Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Bad driving holds the secret to traffic forecasts


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 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:

More articles from Transportation and Logistics:

nachricht Research initiative presents new traffic technologies for cities
07.10.2015 | Fraunhofer-Institut für Arbeitswirtschaft und Organisation IAO

nachricht Green Light for Vehicle-to-Infrastructure Communications
24.09.2015 | Siemens AG

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: Kick-off for a new era of precision astronomy

The MICADO camera, a first light instrument for the European Extremely Large Telescope (E-ELT), has entered a new phase in the project: by agreeing to a Memorandum of Understanding, the partners in Germany, France, the Netherlands, Austria, and Italy, have all confirmed their participation. Following this milestone, the project's transition into its preliminary design phase was approved at a kick-off meeting held in Vienna. Two weeks earlier, on September 18, the consortium and the European Southern Observatory (ESO), which is building the telescope, have signed the corresponding collaboration agreement.

As the first dedicated camera for the E-ELT, MICADO will equip the giant telescope with a capability for diffraction-limited imaging at near-infrared...

Im Focus: Locusts at the wheel: University of Graz investigates collision detector inspired by insect eyes

Self-driving cars will be on our streets in the foreseeable future. In Graz, research is currently dedicated to an innovative driver assistance system that takes over control if there is a danger of collision. It was nature that inspired Dr Manfred Hartbauer from the Institute of Zoology at the University of Graz: in dangerous traffic situations, migratory locusts react around ten times faster than humans. Working together with an interdisciplinary team, Hartbauer is investigating an affordable collision detector that is equipped with artificial locust eyes and can recognise potential crashes in time, during both day and night.

Inspired by insects

Im Focus: Physicists shrink particle accelerator

Prototype demonstrates feasibility of building terahertz accelerators

An interdisciplinary team of researchers has built the first prototype of a miniature particle accelerator that uses terahertz radiation instead of radio...

Im Focus: Simple detection of magnetic skyrmions

New physical effect: researchers discover a change of electrical resistance in magnetic whirls

At present, tiny magnetic whirls – so called skyrmions – are discussed as promising candidates for bits in future robust and compact data storage devices. At...

Im Focus: High-speed march through a layer of graphene

In cooperation with the Center for Nano-Optics of Georgia State University in Atlanta (USA), scientists of the Laboratory for Attosecond Physics of the Max Planck Institute of Quantum Optics and the Ludwig-Maximilians-Universität have made simulations of the processes that happen when a layer of carbon atoms is irradiated with strong laser light.

Electrons hit by strong laser pulses change their location on ultrashort timescales, i.e. within a couple of attoseconds (1 as = 10 to the minus 18 sec). In...

All Focus news of the innovation-report >>>



Event News

EHFG 2015: Securing healthcare and sustainably strengthening healthcare systems

01.10.2015 | Event News

Conference in Brussels: Tracking and Tracing the Smallest Marine Life Forms

30.09.2015 | Event News

World Alzheimer`s Day – Professor Willnow: Clearer Insights into the Development of the Disease

17.09.2015 | Event News

Latest News

New microscopy technology augments surgeon's view for greater accuracy

07.10.2015 | Medical Engineering

Discovery about new battery overturns decades of false assumptions

07.10.2015 | Power and Electrical Engineering

Ancient rocks record first evidence for photosynthesis that made oxygen

07.10.2015 | Earth Sciences

More VideoLinks >>>