move, and how economies develop.
Research cited in this episode

Akbar, Prottoy Aman, Victor Couture, Gilles Duranton, and Adam Storeygard. 2023. "The Fast, the Slow, and the Congested: Urban Transportation in Rich and Poor Countries." NBER Working Paper 31642. The paper behind the Dhaka finding: assembling travel speed data across 1,200 cities in 152 countries, the authors show that cities in poor countries are roughly half as fast as those in rich countries, and that most of the gap is not congestion but structural low speeds in the absence of traffic.
Björkegren, Daniel, Alice Duhaut, Geetika Nagpal, and Nick Tsivanidis. 2025. "Public and Private Transit: Evidence from Lagos." Working paper. When Lagos introduced a major new public bus system, informal drivers on affected routes left,  so bus frequency on those routes fell on net. The big benefit accrued to other routes that informal drivers switched to, where prices and waiting times fell. Winners and losers, not a clean gain.
Franklin, Simon. 2018. "Location, Search Costs and Youth Unemployment: Experimental Evidence from Transport Subsidies." Economic Journal 128 (614). A randomised trial in Addis Ababa: providing transport subsidies to unemployed young people helped them search for and find formal jobs. Effects did not persist once subsidies ended, raising questions about how much the transport constraint itself was the binding one.
Borker, Girija. 2021. "Safety First: Perceived Risk of Street Harassment and Educational Choices of Women." World Bank Policy Research Working Paper 9731. Women in Delhi attend less selective colleges than male peers with identical academic credentials, not because they are not admitted, but because of perceived harassment risk during the commute. Delhi university students overwhelmingly live with their parents, and the daily journey matters as much as the institution.
Kreindler, Gabriel. 2024. "Peak-Hour Road Congestion Pricing: Experimental Evidence and Equilibrium Implications." Econometrica 92 (4). A field experiment in Bangalore, paying drivers to avoid congested areas and times. The finding: congestion pricing would produce only modest benefits in Bangalore because traffic density has a relatively moderate impact on speed there, meaning you would have to charge astronomically high prices to shift behaviour significantly.
Jedwab, Remi, and Adam Storeygard. 2022. "The Average and Heterogeneous Effects of Transportation Investments: Evidence from Sub-Saharan Africa 1960–2010." Journal of the European Economic Association 20 (1). Shows how transportation infrastructure investments, including the legacy of colonial railroads built primarily to connect mines to ports, continue to shape where Africans live and how countries trade, with consequences that push African economies toward overseas rather than intra-regional commerce.
More VoxDev Talks on this topic

Michelson, Hope, 2026, “African agriculture's underappreciated supply side.” VoxDev Talk. How transport links are one of the many impediments that stop rural farmers from making the most of the opportunities of better agricultural inputs.
Related reading on VoxDev

"Urban transport infrastructure in developing countries”, the VoxDevLit review of research on urban transport in LMICs, covering buses, BRT, subways, and informal transit networks.
"Who wins when public transit challenges private transit?”, the Lagos bus reform discussed in this episode, with further detail on how informal drivers responded to new public routes.
"Perceived risk of street harassment and college choice of women in Delhi”, Girija Borker's research on how commute safety shapes women's educational choices, as discussed by Storeygard in this episode.
"The equitable benefits of Colombia's bus rapid transit system”, complements the discussion of BRT in Bogota, one of Storeygard's three best-evidenced cases for BRT benefits.

Particulate matter is, Michael Greenstone argues, the greatest public health threat on the planet. Worse than HIV, cigarettes, and alcohol. The average person  loses about two years of life expectancy to it. In India, the figure is three and a half years. The solution to this problem has been tested, and it works, at least in high-income countries.
Greenstone and his co-authors ran a randomised controlled trial in Surat, Gujarat: from 300 industrial plants, mostly making textiles, all burning coal, half were randomly assigned to a market where pollution permits could be bought and sold. The results: in the market, pollution fell 25%, compliance was near-perfect, and abatement costs dropped 12%. The cost-benefit ratio is as high as 200 to one. Many plants in the control group asked to be moved into the market.
The research behind this episode:
Greenstone, Michael, Rohini Pande, Nicholas Ryan, and Anant Sudarshan. 2025. "Can Pollution Markets Work in Developing Countries? Experimental Evidence from India." Quarterly Journal of Economics 140 (2): 1003–1060. An ungated version is available as BFI Working Paper 2025-53.
To cite this episode:

