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we propose a method which follows the idea to add the cars to the network
“adiabatically”, i.e., without disturbing the system. If the number of cars crossing
the checkpoint is lower than measured by the detector, cars are inserted with
regard to the measured mean velocity and mean gap, so that the system is not
disturbed, i.e., no car has to brake due to the insertion. This method is therefore
called “Tuning of the Mean Gap” [3]. If it is not possible to add the required
number of cars some vehicles are left out. Although this is not correct, it is more
important to keep the dynamics of the system untouched. It turns out that the
strategy is capable of reproducing the tra
c state quite well [3].
5 Summary and Outlook
In this paper we present a simulator of the autobahn network in North Rhine-
Westphalia. The simulator uses an advanced cellular automaton model of tra
c
flow and adjusts the tra
c state in accordance with measurements of the real
tra
c flow provided by more than 3,500 loop detectors installed locally on the
autobahn. The cellular automaton model, the abstraction of the network, the
guidance of the vehicles, and data integration strategies to periodically adjust
the tra
c flow in the simulation in accordance with the measured flow on the
autobahn were discussed.
The simulation performs in a multiple real-time on a modern personal com-
puter (Athlon
TM
XP 1600+, 512 MB DDR-RAM) and in regard to the ever
growing computational power it looks promising to combine the simulation with
historical data for tra
c forecast. A further application for the simulator is to
research the influence of new roads or road-works on the tra
c flow. Finally,
we are extending the simulator so it can be used for the research of tra
c flow
control. This is not as simple as it might seem, because any information about
the current tra
c state available to the public is likely to influence the strategy
of the drivers [22].
Acknowledgement.
The authors would like to thank the “Landesbetrieb
Straßenbau NRW” for data support and the Ministry of Economics and Small
Businesses, Technology and Transport for North Rhine-Westphalia for financial
support.
References
1.Esser J, Schreckenberg M(1997) Microscopic simulation of urban tra
c based on
cellular automata.Int.J.of Mod.Phys.C
8
, 1025-1036
2. Nagel K., Esser J., Rickert M. (2000) Large-scale tra
c simulations for transport
planning.In: Stauffer D.(Ed), Ann.Rev.of Comp.Phys.
VII
, 151-202, World
Scientific, Singapore
3. Kaumann O., Froese K., Chrobok R., Wahle J., Neubert L., Schreckenberg M.
(2000) On-line simulation of the freeway network of North Rhine-Westphalia.In:
Helbing D., Herrmann H., Schreckenberg M., Wolf D. (Eds.) (2000) Tra
c and
Granular Flow '99.Springer, Heidelberg, 351-356
