Restaurant music actually affects what you order, study finds
A new study has found that music volume has a significant impact on people’s food choices, and when soft music is playing in the background of a restaurant, people prefer healthy options like salads.
More and more marketing tactics are revolving around ambiance and studies have shown how big a role music plays in a customer’s overall experience.
Retail atmospherics, as it’s called, is gaining popularity and becoming an important strategic tool for businesses.
Now, researchers from the University of South Florida found that music volume directly impacts heart rate and influences food choices.
The study was published in the Journal of the Academy of Marketing Science.
Loud music drives customers to choose unhealthy options like burgers and fries because the volume raises heartbeat and stimulation.
Quiet music, on the other hand, promotes relaxation and customers are more mindful of their food choices.
For the study, the researchers, led by University of South Florida marketing professor Dipayan Biswas, conducted two field experiments in a cafe in Stockholm.
The cafe played music at two different decibels, either 55 or 70. Fifty-five decibels is similar to quiet background talking or the hum of a refrigerator.
Menu items were categorized as healthy, non-healthy, and neutral, and the researchers recorded what customers ordered over several days to see how the difference in volume impacted orders.
When the volume was turned up to 70 decibels, 20 percent more of the cafe patrons ordered something categorized an unhealthy.
The study adds to the growing body of research on atmospherics which shows how restaurants and stores can influence customers choices and spending.
“Restaurants and supermarkets can use ambient music strategically to influence consumer buying behavior,” Biswas said.
Fit people have different physical responses to food, study finds
Obesity is at almost epidemic proportions in places like the United States, Mexico, and the United Kingdom. It’s a health crisis that costs the global economy about US$2 trillion per year. In fact, the risk factors connected to a poor diet contribute to more disease than unsafe sex, drugs, alcohol, and tobacco use combined.
A great deal of research has focused on how our food environment and neurobiology can result in overeating. It’s known that highly palatable foods such as pizza and chocolate cause signals in the brain that give a feeling of pleasure and reward. However, not much is known about whether or not these responses to food cues support weight-loss maintenance. Now, a new study from the University of Birmingham and the University of Amsterdam has found that successful weight loss maintainers have different behavioral and physiological responses to food than people with obesity and those who consistently stay lean.
The findings of this study suggest that decreased sensitivity to rewarding and highly palatable foods as a result of a reduced physiological response could help explain why some people can lose weight and keep it off easier than others.
The research team compared the responses of three groups: successful weight-loss maintainers who were previously obese, individuals who are currently obese, and individuals who have never been overweight. They looked at the saliva production and heart rate of individuals in each group following exposure to pizza. The results showed that individuals with obesity had increased salivation and a faster heart rate response after exposure, while salivation and heart rate of weight-loss maintainers decreased, and the lean participants were unresponsive.
Study participants also had to complete cognitive tasks to objectively measure their motivation to win and avoid losing food and money in a computerized task, where they had to determine the meaning of a symbol by trial and error. For each trial, they chose one of two figures. The figure either meant that they won food, lost food, won money, or lost money. As the trials went on, participants eventually learned what a specific symbol meant, and their ability to win or avoid different rewards was measured.
Results showed that the ability of weight-loss maintainers to determine the meaning of the symbol was less affected by food “wins” and more affected by food “losses.” The researchers believe this suggests that explicit food rewards hold less value for weight loss maintainers.
“Our findings reveal a marked difference in physiological reactivity to food depending on weight-loss history,” the authors explain. “Further longitudinal research is needed to determine whether reduced physiological response to palatable (high calorie) food and sensitivity to food rewards may be predictive of individuals that can successfully restrict food intake.”
Although no definitive conclusions can be made from this observational study, this vein of research may lead to a better understand of the physiological systems that hinder people who are trying to lose weight. Ultimately, it may lead to better weight loss programs and more efficient dieting plans.
