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Walking and cycling dominate urban transport in Asia and Africa. This statement is worth repeating. Walking and cycling dominate urban transport in Asia and Africa. It is one of the key statements in the book "Urban Transport in the Developing World", subtitled "A Handbook for Policy and Practice", edited by Harry Dimitriou and Ralph Gakenheimer. But it is much more than a handbook. It is the most comprehensive overview on the topic. With more than 600 pages, take your time reading it. While there is some redundancy, reading this book carefully will provide you with a superb, encompassing understanding of urban transport in the developing world.

Here is the book's story. 60% of the world's population live in Asia, and Asia is the epicenter of the global urbanization wave. Asia is also the focal point of incredible motorization with China alone being projected to have in 2050 nearly as many cars, as the world has currently on its roads, in totol: 700 million cars. An Asian city also gives its name to one of the key concepts I extracted from the book: the Bangkok syndrome. Similar to their OECD counterparts, Asian and African cities start with dense, walkable city cores. At the beginning of the last century, OECD cities invested in the then upcoming rail-based transport infrastructure, shaping cities profoundly. With the relatively slow but profound rise of automobility, American cities developed into low-density automobile cities, while European cities kept their inner cities served with public transit. Asian and African cities seem to be mostly on a different trajectory: They skip the stage of public transport infrastructures and move directly into individualized motorized mobility. This is too some degree quite surprising: Relative to their GDP, cities of the developing world invest much more into highways, citizens proportionally much more into personal transport than their OECD counterparts do and have done (see e.g. Jeffrey Kenworthy's contribution). Inversely, these developing cities have high population density and are unsuitable for car transport. As a result, especially Asian cities develop into 'motorcycle' cities (Barter, 2000): motorized two-wheelers are best adapt to navigate the traffic disasters, but are subject to high accident rates and still face congestion.

Distribution and accessibility is another, related theme that develops continously across chapters. As the introductary statement indicates, paraphrased from Setty Pendakur's chapter, non-motorized transport is the starting point of analysis, for transport efficiency and transport equity matters alike. Urban transport planning is often technocratically framed as 'apolitical intervention' (Eduardo Vasconcellos), where in fact it is top income segment who by driving their cars consume 10 times more space than the urban poor, consume a largest part of transport energy, and are responsible for most of street-level air pollution. It is then quite clear that a suitable normative objective for urban transport is reasonable accessibility for all, possibly emphasizing the urban poor (the concept itself actually may need to be qualified, see Xavier Godard's chapter). Accesssibility itself is a highly interesting concept: Some cities, such as Dakar, seem to have high accessibililty - walkability - for the poorest quantile. In contrast, in cities like Buenos Aires the lowest income quintile pays proportionally to income much more than the richest quantile. Poverty may also directly reduce social contact by rendering visits to family or friends infeasible.

In line of the this comprehensive analysis, it then follows naturally to require comprehensive assessments of urban transport projects and plans, relying on strategic environmental assessments (Michael Replogle), inclusive equity evaluation (Eduardo Vasconcellos), and context-specific economic appraisal (Walter Hook). The key conundrum, however, is then in the meta-level of institions (Elliott Sclar and Julie Touber). In the dense urban environment of Asian and many African cities, the traffic disaster of the Bangkok syndrome can only be tackled with efficient public transport. But public transport can be regarded as a quasi-public good, and will not emerge from demand-side focussed market outcomes. Hence institutional capacity, a governance framework of promoting public goods and better public transport and non-motorized transport system need to coevolve simultenously. Transport planning alone is not enough.

Planet Under Pressure integrates more than 3000 people of diverse research communities into a four-day conference in London these days. What this conference makes really great is that people from very different disciplines talk to each other and try to get the social and environmental issues together from various angles: demographics, climate change mitigation and adaptation, migration, infrastructures, cities, subsistence farming, and so on.

You can follow the plenary discussion online!

In the demographics session today, the report Migration and Global Environmental Change was presented.

One key insight is that migration, in terms of percentage of total population, remains largely unchanged. Migration is driven by multiple causes, and environmental threats can be dominant in specific cases. Crucially, the report understands migration as adaptation of individuals and households – it does not need to be interpreted as something that needs to be avoided. In fact, more worrisome than migration can be the absence of migration: the poorest part of populations in many cases lacks the (financial) capacity to move around.

