12.11.07
Posted in Science, Transportation
at 11:25 am
This is a follow-up to my earlier post about Monbiot’s book on climate change. In that post, I stated that I was interested in long-term emissions targets because they will probably constrain transportation planning over the course of my career. Now that I’m looking at the issue more closely, I’ve found some relevant research: a great report from Robin Hickman and David Banister in the UK, Visioning and Backcasting for UK Transport Policy or VIBAT. (Reference courtesy of Todd Litman, VTPI.) It looks at the transport problem in the UK through a similar lens as Monbiot, but with considerably more rigour. For the record, VIBAT is not yet published in a peer-reviewed journal, although it has been presented at academic conferences. To date, I have only read the executive summary and skimmed the rest.
Domestic transportation in the UK emitted 39 MtC/year (megatonnes of carbon per year) in 1990, the Kyoto baseline. It rose slightly to 41 MtC/year by 2000, and is projected to rise to 52 MtC/year by 2030 in a “business-as-usual” scenario. A recent Department for Transport white paper suggested new policies for the UK, and projected that the 2030 level would be 38 MtC/year if those policies were adopted, a very small reduction from 1990 levels.
Hickman and Banister took a more dramatic approach. They chose a target of 60% reduction in domestic UK transportation emissions by 2030 from the standard 1990 baseline, aiming for a 15 MtC/year emissions level. This is not Monbiot’s target of a 90% cut by 2030, but it’s still an ambitious choice, somewhat more aggressive than the official UK goal of 60% by 2050.
In the early framing of the paper, the problems of air travel are abundantly clear: UK international air emissions are currently 8 MtC, and might be projected to rise to 20 MtC by 2030. I can’t imagine a scenario where it would be politically acceptable for air travel to be given a bigger slice of emissions than all domestic transportation. As the authors state, “Reducing carbon emissions from international air travel should be a priority for research and action.” In the report, they focus on domestic emissions alone, and leave air travel and international shipping outside their scope.
The authors came up with two scenarios for the policy climate in 2030.
- A “New Market Economy” where the emissions target is met with a minimum of change in behaviour. This is achieved by investing heavily in hybrid vehicles and alternative fuels, and hoping that adequate technology can be developed.
- A “Smart Social Policy” vision where behavioural change is the central strategy instead of technology. Carbon savings are achieved by shorter trips, lower speed limits, and a broad package of policies.
Hickman and Banister assembled a package of policies that would be deployed under each scenario, “backcasting” to find appropriate policies that match the vision. They found that the “New Market Economy” vision could not meet the carbon targets and fell ~10 MtC short, even with optimistic assumptions regarding future technology. The main reason for this was the ongoing growth in car travel: a business-as-usual scenario of +35% in travel would require a massive technological fix. By contrast, the policies that were politically acceptable in the “Smart Social Policy” vision were adequate for the task.
The figures below summarize the emissions changes (in MtC/year) associated with the policies in each package. Click to enlarge and see them side-by-side. (Sources: Fig. 4 and 5, Executive Summary. Resized to matching scales.)
These results don’t particularly surprise me, but it’s still unusual to see a prominent academic like David Banister putting his name beside such a bold policy proposal. Beyond the usual recommendation of further research, the authors do attach one major caveat to their result: they have assumed that the policies they recommended do not interact and result in synergies. That’s a whopper; it’s entirely possible that synergies would result. Finally, I haven’t personally reviewed the assumptions associated with their emissions estimates; I’m sure many of them have a big margin of error. Still, while the exact impact of each policy is unknown, I wouldn’t be surprised if overall conclusion is still accurate: behaviour change will probably be necessary.
One side note tying back to my Monbiot posting, the Smart Social Policy vision required on two enabling measures: higher oil prices (either globally or locally due to taxes) and carbon rationing. I was surprised to see carbon rationing included in mainstream academic discussion, but it is apparently making inroads in the UK. (The main reference seems to be Meyer Hillman and Tina Fawcett’s book, How We Can Save the Planet published by Penguin.)
Finally, here are some pictures that quickly summarize the projections for modal share in the different scenarios:
The size of each box tells you have many kilometers each person is projected to travel using each mode in a given year. This says nothing about emissions, just how far people travel and what mode they use for their travel. I like this visualization: it emphasizes the reduction in travel in the Smart Social Policy scenario. The scales on the left are for the two bars, indicating the carbon emissions and vehicle efficiencies in each scenario. (I’ve made one correction, indicated like [this]: they forgot to include the 10 MtC/year shortfall in the New Market Economy scenario.)
