Center for Earth Systems Engineering and Management

While the definition of sustainability remains open for all to contribute to and participate in, there do seem to be some notions it has come to embody that should not be neglected as the definition coalesces. Among these are the ethical and social dimensions of sustainability. Whether or not it is appropriate, required, or even desirable, concepts like social equity, human rights, ethical sharing of commons, etc. have increasingly come under the umbrella of the sustainability discourse. Even if “sustainability” as a bare word doesn’t imply those things, the concept of sustainable development certainly has taken on those dimensions. That sustainability might be redefined or re-scoped to be a purely environmental or a rigidly scientific endeavor, is not an immediate concern of this paper, though if that were to occur (whether for the sake of simplicity or pragmatics), it should be done explicitly so the ethical sub-discourse can be maintained (indeed, sustained) by some other movement.

This paper proposes a mechanism by which such a migration in terms can be prevented. First, in reviewing the work of Denis Goulet, it shows the solid basis for including an ethical aspect in the sustainability discourse. Second, it points out that Karl-Henrik Robèrt’s highly-lauded and broadly-employed sustainability framework, The Natural Step, is deficient in this area. This deficiency provides the impetus for, finally, proposing a mechanism by which The Natural Step can be extended to include the important social and ethical dimensions of sustainability. This mechanism is based on the capabilities approaches that, in many respects, evolved out of Goulet’s early work. Augmented accordingly, TNS can continue to be used without fear of overlooking the social and ethical aspects of the sustainability discourse.

The leading source of weather-related deaths in the United States is heat, and future projections show that the frequency, duration, and intensity of heat events will increase in the Southwest. Presently, there is a dearth of knowledge about how infrastructure may perform during heat waves or could contribute to social vulnerability. To understand how buildings perform in heat and potentially stress people, indoor air temperature changes when air conditioning is inaccessible are modeled for building archetypes in Los Angeles, California, and Phoenix, Arizona, when air conditioning is inaccessible is estimated.

An energy simulation model is used to estimate how quickly indoor air temperature changes when building archetypes are exposed to extreme heat. Building age and geometry (which together determine the building envelope material composition) are found to be the strongest indicators of thermal envelope performance. Older neighborhoods in Los Angeles and Phoenix (often more centrally located in the metropolitan areas) are found to contain the buildings whose interiors warm the fastest, raising particular concern because these regions are also forecast to experience temperature increases. To combat infrastructure vulnerability and provide heat refuge for residents, incentives should be adopted to strategically retrofit buildings where both socially vulnerable populations reside and increasing temperatures are forecast.

There is increasing evidence that vehicle travel in developed countries may have peaked, contradicting many historical travel demand forecasts. The underlying causes of this peaking are still under debate and there has been a mobilization of research, largely focused at national scales, to study the explanatory drivers. There is, however, a dearth of research focused at the metropolitan scale where transportation policy and planning are frequently decided.

Using Los Angeles County, California, as a case study, we investigate the Peak Car theory and whether social, economic, and technical factors, including roadways that have become saturated at times, may be contributing to changes in travel behavior. After peaking in 2002, vehicle travel in Los Angeles County declined by 3.4 billion (or 4.1%) by 2010. The effects of changing fuel prices, fuel economy, population growth, increased utilization of alternate transportation modes, changes in driver demographics, income, and freight are first assessed. It is possible, and likely, that these factors alone explain the reduction in travel. However, the growth in congestion raises questions of how a constricting supply of roadway network capacity may contribute to travel behavior changes.

There have been no studies that have directly assessed how the maturing supply of infrastructure coupled with increasing demand affect travel behavior. We explore regional and urban factors in Los Angeles to provide insight into the drivers of Peak Car at city scales where the majority of travel occurs. The results show that a majority of the decline in VMT in Los Angeles can be attributed the rising fuel prices during the 2000s. While overall roadway network capacity is not yet a limiting factor for vehicle travel there is some evidence that suggests that congestion along certain corridors may be shifting some automobile travel to alternatives. The results also suggest that the relative impact of any factor on travel demand is likely to vary from one locale to another and Peak Car analysis across large geographic areas obscures the nuisances of travel behavior at a local scale.