Another result of the report is that migration often leads to higher exposure of environmental hazards (e.g. when urbanization increasingly results in migrants occupying land under high flooding risk).

The mismatch between insight on the need for climate change mitigation and implemented policies is amazing. Seemingly, this is a particularly hard global common good problem. So why not push much harder for pure win strategies. Pure win strategies often lack the intelectual appeal of a global cap and trade and, for being so nitty-gritty, put less glory on policy makers. But they can be valuable entry points for global cooperations. Here is one example.

Diesel fuel reserves tax benefits in most Asian countries, and is favored in vehicle regulation. At the same time, pollution control is weak at best. At a result, vehicles powered by diesel emit tons of black carbon in addition to CO₂. Black carbon is the third most gaseous contributor of climate change and has most of its climate impact on short time scales (more like 20 years), whereas CO₂ remains in the atmosphere for more than 100 years in average. Black carbon and other diesel exhaust also pollutes the air breathed by billions of Asians, causing asthma and lung cancer.

Here is the strategy as developed by Minjares and Rutherford (both from ICCT, San Francisco) in the upcoming book "Low Carbon Transport in Asia" by Zusman, Srinivasan and Dhakal:

•  Make particle filter in diesel vehicles mandatory. This can dramatically improve air condition for Asian city dwellers in the upcoming decades. Even more, this single measure can reduce GHG emissions by 14% on a GWP20 basis and by 4% on a GWP100 basis. Not the killer app, but considering the huge health benefits, this is a straight forward measure.
•  Switch to carbon-neutral fuel emission standards (i.e. corporate average, not weight-based, and I would insist, also not size-based). Asian countries can rely here, as well as for pollution control, on the well-established technological advance from OECD countries. No need for R&D investments here.
•  Finally, tax benefits for diesel vehicles can be scrapped, and taxation can follow the GHG content of fuels only.

These measures require some institutional capacities, but not much financial resources from governments. That is probably where industrial countries or the Asian Development Bank can come in with support. But Asian countries profit most, besides climate mitigation, improving public health conditions drastically, especially for the poor, and raising tax revenues simultaneously.  

Developing Asia is at a crossroads, transport-wise. And integrating co-benefits in transport decision-makes the difference. That in a nut-shell is the message of the book Low Carbon Transport in Asia - Strategies for optimizing co-benefits by Zusman, Srinivasan and Dhakal, just getting published at Earthscan.

The book builds on established approaches to quantify co-benefits of sustainable transport benefits. According to perspective, climate change mitigation is a co-benefit of air pollution combat or transport management or, the other way around: a better air quality is the co-benefit of ambitious climate protection. With close to half of the world population living in mostly densely populated Asia, the exposure of transport impact is particularly relevant on this continent - a co-benefit approach will deliver most in Asia. The book, an organized collection of articles around this topic summarizes conceptualization efforts and developes case studies on realizing transport co-benefits. Crucially, the book manages to transcend pure quantification efforts and analyzes barriers to co-benefit strategies and corresponding solution strategies. Zusman et al. identify two main avenues: A) clean and affordable technologies for motorized vehicles that can have huge impact on improving the health of billions of Asians while also substantially reducing non-CO2 greenhouse gas emissions; and B) transport demand management strategies that are even more comprehensive, also addressing congestion, safety, and accessibility issues, but are also more ambitious.

While there is some overlap across chapters, all a well edited and are a very good read. The true value of this book, however, is its success in bringing the transport co-benefit literature together, providing an excellent overview for scientists and policymakers. 

Disclosure: I contributed to this book project.

One of the crucial questions of our time is whether international environmental regimes can and will manage to save the climate and other global environmental commons, such as biodiversity. Oran Young from the University of California, Santa Barbara, provides crucial insights in his meta-analysis, just published in PNAS. Rather than trying to summarize his observations, I aim to highlight a few points.

