TAU NEWS – Transportation
TAU study finds direct link between online price competition and longer flight times
Once upon a time people planned their vacations by booking flights and hotel at local travel agencies. But with the Internet launching of hundreds of online flight vendors, travel agencies have virtually disappeared into the ether — and shorter flights have disappeared with them.
In a study scheduled for publication in The Review of Economics and Statistics, Dr. Itai Ater of Tel Aviv University's Recanati Business School and Dr. Eugene Orlov of Compass Lexecon examine how the Internet has affected performance and product quality in the airline industry, especially flight times. They say that the shift to online distribution channels has changed the way airlines compete for customers. Instead of competing for space at the top of travel agents' computer screens by scheduling the shortest flights, airlines have adapted to an environment in which price is playing the dominant role in selling tickets.
Time vs. money
Using flight data from 1997 through 2007 from the U.S. Bureau of Transportation Statistics and geographical growth patterns in Internet access from the Computer Use and Ownership Supplement to the Consumer Population Survey (CPS), Dr. Ater found a definitive relationship between Internet access and scheduled flight times.
His findings suggest that increased Internet commerce in the travel industry has adversely affected airline performance and dampened incentives to provide a higher-quality product, defined as shorter flight time. In addition to longer scheduled flights, the researchers found that flight delays increased as passengers used the Internet to make their reservations directly with airlines.
The study focuses on a period in which Internet access grew rapidly, from an average penetration level of 19.4 percent in U.S. metropolitan areas to 1997 to an average penetration level of 76.3 percent in American cities in 2007. The change is also reflected in the share of airline tickets sold online, from 0.5 percent in 1997 to more than 50 percent in 2007.
"While I was studying at Stanford from 2003 to 2008, I was interested in understanding why the length of 'red eye' flights between San Francisco and New York had increased from five hours and twenty minutes to five hours and forty minutes," said Dr. Ater. "It became clear, after examining flight data, that planes were flying at higher altitudes to cut fuel costs — there is less friction at higher altitudes — and thus required more time to land. But the question remained: Why? Why were airlines cutting costs at the expense of time?"
Using the scheduled duration of flight time (the time between a scheduled departure and a scheduled arrival) as his main measure for performance, Dr. Ater found that the shift in airfare distribution channels from traditional travel agencies to online distribution channels explained a large fraction of the upward trend to longer flights.
Blame the Internet for your delay
The study also shows that the effect of Internet commerce on flight duration is pronounced for the fastest flights on a given route — flights that in the pre-Internet era appeared at the top of the screens of traditional travel agents.
"In the early 1990s, when travel agencies sold over 80 percent of airline tickets, flights typically appeared on the travel agent's screen in ascending order according to their scheduled durations," said Dr. Ater. "Given that travel agents booked over 80 percent of flights from the first screen and that the majority of the tickets were sold from the first line of search results, airlines had strong incentives to maintain short scheduled flying times. This incentive changed as the Internet became the most common channel for purchasing airline tickets, and flight duration was no longer the main criterion to sort flights."
Dr. Ater says extended flight duration is just one example of the way in which product quality has fallen since the advent of the Internet. He is continuing to research the effect of information and communication technologies on productivity and performance.
TAU researchers develop program to identify traffic "black spots"
Traffic planners and engineers worry about “black spots” — intersections that experience a high incidence of traffic accidents. But when it comes to designing safer roads, they lack effective tools to determine what turns a junction into a danger zone for cars and pedestrians alike.
Now Ph.D. student Gennady Waizman of Tel Aviv University’s Geosimulation Lab at the Department of Geography and the Human Environment and Porter School of Environmental Science has developed SAFEPED, a computer simulation that integrates robotics and statistics on driver and pedestrian behavior to determine the environmental features which lead to these black spots. Based on real-world data, SAFEPED is more true-to-life than other computer traffic models.
SAFEPED allows traffic planners and engineers to analyze and fix dangerous intersections. It also permits these engineers to test and rearrange the architecture of a planned junction and design it for optimal safety. The model has been presented at the Transportation Research Board Conference on Safety and Mobility in Jerusalem, and this July at the Geocomputation 2011 conference in London.
