Meeting the Future: Cities+Mobility+Built Environment
Changing The Game In Urban Design And Transportation
More than half of the world’s population currently lives in urban areas, with this percentage projected to increase dramatically in coming decades. The health of our planet and its inhabitants depends on developing new strategies for human settlement and activity that foster sustainable outcomes. The SEAS community responds by working to build infrastructure to foster human connectivity.
Nature Pill
20 Minutes: Amount of time needed to experience the benefits of nature.
Taking at least twenty minutes out of your day to stroll or sit in a place that makes you feel in contact with nature will significantly lower your stress hormone levels. That’s the finding of a recent Mcubed study—led by SEAS Landscape Architecture Professor MaryCarol Hunter—that has established for the first time the most effective dose of an urban nature experience. Healthcare practitioners can use this discovery, published in Frontiers in Psychology, to prescribe ‘nature-pills' in the knowledge that they have a real measurable effect.
"We know that spending time in nature reduces stress, but until now it was unclear how much is enough, how often to do it, or even what kind of nature experience will benefit us," said Hunter. "Our study shows that for the greatest payoff, in terms of efficiently lowering levels of the stress hormone cortisol, you should spend 20 to 30 minutes sitting or walking in a place that provides you with a sense of nature."
The Mcubed study builds upon the work of environmental psychologist and SEAS Professor Rachel Kaplan, who along with her husband Stephen Kaplan, published The Experience of Nature: A Psychological Perspective in 1989, a book that influenced how generations of landscape design professionals and environmental psychologists view humanity’s relationship with nature.
Flying Cars
Question: are flying cars sustainable?
Answer: Only fully-loaded, four-occupant electric-powered flying cars for trips longer than 60 miles result in fewer emissions than average occupancy ground-based cars. A single-occupant flying car never outcompetes a single-passenger electric ground-based car.
An interdisciplinary team conducted groundbreaking research to guide the deployment of flying cars from a sustainability perspective before they even go to market. Their paper, entitled “Role of flying cars in sustainable mobility,” was published by Nature Communications, and received extensive media coverage, including write-ups in Popular Science and Forbes.
The research team included two SEAS students—Akshat Kasliwal (MS ’19), first author of the study, and Jim Gawron (MEng ’11, MS/MBA ’19), a dual degree master’s student at SEAS and the Ross School of Business (Erb Institute)—along with Noah Furbush (BSE ’18, MEng ’19), a master’s student at the U-M College of Engineering, and Greg Keoleian, senior author of the study, professor, and director of the Center for Sustainable Systems at SEAS.
The Latest Buzz
Based on their collection of 3,300 bees from 26 sites spanning 70 miles, a U-M-led team of researchers discovered that the more urbanized the environment, the more male-dominated the bee populations tended to be. Their new study, published in the journal Scientific Reports, is the first investigation of observed sex ratio in a complete wild bee community along a rural-to-urban gradient.
A variety of reasons may account for the increase in males—including the males’ freedom to fly farther from the nest to find limited food sources, the lack of available habitat for ground-nesting females, and alternatively, sex allocation by the bees themselves. Male bees, as it turns out, take less work to produce.
Based on their results, the study authors suggest that past research may have been underestimating the negative impacts of urbanization on ground-nesting bees, as well as the importance of considering sex-specific differences in bee behavior.
Study co-author Paul Glaum is a postdoctoral fellow in the U-M Department of Ecology and Evolutionary Biology (EEB).
“Female and male bees of the same species often pollinate different plant species,” said Glaum. “As a result, a decline in female bees has the potential to limit pollination services for part of the plant community.”
The other co-first authors of the Scientific Reports paper are U-M doctoral students Gordon Fitch and Chatura Vaidya of EEB; and Carolina Simao Roe-Raymond (PhD ’17), now at Princeton University.
Cooling Detroit
Urban planners have sought to alleviate “heat islands”—urban areas created by high concentrations of pavement and buildings—with the cooling benefits of green rooftops and other forms of green infrastructure. But a new study, conducted by SEAS alum Lino Sanchez (MS ’18) and Professor Tony Reames, revealed that green roofs specifically were located in the affluent part of Detroit’s urban core, where the population is predominantly white—rather than in those low-income communities that are often without access to green spaces, leading to a greater risk of heat-related illnesses.
In tandem with health issues, energy justice concerns also arise, the study states, when considering the lack of access to air conditioning in disadvantaged communities, or the inability to afford it when available.
A Shortcut Named “Desire”
A new study published for the Landscape and Urban Planning journal identified 5,680 informal footpaths—totaling 157 miles—crisscrossing Detroit’s urban landscape. Blazed by pedestrians seeking shortcuts across vacant lots and public spaces, the footpaths are also known as “desire lines."
Study authors Professor Joshua Newell (SEAS) and Professor Alec Foster (Illinois State University) describe the paths as “creative attempts to expand urban possibilities, enhance efficiency, and reaffirm agency in increasingly regulated cities." The authors found that desire lines in Detroit, however, are rapidly disappearing. From 2010 to 2016, the Lower Eastside region of the city witnessed a 70-percent reduction in the total length of these lines. Their analysis showed that the decrease correlates with changes in land ownership, management practices, and population dynamics.
"A major argument for formalizing and preserving desire lines is to increase neighborhood walkability and mobility," said Newell. "This is especially important in places like Detroit where more than 25 percent of the population do not own cars."
Despite the prevalence of desire lines, especially in post-industrial cities, no comprehensive study of desire lines existed for any urban area before Foster and Newell completed their work. The researchers identified Detroit’s desire lines by combining remote sensing and spatial analysis with physical audits and interviews.