How the ivory trade impacts commercial paleontology
Commercial paleontology can quickly drift into moral grey areas. Many people question the practice of selling fossils for profit at all. I would counter this by saying that museums also sell and buy fossils, and targeting commercial dealers artificially divides industry from academia. In fact, museums are often clients of commercial companies I’ve worked for.
Having worked in commercial paleontology for years, I have found that most in the field are able to distinguish scientific valuable finds from those less useful, and target academic organizations to acquire those fossils beneficial to science. I’m also a bit hesitant to let government decide how people will deal with everything discovered on private land, as public land is completely out of the reach of law abiding commercial paleontology. Personally, I feel public land should remain public in all aspects.
Ivory plays an interesting role in the debate over commercial paleontology. In a business showroom I recently visited, enormous tusks arch in simple metal stands. Other tusks are intricately carved with leopards and mammoths. The tusks are mammoth tusks, but if they were from animals killed by humans, the killing happened before recorded history.
But how to distinguish mammoth ivory from elephant ivory? Some states, including California, have banned the sale of fossil ivory such as mammoth ivory to completely avoid mistaking elephant ivory for mammoth ivory. The law in California was challenged in court by the Ivory Education Institute in November 2016, but was ultimately was upheld by the Los Angeles Supreme Court.
The non-profit Ivory Education Institute argues that elephant ivory trade is already blocked by international treaties and that the California law is ‘superfluous’. The Institute says that banning ivory trade of all kinds won’t stop poaching, and a list of historical bans that failed is cited. Prohibition didn’t stop Americans from drinking, the war on drugs hasn’t stopped us from getting high, etc. The Ivory Education Institute argues that the only way to stop poaching for ivory is for demand to be met through normal, legalized trade.
It seems there may be some truth to the idea, if a small one. In states like Alaska, where fossil ivory is plentiful, you can buy pieces of jewelry featuring mammoth ivory for relatively cheap. The Ivory Education Institute goes on to argue that making ivory illegal increases scarcity, which in turn makes the existing ivory more valuable, increasing the incentive to poachers. Diamonds come to my mind, naturally rather plentiful, some companies hoard diamonds, creating artificial scarcity and inflating their value.
Keeping in line with legalized trade, the Ivory Education Institute goes further; saying ivory is a natural resource. Outsiders are painted in this light as those who impose their own values on how Africans would utilize their ‘resources’. This is the most sickening part of the Ivory Education Institute’s argument.
Elephants are living animals. If someone was torturing an animal for sick pleasure, I would not pause to try my best to stop them. Outsiders imposing bans on ivory in Africa is in some ways harkening back to imperialism. The international ban on ivory though, is more like the ban on human trafficking: a moral imperative. Further, banning the trade of ivory in the US or in California specifically says nothing about what Africans do in Africa. The truth is that different African nations have taken different approaches, such as Zimbabwe’s attempt to create a sustainable ivory trade. Of course, without the ability to export ivory, what is done in Zimbabwe or South Africa is of limited use for their own trade.
Others have argued quite forcefully that legal trade in ivory, or indeed, in anything, fosters a black market. If any ivory is legal, it creates the problem of verifying the status of any ivory, opening the door again to poachers.
The Ivory Education Institute has a point, though; few legal bans have created lasting change. For lasting change, we may look at something else: how views change. At one point, birds were at the whim of the fashion industry. During America’s Gilded Age, hats, pins and other fashion items featuring feathers or sometimes entire birds were the height of women’s fashion. Plume hunters that killed wild birds for their feathers made quick cash for their trade, with little care for the negative aspects. At least one early wildlife ranger was murdered for trying to protect birds from gangs of plume hunters. It’s estimated that in 15 million birds were killed for their feathers.
Wildlife refuges, including those protected by rangers to the death, were partially established to give birds a chance to survive in the face of plume hunting. Bird City, a private reserve in Louisiana by Edward Avery McIlhenny, Tabasco Sauce heir, was established partially in response to plume hunters nearly wiping out Snowy Egrets. Some surviving Snowy Egrets were taken to Avery Island where the refuge was located and introduced first through an aviary and then set free so they could continue their migration.