Countdown to collision
SAFEPED considers each car and pedestrian an autonomous “agent,” with the ability to reason and react based on its individual predictions of how surrounding agents will behave. This is a significant improvement on other computer models of traffic, which do not account for the human ability to see the world in three dimensions, predict the actions of others, and react accordingly.
“Because drivers and pedestrians behave according to the same habits and rules at any intersection they approach,” Waizman explains, “we presumed that the problem lay in the environment. With this program, we can model a real intersection in the simulator, and make modifications to the environment or traffic regulations to see how they impact the safety of the junction.”
But the researchers knew that it was not enough to place traditional robotic agents into the environment. Such non-thinking robots could not give them an accurate indication of how a changed traffic architecture could affect accident rates. Instead, Waizman’s team based their simulator on a theory of visual perception developed by the cognitive scientist James J. Gibson. When humans move through a given environment, Gibson theorized, they analyze their “optic flow” as they move, taking into account their anticipated time of collision with other objects or people.
Averting a crash before it happens
In SAFEPED, all agents move and think individually, and they determine their actions based on visibility and the movement of the other agents. Depending on what they perceive and predict, agents slow down, accelerate, or divert. The researchers can see an accident from the viewpoint of any agent to determine where visibility was impaired or an agent made a wrong decision. They can also rewind a virtual accident and determine if a change in regulations or architecture could have averted the crash.
The agents’ behavior is based on traffic statistics provided by the Israeli police force and on hours of observation by M.A. student Eilon Blank-Baron, who recorded videos of intersections, analyzed the behavior of the moving drivers and pedestrians, and integrated the resulting data into SAFEPED to make the simulator more realistic. Two synchronized cameras observed how cars and pedestrians reacted to one another.
The SAFEPED research has already led to many important findings. The probability that pedestrians will cross a busy road, for example, is based on how they estimate the velocity of an approaching car. If they believe the car will cross the intersection in less than 2.5 seconds, people will not cross. At 5.5 or 6 seconds, however, most people will cross the road. It also found that the further back a white stop line is set in an intersection, the smaller the chance that a pedestrian will be struck by a car.
Waizman’s and Blank-Baron’s research is supervised by Prof. Itzhak Benenson of TAU’s Department of Geography and Human Environment and Prof. Shraga Shoval of the Ariel University Center.
TAU develops scheduling tool to save time on public transport
What matters for commuters is not just if the train will be on time, but how long the journey will take. It's an important factor in public transportation and can make the difference in helping commuters choose mass transit over more polluting and costly transport like cars or airplanes.
Dr. Tal Raviv and his graduate student Mor Kaspi of Tel Aviv University's Department of Industrial Engineering in the Iby and Aladar Fleischman Faculty of Engineering have developed a tool that makes passenger train journeys shorter, especially when transfers are involved — a computer-based system to shave precious travel minutes off a passenger's journey.
Dr. Raviv's solution, the "Service Oriented Timetable," relies on computers and complicated algorithms to do the scheduling. "Our solution is useful for any metropolitan region where passengers are transferring from one train to another, and where train service providers need to ensure that the highest number of travellers can make it from Point A to Point B as quickly as possible," says Dr. Raviv.
Saves time and resources
In the recent economic downturn, more people are seeking to scale back their monthly transportation costs. Public transportation is a win-win — good for both the bank account and the environment. But when travel routes are complicated by transfers, it becomes a hard job to manage who can wait — and who can't — between trains.
Another factor is consumer preference. Ideally, each passenger would like a direct train to his destination, with no stops en route. But passengers with different itineraries must compete for the system's resources. Adding a stop at a certain station will improve service for passengers for whom the station is the final destination, but will cause a delay for passengers who are only passing through it. The question is how to devise a schedule which is fair for everyone. What are the decisions that will improve the overall condition of passengers in the train system?
It's not about adding more resources to the system, but more intelligently managing what's already there, Dr. Raviv explains.
More time on the train, less time on the platform
In their train timetabling system, Dr. Raviv and Kaspi study the timetables to find places in the train scheduling system that can be optimized so passengers make it to their final destination faster.
Traditionally, train planners looked for solutions based on the frequency of trains passing through certain stops. Dr. Raviv and Kaspi, however, are developing a high-tech solution for scheduling trains that considers the total travel time of passengers, including their waiting time at transfer stations.