Interestingly, political scientists judge international regimes systematically more positive than economists, probably reflecting different assumptions and mindsets. Nonetheless, analysts agree there is a full spectrum of international regimes, ranging from the rather successful ones (such as the Montreal protocol on ozone) to the rather unsuccessful ones (such as Kyoto), and many in between. According to a metastudy by Breitmeier et al., international regimes contributed significantly or very strongly in about half of the cases where environmental problems improved. Another observations is that regimes can be successful even in non-hierarchical, non-enforcable circumstances. It turns out that some "easy" problems are systemically messed-up whereas some "hard" problems are surprisingly successful dealt with. Instead, regime design matters a lot: Attention to details can be more crucial then the path chosen (both incentive-based and command and control regulations can lead to success).

Perhaps motivating for the climate issue: a coalition of influential actors can drive a regime towards some sort of success, even if the a single dominant actor remains passive. Fairness and legitimacy are preconditions for success, especially given the mostly non-enforceable character of international regimes. Indeed, Young suggests that we need an understanding of the conditions under which fairness and legitimacy can be productive forces.

Will there be a successful climate regime? We don't know. We can only try. Young suggests some innovative routes that scientists and policy makers should explore.

A broad literature investigates the impact of urban form and transport energy use, clearly demonstrating the benefits of compactness for lowering energy use and reducing greenhouse gas emissions. Myriad qualifications apply, of course, highlighting the importance of street accessibility and job-housing balance (e.g. Ewing and Cervero, 2010).

Ewing and Rong (2010) finally explored the other side of the story: the impact of urban form on residential energy use, relying on US data. Intuitively, sprawled residences have higher space requirement and need more energy for heating. The authors show that single-family detached housing consumes 54% more energy for heating and 26% more energy for cooling than otherwise comparable multi-family housing. With equal income, black, Hispanic and Asian household are more likely to live in multifamily housing than white households do. Multifamily housing is highly correlated with compactness.

The Urban Heat Island effect introduces another dimension. Compact neighborhoods are warmer than sprawled neighborhoods, causing less heating demand but higher cooling demand. The less-heating effect dominates in most regions in the US. The exception is the Sunbelt, where higher temperatures require higher additional cooling demand, creating an energy penalty for more compact housing. With global warming, this energy penalty is likely to increase.

Altogether the housing effect clearly dominates the energy balance. An average household in a compact neighborhood (one standard deviation above mean) consumes 20% less energy than the average household in a sprawled neighborhood (one standard deviation below mean). Let us look forward to seeing other detailed studies on this issue, also from other parts of the world. 

Amazonian deforestation is a major regional and global disaster, rapidly diminishing natural capital, contribution to mass extinction, and to climate change via land-use emissions. Evidently, the drivers of deforestation need to be closely scrutinized. Imori et al. (2011) contribute to this debate and perform an input-output analysis on Amazon deforestation in 2005. They find that cattle, soybean and to lesser degree sugar cane are main culprits of deforestation. The study does not investigate market-mediated effects. For example, the possibility that sugarcane production around Sao Paolo substitutes for cattle, which, in turn, is pushed into the Amazon region is not analyzed (Lapola et al., 2011). The authors point out that cattle and soybean provide employment in a region that otherwise offers few opportunities. Employment and economic growth targets are thus in direct conflict with forest protection. Soybean is mostly exported (e.g. for feeding industrially produced chicken in Germany). From a consumption-based perspective, importing countries of soybean are also responsible for Brazilian deforestation. A relevant CO2 tax on consumption of soybean (and cattle) in OECD countries or on production in Brazil could reduce the pressure on continued deforestation. Global efforts of forest protection are probably well advised to advance approaches that provide high employment and give ownership of forest protection to local communities.

Life-style wise, Berlin is an attractive city. New York hipsters flood some parts of the city, young entrepeneurs create a vibrant high-tech community in Mitte, Berlin's center. A secret of its attractivity lies in history: A number of smaller cities merged into Berlin around 100 years ago, creating a poly-centric structure. Berlin thus consists of numerous relatively quite villages that are well-connected by public transit.

That said, political dynamics point into a different direction. This week, coalition negotations of the upcoming Berlin government between the Social-Democrats and the Green Party flow apart. Reason: The construction of another urban freeway segment. The new and old mayor Klaus Wowereit insists on building more freeway, a condition the Green Party could not accept.