Acts by the government and private individuals such as Avery did something more important than give birds safe breeding grounds. Slowly through, public acts of compassion toward wild birds through pamphlets blasting the trade in feathers and speeches, things changed. What ended up saving birds like the Snowy Egret wasn’t so much a ban in the feather trade. Laws, such as the 1900 Lacey Act prohibiting transport of birds across state lines that were killed in violation of state laws, didn’t stop the feather trade. What happened is that slowly American women had a collective change of heart. Culture changed. It’s not just feathers either, it’s the fur trade as well. Furs are still sold even if they’re often socially taboo.
The stance of The Ivory Education Institute is repulsive, not so much because it doesn’t have a certain logic to it. I find the argument that ivory is a natural resource disgusting but it isn’t surprising. Conservationists talk of trees, rocks, minerals, fossils even hunted animals as ‘resources’ all the time. The problem is viewing elephants, trees and even the Earth as a thing. This is a problem that we must fix in the ‘hearts and minds’ of every person in the world. We must collectively learn empathy and compassion for others and for the earth itself.
Cigarette smoke even damages the muscles in your body
A new study from The Physiological Society has revealed that smoking cigarettes causes muscle damage. The researchers found that components of cigarette smoke reduce the number of small blood vessels that bring oxygen and nutrients to muscles in the legs.
The findings of the study suggest that smoking damages muscles in the body not only indirectly, but also directly. Prior to this study, smoking was believed to cause muscle weakness indirectly due to the fact that lung capacity becomes more limited, as does an individual’s ability to exercise.
But now, the researchers have demonstrated that cigarette smoke causes direct harm to muscles by reducing the number of blood vessels in leg muscles, which subsequently reduces the amount of oxygen and nutrients that can be received.
This damage has an impact on both metabolism and activity levels, leading to an increased risk for many chronic diseases including diabetes and chronic obstructive pulmonary disease (COPD).
For the investigation, a team led by the University of California, San Diego exposed mice to cigarette smoke for eight weeks. Some of the mice inhaled the smoke, while others were injected with a solution containing tobacco smoke.
Study lead author Ellen Breen is an expert in Respiratory Medicine at UC San Diego.
“It is vitally important that we show people that the use of tobacco cigarettes has harmful consequences throughout the body, including large muscle groups needed for daily living, and develop strategies to stop the damage triggered by the detrimental components of cigarette smoke,” said Breen.
While the study did not identify which of the thousands of chemicals in cigarette smoke are responsible for direct muscle damage, this will be an important focus for further research. The experts also hope to get a better understanding of how these chemicals lead to fewer blood vessels.
The research is published in The Journal of Physiology.
Most people do not say thank you, study finds
A recent investigation into language and social interaction has revealed that people around the world do not usually say ‘thank you’ when someone helps them out. The findings of the research indicate that there is a universal willingness to cooperate.
Study lead author Nick Enfield is a professor of Linguistics at the University of Sydney.
“Our findings indicate a widespread assumption that saying ‘thank you’ is not necessary in the everyday contexts of our lives,” said Professor Enfield.
“Some might interpret this as a crisis of rudeness, that we are polite in public but have no manners in our own homes. But that is the wrong interpretation. Instead, it demonstrates that humans have an unspoken understanding we will cooperate with each other.”
The team analyzed nearly 1,000 recordings of informal conversations among friends, families, and neighbors. The conversations were spoken in eight different languages, including Russian, Polish, and English.
Cooperation was found to be very commonplace, but saying thanks was not. Across most of the languages, gratitude was only expressed vocally in one out of 50 situations.
The highest rates of spoken gratitude expression were found among English and Italian speakers. However, while ‘thank you’ and relative terms were used the most frequently in English, these phrases were still only uttered 14.5 percent of the time.
In Cha’palaa, a language spoken in Ecuador, the speakers never said ‘thank you.’
