Vehicle to Vehicle Communications Could End Need for Traffic Lights
Claims Journal, March 2016
Imagine a scenario where sensor-laden vehicles pass through intersections by communicating with each other, rather than grinding to a halt at traffic lights. A newly published study co-authored by MIT researchers claims this kind of traffic-light-free transportation design, if it ever arrives, could allow twice as much traffic to use the roads.
The study is based on mathematical modeling. The researchers examined a scenario in which high-tech vehicles use sensors to remain at a safe distance from each other as they move through a four-way intersection. By removing the waits caused by traffic lights, these so-called Slot-based Intersections (SIs) speed up traffic flow.
An intersection is a difficult place, because you have two flows competing for the same piece of real estate,” says Carlo Ratti, a professor of the practice and director of the SENSEable City Lab in MIT’s Department of Urban Studies and Planning, and a co-author of the study. But a system with sophisticated technology and no traffic lights, he adds, “moves control from the [traffic] flow level to the vehicle level. Doing that, you can create a system that is much more efficient, because then you can make sure the vehicles get to the intersection exactly when they have a slot.”
The greater capacity of the system, notes Paolo Santi, a researcher in the SENSEable City Lab who is a member of the Italian National Research Council and another co-author of the study, does not stem from vehicles moving more quickly. Rather, it comes from creating a more consistent flow at an optimal middle speed, at which automobiles can keep moving.
“You want the car to use the intersection for the shortest possible time,” Santi says.
The paper, “Revisiting street intersections using slot-based systems,” appears in the journal PLOS One. In addition to Ratti and Santi, the paper’s co-authors are Remi Tachet and Stanislav Sobolevsky, also of the SENSEable City Lab; Luis Ignacio Reyes-Castro and Emilio Frazzoli of MIT’s Laboratory for Information and Decision Systems; and Dirk Helbing of the Swiss Federal Institute of Technology in Zurich (ETH Zurich).
The “slower is faster” approach
To see why the system could at least work in theory, consider what the researchers call the “slower is faster” effect. When passengers board an airplane, they tend to move faster if they are in smaller clusters that keep going steadily, as opposed to a scenario in which everyone crowds around the entrance, creating a giant bottleneck.
“The ‘slower is faster’ effect has been observed in many other contexts related to flow of entities, for instances pedestrians through a narrow space,” Santi explains. “If you need to slow down the vehicles because there is a lot of traffic, you slow them down early in the road, so they approach the intersection at slow speed, but then when they cross, you use the best speed.”
By “early,” Santi means that control of intelligent vehicles in the proposed system would occur not just at intersections but on the road segments leading to them. The modeling in the paper also finds that the most efficient traffic flow puts vehicles together in batches – like those smaller groups of passengers boarding a plane – and then slides them through the intersection accordingly.
“It’s like you use build the phases of a traffic light dynamically,” Santi says.
A city of slot cars
If the key to a light-free, enjoyably efficient traffic intersection is controlling the speeds of cars as they approach intersections, however, it raises further questions. In many cities, intersections with lights are often placed relatively close to each other. So how would the dynamics of traffic at one intersection propagate through a whole urban network of roads?
Ratti acknowledges the centrality of this issue and says it is currently the subject of additional study by some of the same researchers.
“If you start from the intersection, this propagates to the city level,” he says. “Part of the work we’re doing is studying that propagation.”
Still, despite the complexities that might create, Ratti thinks the intersection-first theoretical approach to urban traffic will prove beneficial: “Because the intersection is the crucial point, once you solve the intersection, it has a beneficial effect on the whole system.”
Source Massachusetts Institute of Technology
Categories
- Benefits Resources
- Bonding
- BOP
- Business Insurance
- Commercial Auto
- Commercial Property
- Company News
- Construction
- Crime Insurance
- Cyber Insurance
- Directors & Officers
- Employee Benefits
- Employment Practice Liability Insurance
- Entertainment
- General Liability
- Health Insurance
- Healthcare
- Healthcare Reform
- Homeowners Insurance
- Hospitality
- Manufacturing
- Medical Malpractice
- Mining & Energy
- Nightclubs
- Personal Auto
- Personal Insurance
- Professional
- Restaurants
- Retail & Wholesale
- Risk Management Resources
- Safety Topics
- SBA Bonds
- Security
- Seminars
- Technology
- Tourism
- Transportation
- Uncategorized
- Workers Compensation
Archives
- May 2021
- November 2020
- October 2020
- September 2020
- August 2020
- July 2020
- June 2020
- May 2020
- November 2018
- September 2018
- August 2018
- May 2018
- April 2018
- March 2018
- February 2018
- January 2018
- December 2017
- November 2017
- October 2017
- September 2017
- August 2017
- July 2017
- June 2017
- May 2017
- April 2017
- March 2017
- February 2017
- January 2017
- October 2016
- September 2016
- August 2016
- July 2016
- June 2016
- May 2016
- April 2016
- March 2016
- February 2016
- January 2016
- December 2015
- November 2015
- October 2015
- September 2015
- August 2015
- July 2015
- June 2015
- May 2015
- April 2015
- March 2015
- February 2015
- January 2015
- December 2014
- November 2014
- October 2014
- September 2014
- August 2014
- July 2014
- June 2014
- May 2014
- April 2014
- March 2014
- February 2014
- January 2014
- December 2013
- November 2013
- October 2013
- September 2013
- August 2013
- July 2013
- June 2013
- February 2013
- November 2011
- October 2011
- September 2011
- July 2011
- June 2011
- March 2011
- November 2010
- October 2010
- September 2010
- April 2010
- February 2010
- November 2009
- October 2009
- November 2008
- August 2008