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Julie Rozenberg's picture
Photo: Alex Wynter/Flickr




Bianca Bianchi Alves's picture
Photo: Lazyllama/Shutterstock



Are hybrid and electric buses viable just yet?

Alejandro Hoyos Guerrero's picture
Photo: Volvo Buses/Buses Fan
Hybrid and electric buses may be the future of public transport. But today, they are costlier than their diesel equivalents. Therefore, their implementation requires that private operators be subsidized, or that the higher costs for public operators be covered. For now there are more efficient alternatives for reducing GHG and local emissions.

The most significant emissions reduction will not come from the vehicles; it will come from people leaving their cars at home.

Let’s take the example of a Mexican commuter who chooses whether to ride a bus or drive to work each morning. If she drives, her commute will generate 8kg of CO2, vs. only 1.5kg when riding a diesel bus. By making the greener choice, she is saving up to 6.5kg of CO2. With a hybrid bus, that same ride would emit 1kg of CO2, and zero emission with an electric (assuming zero-emission grid)—translating into additional savings of 0.5kg and 1.5kg over a diesel bus, respectively. The extra savings are welcome, of course, but they pale in comparison to the emissions reduction generated by shifting from a private car to a public bus.

If we analyze a whole system instead of an individual, technology’s potential to reduce emissions gains importance, but is still lower than that of modal shift. That means we first need to focus on providing incentives for drivers to leave their cars behind and turn to public transit. When a bus system with exclusive lanes opens, for instance, 1%-5% of passengers are likely to be new riders who used to drive and made a conscious decision to switch. This proportion can increase to 10-15% with the right ancillary interventions, such as providing non-motorized transport infrastructure, improving accessibility and service quality.

Another great source of emission savings is a more efficient system. We have seen reductions of up to 30% in vehicle-kms after a system reorganization. The following graph compares the potential emission reductions of modal shift and fleet rationalization by shifting vehicles to hybrid (left column) or electric (right column) technology.

Beyond ribbon-cutting: measuring the real impact of transport projects

Nancy Vandycke's picture
Photo: World Bank/Flickr
Development practitioners often rely on Monitoring and Evaluation (M&E) performance indicators to assess the results of a transport project. Collecting indicators before, during, and after a project allows us to gain insights about project execution and project outputs, which can help us, for example, measure changes in travel time or Bus Rapid Transit (BRT) system ridership. While this approach is important, well anchored into project design, and quite practical, it is not intended to evaluate “impact”. Observed changes in outcomes cannot be attributed to the project: many other external factors, such as economic conditions, interrelated policies or projects, or seasonal trends, also come into play. In other words, a descriptive approach fails to establish causality between a project or intervention and subsequent outcomes such as changes in income, labor markets, quality of life, or market efficiency.

To overcome the limitations of traditional M&E, the development community is increasingly turning to impact evaluation, an alternative approach whose methods more directly address the issue of causality. In that context, the World Bank’s transport experts have partnered with colleagues from the Development Impact Evaluation (DIME) team to rethink the way the impact of transport is measured. Two years ago, with support from the UK Department for International Development (DFID), a transport-dedicated impact evaluation program was launched: “IE Connect for Impact”. Now, impact evaluation is being implemented on 10 projects, covering rural roads, urban mobility, transport corridor development, and road safety. More projects will be selected toward the end of the year, as part of Phase II of the program.

The expected benefits are clear: informing project delivery during design and implementation, documenting the effects of policy and investment interventions, and prioritizing and filling knowledge gaps in the sector. Despite these significant benefits, transport accounts for less than 1% of all impact evaluation work —a very low proportion compared to the weight of other sectors such as in health (65% of all published impact evaluations), education (23%), agriculture and rural development (10%), or water (4%).

Are roads and highways the Achilles Heel of Brazil?

Frederico Pedroso's picture
Also available in: Português
Photo: Ricardo Giaviti/Flickr

The “plastic bridge”: a low-cost, high-impact solution to address climate risk

Oliver Whalley's picture
Also available in: Français
Photo: Anthony Doudt/Flickr
Bridges are critical links in the transport network. In their position across waterways, they are exposed to the full effects of flooding and landslides, and are often the first pieces of infrastructure to be damaged in the event of a disaster. They also typically take weeks or months to repair.  Besides causing expensive damage to the infrastructure itself, disruptions in connectivity also have a much broader impact on economic productivity and people’s ability to access essential services. As many places are expected to witness more intense and frequent rainfall as a result of climate change, the risk to bridges will only worsen: more rainfall will lead to bigger river flows and more damage to bridges, especially those designed to handle smaller storms.

At each end of a bridges is a structure which supports the weight of the deck. These are known as abutments, and they are often the first part of the bridge to fail. Blockage of the main channel by debris can cause water to look for the path of least resistance around the sides of the bridges, thus placing the abutments at risk.

Traditional bridge construction requires the installation of piles for the foundations of abutments—a lengthy and expensive process that involves specialist materials, skills and equipment.

But there is another promising solution: Geosynthetic Reinforced Soil (GRS) abutments. These allow for rapid and resilient construction of bridge abutments using locally available materials, without specialized equipment. With GRS, bridges can be constructed in as little as five days (Von Handorf, 2013) and at a cost 30-50% lower than traditional approaches (Tonkin and Taylor, 2016) .

GRS abutments are based on ‘geogrids,’ a high density mesh made out of polyethylene (plastic). Layers of soil and geogrid are combined to create a solid foundation for the bridge deck. Construction can be completed with basic earthmoving and compaction equipment, and a range of local fill materials can be used with guidance from geotechnical specialists.

Climate change is forcing us to reinvent rural transport for the better

Ashok Kumar's picture
Photo: Ravisankar Pandian/Flickr



How have recent bus reforms changed accessibility in Bogotá?

Camila Rodriguez's picture
Photo: Galo Naranjo/Flickr
  • Services were contractualized via concession arrangements
  • The overall number of buses on the roads was reduced
  • Bus routes were reorganized
  • Old buses were replaced with a more modern fleet
  • Cash payment gave way to a smartcard system
  • The city applied stricter quality control, regulation and enforcement.

Is it too early to agree on SDG indicators for transport?

Muneeza Mehmood Alam's picture




A new partnership to enhance the climate resilience of transport infrastructure

Shomik Mehndiratta's picture
Photo: Norsez Oh/Flickr