“When people think of social norms around gratitude, they naturally think about our interactions in formal settings, where it seems standard to say ‘please’ and ‘thank you’,” said Professor Enfield.
“But in in our homes and villages – where our interactions would seem to matter most – we find people dispense with these niceties almost entirely.”
The study is published in the journal Royal Society Open Science.
Endangered delicacy: Earth’s biggest amphibian disappearing
The Chinese giant salamander is one of the more prehistoric-looking animals that is still around today. These ancient creatures – dating back 170 million years – are amphibians that can grow up to six feet long and weigh 140 pounds. They’ve been depicted in Chinese culture for thousands of years, but have now become a highly coveted delicacy amongst the country’s wealthy. As a result, they have all but disappeared from their freshwater habitats.
In order to keep up with growing demand, these amphibians are routinely harvested from the wild in an effort to stock commercial breeding farms. China has officially banned the harvesting of wild giant salamanders, but supports widespread releases of farmed salamanders as a conservation effort. But this conservation measure may actually be harming wild populations by mixing genetic lineages and facilitating the spread of diseases.
Recently, a research team from the Zoological Society of London (ZSL) conducted a wide survey of river sites where the salamanders are known to live. These field surveys covered 97 sites in 23 Chinese provinces through a period of four years.
“We cannot confirm survival of wild Chinese giant salamander populations at any survey sites,” the authors say in Current Biology. “And consider the species to be extremely depleted or functionally extinct across the huge surveyed area.”
The researchers warn that these amphibians are in “catastrophic” decline, with only a handful potentially left in the wild. The species is already categorized as critically endangered in the International Union for Conservation of Nature Red List of Threatened Species.
“The over-exploitation of these incredible animals for human consumption has had a catastrophic effect on their numbers in the wild over an amazingly short time-span,” says Dr. Samuel Turvey, a member of the research team from the ZSL. “Unless coordinated conservation measures are put in place as a matter of urgency, the future of the world’s largest amphibian is in serious jeopardy.”
The salamander population has experienced a dramatic decline in the last few decades as a result of poaching and habitat destruction. But despite their status as an endangered species, this amphibian is still widely regarded as a delicacy. Luckily, recent legislation by the Chinese government has made it so anyone found to be eating this salamander could receive a jail sentence of up to ten years.
Co-author Dr. Fang Yan, from the Kunming Institute of Zoology, laments “It’s essential that suitable safeguards are put in place to protect the unique genetic lineage of these amazing animals, which dates back to the time of the dinosaurs.”
Confronting nightmares can be good for your health, experts say
Nightmares can be so unsettling that they can disrupt a night’s sleep and stay on your mind throughout the following day. While being jarred awake in the middle of the night from frightening dreams can actually cause health issues, experts also say that confronting nightmares can be beneficial.
A new report published in Time examines the health problems associated with nightmares as well as the positive benefits of working through nightmare-related trauma.
The sleep loss associated with chronic nightmares, which is classified as having one nightmare per night, can increase the risk of heart disease and depression.
“When you have a lot of nightmares, that can lead to stress and insomnia,” Michael Nadorff, an assistant professor of psychology at Mississippi State University, told Time. “For people who have significant nightmare problems, it’s also common is for these individuals to actively try to avoid sleep in order to avoid having nightmares. When they do have [a nightmare], they often don’t sleep for the rest of the night.”
However, nightmares aren’t always a bad thing, and dream therapy, or working through the scenarios in nightmares that cause distress, can actually be quite therapeutic.
For example, one study found that nightmares may actually be a coping mechanism and help with stress management.
Working through nightmares can also help with anxiety, as dreams often reflect concerns or emotional turmoil.
Tore Nielsen, a professor of psychiatry at the University of Montreal, told Time that working with a therapist to analyze your dreams can help shed insight into personal fears.
With the health problems associated with sleep deprivation and nightmares, it’s important to look into treatment rather than simply trying to avoid nightmares all together, which can aggravate issues and increase health risks.