Phillips, Tim. 2025. "Can Pollution Markets Work in Developing Countries?" VoxDev Talk (podcast). 
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About Michael Greenstone

Michael Greenstone is the Milton Friedman Distinguished Service Professor in Economics at the University of Chicago, where he is the founding Director of the Energy Policy Institute at Chicago (EPIC) and the Institute for Climate and Sustainable Growth. His research focuses on the costs and benefits of environmental quality, including the Air Quality Life Index, which tracks the toll of particulate pollution country by country. He previously served as Chief Economist for the President's Council of Economic Advisers under President Obama. 
Research cited in this episode

Air Quality Life Index (AQLI), Energy Policy Institute at Chicago. The source of the life-expectancy statistics used in this episode: particulate pollution costs the average person on Earth roughly two years of life expectancy, with India averaging three and a half years. The index tracks this burden country by country, city by city.
The US sulphur dioxide cap-and-trade programme, established under the 1990 Clean Air Act Amendments, was the canonical precedent Greenstone cited: a market that dramatically reduced acid rain in the eastern United States at costs far below pre-programme projections. He noted that the UK and EU have since built comparable CO2 markets. All have worked well. The question this experiment addressed was whether the same logic held in the developing world, where almost all the pollution now is.
Emissions Market Accelerator. An independent scale-up organisation founded by Greenstone and colleagues to replicate the Gujarat model beyond the original research setting. Current pipeline: a statewide sulphur dioxide market for Maharashtra (including large power plants, not just textiles), and advanced conversations in Pakistan and Brazil. Within Gujarat, a water pollution market is also in development.
More VoxDev Talks on this topic

Regulating pollution in low- and middle-income countries Rohini Pande and Nicholas Ryan, two co-authors of the paper discussed in this episode, on the political economy of pollution regulation in developing countries: why enforcement is hard, and what makes it work.
Air pollution and infant mortality Jennifer Burney on the health costs of particulate air pollution for young children, and what the evidence from Saharan dust patterns across Sub-Saharan Africa reveals about exposure and mortality.
The Social Cost of Carbon Michael Greenstone's earlier VoxDev Talk, on how assigning a monetary value to carbon emissions can drive better policy decisions and make the case for action that regulation alone struggles to make.
Related reading on VoxDev

Reducing air pollution: Evidence from payments to reduce crop burning in India How cash payments to farmers in northern India changed behaviour and cut the seasonal haze from crop fires that pushes Delhi's air quality to its worst each winter.
Paying to pollute: How carbon offsets actually raised emissions in China A cautionary study on market-based pollution controls: when incentives point the wrong way, a market can make things worse rather than better.
The effect of pollution on worker productivity: Evidence from call-centre workers in China Air pollution reduces cognitive performance and output, adding an economic productivity argument to the health case for cleaning the air.

A small number of Asian countries have provided thousands of high-skilled migrants to the US, many of whom have gone on to great success. What created this long-term trend, and what has it contributed to the US economy? And with changes in domestic policy, technology, and the opportunities in other countries, will it continue? 
Gaurav Khanna of UC San Diego tells Tim Phillips the story of high-skilled migration to the US and warns of the consequences for the US economy if, in the future, they decide to go elsewhere – or stay at home.

With the number of global refugees continuing to rise, integrating refugees has become a difficult challenge for hosts – and it is far from easy for the refugees themselves. Dany Bahar of Brown University and Giovanni Peri of UC Davis tell Tim Phillips about a new review of the evidence that evaluates what policies have worked.

In this episode of Ideas in Development, we ask what needs to happen before AI can take off in Africa.
Rose Mutiso talks us through the current state of energy and digital infrastructure in Africa, why leapfrogging is not guaranteed with AI, and what fundamental bottlenecks need to be addressed.
Read the full show notes: https://voxdev.org/topic/technology-innovation/ai-africa-barriers-opportunities-and-policy