For reference, here are historical modal shares. The 2030 projection shown below represents the white paper policy projection, not the “business as usual” BAU scenario with 52 MtC/year emissions.
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10.10.07
Posted in Science, Transportation
at 4:05 pm
Mike passed me a recent report from the Intergovernmental Panel on Climate Change (IPCC) Working Group III (Mitigation of Climate Change). The IPCC is quite famous for its reports summarising the scientific consensus on climate science, so I was curious to see what the process and results of their follow-up reports looked like. I only read the transport chapter, since it’s the part I understand.
Overall, it’s a decent summary of current understanding of transportation trends, which is difficult to do at an international level with a wide spectrum of urban forms and demographics. The report includes a summary, and working group members vote on each paragraph to establish the level of knowledge and agreement on the report’s conclusions. One paragraph in particular struck me:
Providing public transports systems and their related infrastructure and promoting non-motorised transport can contribute to GHG mitigation. However, local conditions determine how much transport can be shifted to less energy intensive modes. Occupancy rates and primary energy sources of the transport mode further determine the mitigation impact. The energy requirements for urban transport are strongly influenced by the density and spatial structure of the built environment, as well as by location, extent and nature of transport infrastructure. If the share of buses in passenger transport in typical Latin American cities would increase by 5–10%, then CO2 emissions could go down by 4–9% at costs of the order of 60–70 US$/tCO2 (low agreement, limited evidence).
[page 326, emphasis added]
I’m a little shocked that this paragraph garners low agreement and is considered to be backed by limited evidence. (I’ll exclude the final sentence, since I don’t know anything about that particular study.) The paragraph is already weakened by many words indicating uncertainty - “can contribute” … “local conditions” … “could go down” etc. But there isn’t even consensus with the weakened wording. I emphasised the one sentence on density and spatial structure - my personal research interest. Again, I’m astounded that there is still wavering about this subject.
That sentence represents one of the report’s only discussions of urban form. It appears occasionally elsewhere in the chapter, but the framing unfortunately focuses on transportation, and treats land use as fixed - a massive oversight. While there are occasional mentions of the value of “co-ordinating” transportation and land use, these are not quantified and do not make it into the conclusions of the report. There is a separate chapter on housing, but it focuses on building construction and energy consumption, again omitting urban form. As so often in the past, urban structure is forgotten and falls into the cracks between disciplines.
The report sensibly treats the US as a “special case” in the international context, since it’s so low density. (e.g., increasing transit service in many US cities could plausibly increase GHG emissions - if no new riders are attracted but more buses are on the road). But it’s a double-edged sword - it suggests that US cities can continue to follow an auto-dependent path, since the report doesn’t contemplate changing land use.
At the end of the day, though, the main problem is the inconclusiveness of the research - the focus on the exceptional context of the USA has too often limited researchers from observing the clearer trends in other parts of the world. Integrated land use/transport models are still too immature for this type of policy analysis, and international comparison studies remain plagued by data incompatibilities. Finally, the field rarely presents its results in a policy-relevant manner - I have never seen a transportation/land use report that estimated the cost of a policy in terms of US$/tCO2-equivalent. It’s unfortunate - researchers in fields like biofuels are doing a lot of work to estimate greenhouse gas reductions, and their results are immediately relevant to policymakers.
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10.04.07
Posted in Transportation, Toronto
at 8:48 am
At last weekend’s conference for the Canadian Regional Science Association, I presented a paper on Understanding Iterative Proportional Fitting Using Log-Linear Models. At day’s end, I received the Best Student Paper award (in a tie with Marianne Hatzopolous, a Ph.D. student in my lab). Sure, it’s just a small regional conference… but I’m still happy with that outcome.
In other news, we had an interesting tour of Mississauga with former geography professor Gunter Gad. Some of my photos are on Flickr. I’ve visited Mississauga twice on bike in the past year, both times hitting up Port Credit on the waterfront and Square One, the nominal city centre. This conference was at U of T’s Mississauga campus, and I used a combination of GO Transit and cycling to attend. After seeing a broader spectrum of the streets, I’m considerably more pessimistic about the potential for change in travel behaviour or urban form in this city. It’s extremely segregated into residential and non-residential areas, and the pedestrian realm on almost all arterials is utterly bleak. Not bleak in the sense that it’s dangerous or dirty - just extremely monotonous. Given a choice, no one would walk a kilometer along a street like this - and I saw many streets in exactly this style.
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08.07.07
Posted in Transit, Transportation
at 10:50 am
I hope you don’t mind my descent into technobabble for a few moments.