There are several treatment options, including taking blood pressure medication or talking through the nightmare with something called image rehearsal therapy.
“We have the person talk through their nightmare and change it in a way that’s not threatening, and then they practice the new dream during the day using visual imagery,” Nadorff told Time. “This kind of daily rehearsal can help reshape the scary dream even while a person is sleeping.”
Nightmares can range in severity from being a mere nuisance to being seriously life-disrupting, but the underlying stresses, fears, and concerns presented in nightmares are often reflections of deep seeded issues that should be addressed.
This is why nightmares, while scary, are not worth ignoring, especially when confronting nightmares could help with stress management, processing trauma, and reducing the health risks associated with nightmare-related sleep deprivation.
Couples who eat seafood have more sex and get pregnant faster
Researchers have found that couples who eat at least two servings of seafood each week are more sexually active and succeed in getting pregnant faster.
The link between seafood and faster conception was not entirely explained by more frequent sex, suggesting that biological factors such as semen and embryo quality are positively influenced by eating fish.
Although seafood is an important source of nutrients for women who may become pregnant, concerns about mercury have led some women to stop eating fish while trying to conceive.
According to the Environmental Protection Agency, 90 percent of seafood consumed in the United States is low in mercury and is safe to eat.
Two to three servings of seafood per week are recommended by the Food and Drug Administration, yet half of pregnant women do not consume this much fish.
“Our study suggests seafood can have many reproductive benefits, including shorter time to pregnancy and more frequent sexual activity,” said study co-author, Audrey Gaskins.
“Our study found that couples who consume more than two servings of seafood per week while trying to get pregnant, had a significantly higher frequency of sexual intercourse and shorter time to pregnancy.”
The investigation was focused on 500 couples from the Longitudinal Investigation of Fertility and the Environment (LIFE) Study. Harvard University researchers followed the couples for one year, as participants documented their seafood intake and sexual activity on a daily basis.
The research team found that 92 percent of couples who ate seafood more than twice a week were pregnant at the end of one year, compared to 79 percent of couples who ate less seafood.
“Our results stress the importance of not only female, but also male diet on time to pregnancy and suggests that both partners should be incorporating more seafood into their diets for the maximum fertility benefit,” said Gaskins.
Trump admin to lift restrictions on hunting bears and wolves
The Trump administration is moving to lift restrictions on sport hunting and trapping in national reserves. The proposed changes would make it legal to hunt black bears with dogs, shoot swimming caribou from boats, and kill wolves and pups in their dens.
Furthermore, hunters on some public lands in Alaska would be permitted to lure brown bears with food and use spotlights to shoot hibernating black bears and their cubs.
In 2015, these and other hunting methods were outlawed under President Obama. If passed, the new legislation will remove the hunting restrictions on 20 million acres of federally preserved land.
On Monday, the National Park Service (NPS) announced its intentions to move forward with the proposal in an effort to establish better consistency with state regulations.
Maria Gladziszewski is Alaska’s deputy director of the Division of Wildlife Conservation. She told the Associated Press that the Alaska Department of Fish and Game was “pleased to see the National Park Service working to better align federal regulations with State of Alaska hunting and trapping regulations.”
Gladziszewski said that the proposal is “progress in that direction, and we appreciate those efforts. Alaskans benefit when state and federal regulations are consistent.” She explained that the state can currently only conduct predator control in national reserves with federal authorization.
Collette Adkins is a biologist at the Center for Biological Diversity. “Cruel and harmful hunting methods like killing bear cubs and their mothers near dens have no place on our national preserves,” said Adkins.
The National Parks Conservation Association (NPCA) is also opposed to the amendment, arguing that national preserves should be managed according to national park regulations.
Jim Adams is the regional director of NPCA Alaska.
“Hunting is allowed on national preserves. It’s appropriate on national preserves,” Adams told KTUU-TV. “But turning them into glorified game farms by reducing bear and wolf populations is not appropriate and it’s not right.”
The public has 60 days to comment on the proposal, which can be done by using this link to regulations.gov.