"Let's say you commute to Manhattan from New Jersey every day. We can find a way to synchronize trains to minimize the average travel time of passengers," says Dr. Raviv. "That will make people working in New York a lot happier."
The project has already been simulated on the Israel Railway, reducing the average travel time per commuter from 60 to 48 minutes. The tool can be most useful in countries and cities, he notes, where train schedules are robust and very complicated.
The researchers won a competition of the Railway Application Section of the International Institute for Operation Research and Management Science (INFORMS) last November for their computer program that optimizes a refuelling schedule for freight trains. Dr. Raviv also works on optimizing other forms of public transport, including the bike-sharing programs found in over 400 cities around the world today.
The new environmentally-friendly concept of municipal "bike-sharing is taking over European cities like Paris, and American cities like New York are also looking into the idea. It allows a subscriber to "borrow" a bike from one of hundreds of locations in the city, use it, and return it to another location at the end of the journey. It's good for commuters and for running short errands.
TAU develops a high-tech tool to improve two-wheeled public transportation
While the idea is gaining speed and subscribers at the 400 locations around the world where it has been implemented, there have been growing pains — partly because the projects have been so successful. About seven percent of the time, users aren't able to return a bike because the station at their journey's destination is full. And sometimes stations experience bike shortages, causing frustration with the system.
To solve the problem, Dr. Tal Raviv and Prof. Michal Tzur of Tel Aviv University's Department of Industrial Engineering are developing a mathematical model to lead to a software solution. "These stations are managed imperfectly, based on what the station managers see. They use their best guesses to move bikes to different locations around the city using trucks," explains Dr. Raviv. "There is no system for more scientifically managing the availability of bikes, creating dissatisfaction among users in popular parts of the city."
Their research was presented in November 2010 at the INFORMS 2010 annual meeting in Austin, Texas.
Biking with computers
An environmentalist, Dr. Raviv wants to see more cities in America adopt the bike-sharing system. In Paris alone, there are 1,700 pick-up and drop-off stations. In New York, there soon might be double or triple that amount, making the management of bike availability an extremely daunting task.
Dr. Raviv, Prof. Tzur and their students have created a mathematical model to predict which bike stations should be refilled or emptied — and when that needs to happen. In small towns with 100 stations, mere manpower can suffice, they say. But anything more and it's really just a guessing game. A computer program will be more effective.
The researchers are the first to tackle bike-sharing system management using mathematical models and are currently developing a practical algorithmic solution. "Our research involves devising methods and algorithms to solve the routing and scheduling problems of the trucks that move fleets, as well as other operational and design challenges within this system," says Dr. Raviv.
For the built environment
The benefits of bike-sharing programs in any city are plentiful. They cut down traffic congestion and alleviate parking shortages; reduce air pollution and health effects such as asthma and bronchitis; promote fitness; and enable good complementary public transportation by allowing commuters to ride from and to train or bus stations.
Because of the low cost of implementing bike-sharing programs, cities can benefit without significant financial outlay. And in some cities today, bicycles are also the fastest form of transport during rush hour.
The city of Tel Aviv is now in the process of deploying a bike sharing system to ease transport around the city, and improve the quality of life for its residents. Tel Aviv University research is contributing to this plan, and the results will be used in a pilot site in Israel.
Thousands of people around the world have died in train wrecks caused by natural disasters. In 2004, the tsunami in Southeast Asia derailed a Sri Lankan train, killing 1,700 people. But with modern advances, these tragedies can be avoided — and a Tel Aviv Universityresearcher, working in collaboration with teams from seven countries, is leading the way.
TAU helps develop early-warning hazard system for the world's railways
Prof. Lev V. Eppelbaum of Tel Aviv University's Department of Geophysics & Planetary Sciences and his colleagues are collecting high-tech sensing data from satellites, airplanes, magnetic and soil sensors, and unmanned aircraft to devise a solution that will provide a reliable early-warning system for train operators.
It's all part of the European Project FP7 research, "Integrated System for Transport Infrastructures Surveillance and Monitoring by Electromagnetic Sensing," which includes participants from Israel, Italy, France, Sweden, Norway, Switzerland and Romania. The international team of researchers aims to connect emerging technologies so that train accidents caused by avalanches, earthquakes and even terrorists can be avoided.
