Evaluating the impacts of the Dar es Salaam bus rapid transit system

Publication Details

3ie Funded Evaluation, DPW1.1029. A link to the completed study will appear here when available.


Author
Melanie Morten,Bilal Siddiqi, Clare Balboni, Gharad Bryan, Yonas Mchomvu
Country
Tanzania
Region
Sub-Saharan Africa (includes East and West Africa)
Sector
Transportation
Subsector
None specified
Gender analysis
Yes
Equity Focus
None specified
Evaluation design
Randomised Control Trials (RCT)
Status
Ongoing 3ie Funded Studies
3ie Funding Window
Development Priorities Window 1

Synopsis

This study estimates the impacts of the first phase of the bus rapid transit (BRT) system  infrastructure and services on commute times, employment status, income, migration, and housing outcomes in Dar es Salaam.

Context

Africa is witnessing growth in urban populations, resulting in increased travel times due to an influx of people. Labour and goods markets that city dwellers can access are also shrinking to the areas closest to where they live. There is a growing pressure to upgrade transport options, however the best approach is unclear.

The Government of Tanzania, under the Prime Minister’s Office of Regional Administration and Local Government , has begun large scale investments in a BRT project in Dar es Salaam. The BRT system has six planned phases, and the first phase was constructed in late 2015. The impact evaluation is expected to inform the implementation of the other phases of the BRT.

Research questions

The impact evaluation will answer the following question:

  1. What is the impact of the BRT system on socio-economic factors of housing, employment, and mobility in Dar es Salaam?
     

The evaluation will also look at the impact of subsiding travel on the  BRT and will address the following questions:

  1. Can short term incentives induce people into regularly using the BRT?
  2. Do short term subsidies lead to long term changes in commuting behaviour?
  3. How does a change in market access brought about by a short term travel subsidy affect employment status, earnings, education, asset levels, consumption and socio-economic status?

The evaluation will also experimentally subsidize rents for some people living along the BRT to assess the following:

  1. How does being displaced because of rising rents change employment status, earnings, education, asset levels, consumption, and socio-economic status?
  2. What are the costs of the BRT in terms of displacing people (this estimate will be derived from a combination of the experimental treatment effect of displacement and the triple difference based estimate of the extent of displacement)?
  3. To what extent can complementary interventions, such as rent subsidies, redistribute the costs of the displacement?

Methodology

Intervention design

The BRT system is a high capacity transport solution which functions in a way very similar to a tramway, except that the vehicles used for transporting passengers are buses. The phase 1 of the BRT system consists of 20.9 kilometers of trunk lanes, 57.9 kilometers of feeder routes, 5 terminals, 27 stations, 7 feeder stations, 3 connector stations, and 2 bus depots. The trunk lanes are exclusive bus lanes at the centre of major roads, and uses feeder buses which operate on mixed traffic lanes to feed passengers to the trunk system. The BRT system is closed; passengers need to access stations and terminals through turnstiles.

Theory of change

It is intended that the BRT’s impacts on commuter travel times and urban congestion will have positive impacts on a range of economic, social and environmental indicators.

First, a location that is close to the BRT line will see improved access to the labour market. Second, consumers living in areas close to the BRT line will see an increase in access to goods markets, making the area a more desirable place to live, and reducing the time spent in daily chores. Third, firms that locate close to the BRT will have greater market access, because more people will be able to access their services. This will tend to increase the amount of firms in the area. Overall, these three forces will lead to a potential increase in land prices, change in land uses and change in the mix of people living in the area.

Evaluation design

The study uses spatial triple differences (difference-in-difference-in-differences) empirical approach.  A baseline household survey was conducted prior to any rollout of BRT services but after final construction of the BRT phase 1 infrastructure. It covered households in clusters at equal intervals along 12 arcs defined at increasing radii from the centre of Dar es Salaam. Two follow-up endline surveys will cover those same households at the same locations and track those that have moved. 

A single general equilibrium model that captures the impact of changes in market access with a key aim of elucidating and quantifying these heterogeneous impacts across different locations and individuals will be estimated.

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