Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Bad driving holds the secret to traffic forecasts

01.07.2004


A traffic simulation system is helping drivers by predicting jams on Germany’s autobahn network up to an hour before they happen. The secret of its success is to take into account the way real drivers - and their cars - behave. When engineers model the way road traffic flows they break the traffic down into three categories: freely flowing, jammed, and an intermediate state called synchronised flow in which dense traffic moves in unison, like marchers moving in step.

But this synchronised flow is unstable. One car pulling into another lane and forcing the driver behind to brake hard is enough to start traffic bunching up. This can quickly develop into a jam that propagates backwards through the traffic like a wave. Failure to predict this "pinch effect" has stymied past attempts to model traffic flow.

Now Michael Schreckenberg and colleagues at the University of Duisburg-Essen in Germany have developed a computer model that successfully reproduces the pinch effect. "It is the first model to reproduce all known traffic states," says team member Robert Barlovic. The team’s trick is to be realistic about driver behaviour. "Real drivers tend to hinder each other when doing things like changing lanes. All this has to be taken into account," says Schreckenberg. And where previous models have simplified the way cars move- by assuming they can stop immediately without slowing down first, for example- the new model is more sophisticated.



Schreckenberg’s computer model divides the road into a regular grid, with one line of cells representing each lane on a highway. Cells in the grid are marked as either containing a vehicle or empty. The number of empty cells between the virtual vehicles depends on the way the drivers are behaving. Accuracy not seen before has been achieved by modelling two behaviours, says Schreckenberg. These are dubbed "aggressive" behaviour, in which drivers either get too close to the car in front and have to brake, or in which they change lanes too quickly, forcing others to brake. The second behaviour is "defensive", in which they drive at a generally safe distance.

As the model runs, it moves vehicles according to rules that embody realistic rates of acceleration and deceleration. No infinite decelerations are allowed, for instance. The result is a software model that combines realistic driver behaviour with realistic physics.

The model is already being used to forecast traffic on the autobahn network around the city of Cologne, based on traffic data gathered in real time from sensors buried in the road. Its forecasts, which predict conditions up to an hour ahead, are displayed on the web at www.autobahn.nrw.de. More than 90 per cent of time, it correctly predicts traffic density.

But the website has already become a victim of its own success, admits Schreckenberg. Some of the 300,000 people a day who are visiting the site are replanning their journeys on the basis of its forecasts, and this is beginning to make the forecasts themselves less accurate. And soon it could get even worse when the website becomes available on 3G cellphones, he says.

So the researchers are now trying to adjust the way the traffic information is provided to drivers to take this destructive effect into account. One idea, says Schreckenberg, might actually be to provide less complete traffic information to encourage drivers to adopt more varied strategies for evading congestion, so they do not all flock to the same exits.

Justin Mullins | alfa
Further information:
http://www.uni-duisburg-essen.de

More articles from Transportation and Logistics:

nachricht New players, standardization and digitalization for more rail freight transport
16.07.2018 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)

nachricht A helping (Sens)Hand
11.04.2018 | Fraunhofer-Institut für Arbeitswirtschaft und Organisation IAO

All articles from Transportation and Logistics >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

Purdue cancer identity technology makes it easier to find a tumor's 'address'

16.11.2018 | Health and Medicine

Good preparation is half the digestion

16.11.2018 | Life Sciences

Microscope measures muscle weakness

16.11.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>