Transgender brains match their desired gender at a young age
A new study has found that the brain activity of young transgender people matches the gender they identify with, as opposed to the sex that they were born with.
Researchers from the Netherlands and Belgium set out to better understand the brain activity of young transgender people and to see if MRI scans could shed insight into how best to treat gender dysphoria at an early age.
Transgenderism is defined as identifying with a gender different from one’s assigned biological sex. Someone who is cisgender, conversely, identifies with the gender they were born with.
Gender dysphoria (GD) can result due to the stress of being faced with a gender or identity that doesn’t match what someone may internally identify with and can lead to serious psychological issues.
“It is important to study the origin of sex differences in the brain, not only for making clinical decisions for people suffering from disorders of sex development or from gender dysphoria, but also because there are important sex differences in the incidence of a wide variety of neurological diseases such as autism, depression, schizophrenia and neurodegenerative diseases such as Alzheimer’s disease,” said Julie Baker, the study’s lead author from the University of Liège in Belgium.
The researchers analyzed MRI scans of around 160 young transgender people and the study participants included both adolescent boys and girls with gender dysphoria.
The study participants were exposed to a pheromone that produces gender-specific activity in the brain and the MRI scans showed how the brain responded to the pheromone.
Brain activity of the participants matched the activity and brain patterns of cisgendered individuals from the participants’ desired genders.
In other words, whatever gender the study participants identified with, regardless of their biological sex, their brain activity matched.
A misconception of the LGBT community is the idea that these preferences are a “lifestyle choice,” or that choosing to identify as a different gender is psychological. But more and more science has shown that this is not the case.
“It used to be held long ago that all of this was psychological, and over the years the pendulum of ‘Is it nature or nurture?’ has swung rather more toward the nature side of it, with increasing peculiar pieces of biological evidence suggesting there may be something innate in the pre-uterine environment,” James Barrett told Newsweek, who reported on the study.
Barrett is the president of the British Association of Gender Identity Specialists, who peer reviewed the new study
The results show that MRI imaging could help with early detection of transgenderism and GD among young people which can pave the way for better treatments and an overall improved quality of life and transition for both individuals and their families.
Some treatments that have been met with success include delaying puberty with hormones and psychotherapy.
“The earlier it [being transgender] is detected, the better the outcome of the treatment,” said Baker in an interview with Newsweek. “For instance in the Netherlands, youngsters are being treated with puberty inhibitors at 12 years of age to prevent the development of secondary sex characteristics which are difficult or even impossible to reverse (like the lowering of the voice in boys) and then at 16 years of age, they can start with cross-sex hormones. It has been shown that these youngsters are doing relatively well and are well accepted by their peers.”
It only takes an hour for a hot car to become deadly
Researchers at Arizona State University (ASU) have investigated how quickly various types of cars warm up when exposed to different levels of shade and sunlight on hot days. They found that the dashboard of a car can reach 160 degrees in an hour, which is about the same amount of time that it would take for a child trapped inside to have a heatstroke.
So far this year, six children left in hot cars in the United States have died, and this number is expected to rise. Every year in the United States, an average of 37 children die from hyperthermia in hot cars. Over half of these deaths are caused when a parent or caretaker forgets that their child has been left in the car.
Nancy Selover is a climatologist and research professor in ASU’s School of Geographical Sciences and Urban Planning.
“Our study not only quantifies temperature differences inside vehicles parked in the shade and the sun, but it also makes clear that even parking a vehicle in the shade can be lethal to a small child,” said Professor Selover.
The researchers used identical pairs of mid-size sedans, economy cars, and minivans for the study. While outdoor temperatures were in the 100s, the team moved the cars from sunlight to shade for different time intervals throughout the day, measuring surface and interior air temperatures.
“These tests replicated what might happen during a shopping trip,” said Professor Selover. “We wanted to know what the interior of each vehicle would be like after one hour, about the amount of time it would take to get groceries. I knew the temperatures would be hot, but I was surprised by the surface temperatures.”