So is there a rational of additional freeway capacity? In the traditional paradigm, freeways and other roads increase mobility, and by this, contribute to economic growth. This paradigm seems obsolete in scientific research:

·          The economic growth framework still exists if only because of lack of alternatives. But the Sen-Stiglitz-Fitoussi report starts to offer a viable alternative.

·           The additional economic growth effect works only for mostly incomplete transport networks, but not anymore for saturated networks (see e.g. Hurlin, 2006). 

·           Road-way capacity induces additional demand, without alleviating congestion (e.g., Noland, 2001).

·          Even for US-cities, a "No-more-freeway" scenario seems to outperform additional urban freeway construction in terms of cost-effectiveness (Zhang and Xu, 2011).

·          Urban motorized transport causes huge social externalities beyond congestion, such as air pollution, noise pollution, inequitable access, accidents, climate change, and increase oil dependence (see e.g., Creutzig and He, 2009).

The Berlin freeway would in addition require the deconstruction of a number of building and take away space from urban gardening ("Kleingärten"). Nonethess, if the freeway would address a significant bottleneck, there could a rational behind the construction. But the most recent study on this issue concludes, that in contrary, the freeway would induce constant congestion in the urban village where it ends, as crossings cannot be adapted to the incoming flow of vehicles. 

Air pollution is commonly measured with immobile detectors attached to buildings. Measured pollution levels do not necessarily relate to the impact of air pollution as experienced on the street. Josh Apte and colleagues addressed the question of air pollution as experienced by commuters by measuring concentration of pollutants in a transportation micro-environment, i.e. in a moving auto-rickshaw in New Delhi.

New Delhi, as other cities in rapidly developing countries, is plagued by chronic congestion and air pollution, producing massive social costs for its inhabitants.

The main results of this study are three-fold. First, measured exposure concentrations are higher in New Delhi than measured before in other megacities. Second, high short-duration peak concentrations, integrated over time of exposure, are a main culprit of the overall high exposure. Third, the total exposure of one commute in an auto-rickshaw approximately corresponds to the total daily exposure experienced by city inhabitants in rich countries.

While New Delhi switched its public bus fleet from diesel to clean natural gas, this seemed to not have been sufficient to reduce air pollution to acceptable levels. In fact, on-street air pollution is likely to even worsen because of increased vehicle ownership an on-going trend to diesel LDV.

The high costs and impacts of air pollution seem to warrant much tighter regulation of vehicle emissions also in developing countries. In addition, enforced parking management and a more comprehensive bus rapid transit system with dedicated bus lanes may not only benefit air quality but increase also transport efficiency.

Read also this blog here, and watch the video tracking on-street exposure.

Since Newman's and Kenworthy's work in 1989, the role of urban density has been controversely discussed as a mean to reduce gasoline consumption. Newman and Kenworthy's results are very suggestive - see figure below: With higher urban density, fuel consumption goes down with 1/x. Numerous studies have confirmed the basic relationship in different settings. However, the causal relationship still remains illusive (note that transport economists have worked on this issue since the 1970ties, but communities use different language and communicaton between communities remains sparse).

A key criticsm affects not the general results but the proper role of control variables that may co-correlate with urban density (e.g. Mindali et al., 2004). Karathodorou, Graham, and Noland recently published a paper that looks more closely on how a number of variables - including urban density - influence fuel demand. They decompose fuel demand into car ownership, fuel efficiency, and distance traveled by car, and look how each of these factors is influenced by urban density. Fuel efficiency seems to be not significantly correlated with urban density, perhaps because stop-and-go efficiency loss of denser urban areas is compensated by smaller cars more suitable for parking in dense urban areas. However, car ownership and transport activity are both significantly correlated to urban density. Using the Millenium Cities Database for Sustainable Transport, the authors find that the elasticity of car ownership with respect to urban density is around 0.12. The elasticity of distance traveled with respect to urban density is around 0.23-0.24.

While these numbers still not reveal causal relationships, this refined analysis sharpens the intuition on the role of urban density. 

Image via Wikipedia