A system to detect sabotage
"Sinkholes, avalanches, landslides, earthquakes, flash floods — these disasters can cause train wrecks anywhere around the world," says Prof. Eppelbaum. "We are hoping to develop a platform that can be fitted to any railway, passenger or freight carrier, to better predict natural disasters and possible terror attacks on rail lines." He says that his part of the study should be completed by next year.
"We are creating a new interpretation system — allowing us to integrate cutting-edge technologies from across Europe," he says, adding that the biggest challenge, right now, is eliminating background "noise" from the data being collected.
Climatic features and parameters such as soil types and physical geography can be very different from one region to another, which makes the work even more of a challenge. Some of Prof. Eppelbaum's recent research advances have been reported in the Zeitschrift für Geomorphologie, the Journal of Arid Environments and the Proceedings of the SAGEEP Conference (USA).
On the right Amtrak
The international team also hopes to examine the additional risk of terror attacks on trains. While all the other data collected by the research teams will be made public, this section will remain top secret.
Prof. Eppelbaum expects their methods will be adopted by the world's railway systems. As the cost of fuel for cars and planes rises, and environmentally-friendly train travel is more heavily promoted, experts predict that more Americans will be riding the rails to work and between cities. In 2008, about 30 million passengers rode on Amtrak trains, and train ridership figures have been steadily increasing.
At present, there is no monitoring system for either natural disasters or terror attacks on rail systems in America or anywhere else. Prof. Eppelbaum says he has his work cut out for him: putting together different geophysical measurements and formats of sensors, he is collecting very different kinds of data and trying to turn it into usable information.
"It's complicated math and physics," says Prof. Eppelbaum. "And yes, it includes lots of scribbling and equations on the chalkboard."
"Congestion pricing" could solve the problem of airport delays, says a TAU economist
In London, motorists pay a fee to drive into certain parts of the city during peak traffic hours, and the idea has been considered for implementation in New York as well. Now Dr. Itai Ater, an economist from Tel Aviv University's Faculty of Management, is suggesting that introducing "congestion pricing" at airports could save travellers time and airlines money.
"What I propose is a policy to reduce the amount of delays in the airline industry," says Dr. Ater. Airlines that want to use an airport's runways during the busiest times of the day, he says, should pay an additional fee. This price for premium access to the runway could reduce airport congestion — and the inevitable delays, as well as the risks, associated with crowded skies.
Dr. Ater will present his advice at the National Bureau of Economic Research conference in Boston this May. His aim is to spare airlines from future catastrophes as airports, and skies, get busier.
How the pennies (and minutes) add up
"Airport congestion is a big problem in the U.S. and around the world," says Dr. Ater, who evaluated flight records from America's busiest airports for his doctoral thesis at Stanford University. "The estimated annual costs of delays are $10 billion. When there are delays on take off or landing, a cascading effect is created, with lots of associated problems, risks and financial costs," he says.
One direct effect is that airlines spend more money on fuel, and there are indirect costs as well, mainly passengers' time. To counter delays, many airlines "pad" their schedules, adding a considerable amount of time onto the flight plan, says Dr. Ater. This padding increases the costs of staff and the busy business flyer time — something often more valuable than money.
A little extra to use the "EZ-Pass Lane"
Some airlines will prefer not to pay the charge and operate during non-congested periods, Dr. Ater says. Consequently, overall congestion would drop. Currently, airlines at most airports pay for runway use depending on the weight of the aircraft, except for a few such as Chicago O'Hare, where airports use pre-determined slots to determine charges and time of operation.
Dr. Ater warns that not all airports can benefit from his plan. "At airports where there is a monopoly or almost a monopoly by a single airline, charging a tariff during peak hours has less meaning," he says. "In these airports, like those in Atlanta, Charlotte, or Detroit, we already find fewer delays. So why intervene? Individual airlines that dominate an airport do a better job of organizing flights more intelligently and efficiently to reduce the level of delays."
Previous research on the subject found it hard to provide consistent empirical evidence for congestion pricing. By splitting airport "types" into two categories — those with a monopoly and those that host multiple airlines — Dr. Ater began to see clear patterns emerge. Congestion pricing is the right approach for airports such as Boston and LAX, he says.
No system is perfect, however. Dr. Ater suggests that the new cost might be in your convenience. For that cheaper flight, you may have to alter your plans to get to the airport a little — or a lot — earlier in the day.