Among vehicles parked in the sun, the average cabin temperature hit 116 degrees in just one hour. Dashboards reached an average of 157 degrees, steering wheels reached 127 degrees, and seats heated up to 123 degrees in the same time frame.
For vehicles parked in the shade, interior temperatures averaged 100 degrees after an hour. Dashboards hit 118 degrees, steering wheels reached 107 degrees, and seats warmed up to 105 degrees. In addition, the economy car heated up faster than the mid-size sedan and minivan.
“We’ve all gone back to our cars on hot days and have been barely able to touch the steering wheel,” said Professor Selover. “But, imagine what that would be like to a child trapped in a car seat. And once you introduce a person into these hot cars, they are exhaling humidity into the air. When there is more humidity in the air, a person can’t cool down by sweating because sweat won’t evaporate as quickly.”
It is not possible to predict exactly when a child’s core body temperature will rise above 104 degrees, which is heatstroke level, because individual factors such as clothing, health, and weight affect when heat becomes a fatal risk.
The researchers used data to model a hypothetical 2-year old boy’s body temperature. The team found that a child trapped in a hot car could reach a deadly core body temperature in about an hour if a car is parked in the sun, and just under two hours if the car is parked in the shade.
“We hope these findings can be leveraged for the awareness and prevention of pediatric vehicular heatstroke and the creation and adoption of in-vehicle technology to alert parents of forgotten children,” said study lead author Jennifer Vanos.
The research is published in the journal Temperature.
Reduce congestion by calculating ideal number of taxis for a city
Self-driving cars will soon change the way that people commute in the city. Private car ownership will be largely replaced by shared mobility, which is transportation services that are shared among users on-demand.
A shift to shared mobility will reduce both traffic congestion and air pollution in urban areas. The issue, however, is determining how many vehicles are needed within each city to meet the on-demand needs of commuters. For years, researchers have struggled to develop a mathematical model capable of effectively calculating these numbers.
Experts at the Massachusetts Institute of Technology have just announced the discovery of a computationally efficient solution, which they have named the “minimum fleet problem,” that can be applied to even the largest cities.
“We started looking into this problem motivated by the increasing trends toward shared mobility, which will likely become even stronger with the transition to autonomous vehicles,” said study co-author Professor Carlo Ratti.
“If demand for mobility is served by fleets of shared vehicles, a fundamental question is: How many vehicles do we need to serve the mobility needs of, say, a city such as New York?”
Study lead author Paolo Santi explained that while previous solutions have been proposed for fleet management, they have been constrained in size, meaning they can only be computed for fleets with just a few tens of vehicles.
“If we were to consider replacing the current taxi system in New York with an optimized fleet of vehicles, we would have to find the best way of serving the around 500,000 trips made in a day, which are currently served by about 13,500 taxis,” said Santi.
The researchers used a network-based model which they named the “vehicle sharing network” in their approach to the problem.
The algorithm represented the shareability of the taxi fleet as a graph consisting of nodes and edges. The nodes were used to represent trips, and the edges were used to represent the fact that two specific trips can be served by a single vehicle.
The experts found that the graph enabled the algorithm to find the best solution for fleet sharing. They tested the solution on a data set of 150 million taxi trips taken in New York over the course of one year. They used the Manhattan road network and GPS-based estimations derived from taxi trip datasets to compute travel times.
The researchers found that real-time implementation of the method could reduce the current fleet size by 30 percent, while still providing optimal service. According to Ratti, the solution could become even more relevant in the years ahead, as fleets of networked, self-driving cars become commonplace.
“If we look at Manhattan as a whole, we could theoretically satisfy its mobility demand with approximately 140,000 vehicles – around half of today’s number,” said Ratti. “This shows that tomorrow’s urban problems regarding mobility can be tackled not necessarily with more physical infrastructure but with more intelligence, or in other words: with more silicon and less asphalt.”
The study is published in the journal Nature.