The Toronto Star recently published an interesting article on demand management in the electricity sector in Ontario.
I go back to a speech that Paul Murphy, CEO of the Independent Electricity System Operator, gave back in January. He pointed out that of the 8,760 hours in all of 2006, peak electricity demand in the province only surpassed 25,000 megawatts for 32 hours. At its highest, it reached 27,005 megawatts last Aug. 1.
So we have two options: spend billions of dollars building and operating natural gas plants that can give us an extra 2,000 megawatts 32 hours of the year, or spend considerably less to pay companies that have promised to reduce their electricity consumption by 2,000 megawatts for those same 32 hours of the year.
Already, the government is paying organisations to reduce their demand momentarily during peak crunches. Loblaw grocery stores are cited as an example, and there are apparently aggregator companies that collect together users to create brief demand reductions during peak periods, in return for a payment.
This is not the conventional approach to either supply or demand management. Economists will argue that demand management is best achieved through price increases, not convoluted rebate schemes like the one discussed by this article. If prices fluctuate in response to changes in supply/demand and consumers can easily observe the price they will pay, then high prices during peak periods will automatically discourage consumers (like Loblaws) who don’t really need the power that badly. (Of course, a badly designed/regulated market can lead to manipulations - as California found out when Enron and others took advantage of flaws in its power market.)
That said, the rebate scheme seems to create a sort of two-tier pricing scheme: those who can reduce demand during peak periods effectively get a discount on their annual electricity consumption. Provided that the aggregator schemes allow anyone to join, then anyone can choose to receive the lower rate. Of course, the system may not be as flexible as variable prices, since aggregators probably sign long-term contracts with businesses/residents who are willing to reduce usage - so there’s no room to change your mind on a day-to-day basis. Mind you, given the catastrophic nature of a power grid overload, a bit of advance planning is reasonable. Overall, it’s probably still quite a bit less efficient than proper pricing, and I imagine it’s also susceptible to manipulation, but the idea is somewhat intriguing.
I find this interesting because peaked demand patterns are a central issue in many systems, including the transportation system. Like the power plants, we build our roads to serve peak demand, and are often left with large amounts of unused space during the off-peak. Is there a place, then, for this type of demand management in the transportation world? Suppose a municipal government faced two options: expanding a freeway (for several billion dollars), or reducing demand. Given the discretionary nature of many peak period trips - and particularly the discretionary nature of peak period mode choice - there is substantial potential for demand reduction.
Unfortunately, there is a key difference between the electricity system and the road system: monitoring. If a consumer signs a contract to reduce power consumption, an outside agent can observe the consumer’s home/office and ensure that power consumption was reduced during the peak period. The same does not apply for driving: if a comparable contract was signed to guarantee that a traveller did not drive during the peak period, there is no reasonable way for an outside agent to observe a person and ensure that s/he complied. The only mechanism that exists for ensuring compliance is removal of the driver’s license, which is far too blunt - it prevents off-peak driving completely.
In some ways, we treat the transit system as a sort of demand aggregator - we charge transit with attracting people off the roadways, and justify subsidies to transit on the basis of relieving peak demand on the roads (in addition to its many other roles, such as citybuilding or providing access to those unable to drive). And while it can have that effect, the connection between subsidising transit and reducing peak roadway demand can be somewhat indirect. The subsidy’s effect (improved transit service and lower fares) do influence travellers’ decisions, naturally, but those improvements can be indirect and fluctuate over time.
If there was a more subtle instrument - an “off-peak only” driver’s license, for example - then society could direct subsidies to individuals who choose to forego the right to drive at peak period, and potentially forego costly expansion of the road system. While this subsidy might sound like it would be expensive, it could be introduced simply as a price differential - a high price to obtain a “peak” driver’s license, and a low price to obtain an “off-peak” license.
For the moment, we have vehicle registration fees, which are a little more blunt as a policy instrument since they penalise all driving rather than simply charging for peak-period driving. Of course, given that society incurs a cost to provide infrastructure for off-peak driving, it is fair to charge some fee to all drivers - but the overbuilding of our roadways is probably more closely linked to peak period demand than off-peak demand.
There is already one extremely sensitive policy instrument: fluctuating parking fees, which have the advantage of adjusting according to local conditions, and varying throughout the day. However, the influence of parking fees can be reduced by other factors, such as bundling with housing or office space, subsidy by employers, and oversupply through municipal regulations.
At any rate, this is all just a brief thought experiment on my part, with no real research involved. I’ve never heard of any proposals for “off-peak licenses” before, but perhaps they warrant consideration.
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