LE13030
- As a Mayor of a growing city with traffic issues: would you choose
Manhattan-like road patterns or more “disordered” old European styles?
As a cellular biologist: do you understand how active transport on
biofilament networks organizes inside a cell?
The question of how the structure of a network affects its transport
properties dates back to 19th century Kirchhoff's work on the
conductance of resistor networks. Kirchhoff's well-known linear laws are
nowadays the basis of any electric circuit “current-voltage” analysis.
Network transport characteristics, however, are trickier if the conveyed
species reciprocally interact in narrow channels or on filamentous
structures: non-linear collective phenomena such as queues or jams can
appear.
A paradigmatic model to study traffic phenomena is the Totally
Asymmetric Simple Exclusion Process: particles move stochastically along
one-way lanes and cannot occupy the same position in space.
Via this model, we show that connectivity is very important for traffic
issues on networks. "Regular" connectivities, with junctions having an
equal number of incoming and outgoing segments, produce fluctuating jams
at each junction. Differently and surprisingly, in “irregular”
connectivities traffic jams as such disappear altogether, leaving high
or low dense traffic lanes with small transport fluctuations.
In urban traffic, these results would suggest that rationally designed
Manhattan-like road layouts could lead to traffic jams everywhere,
whereas the anarchy of historically grown cities could help avoiding
this problem. Speculations on the complex layout of cytoskeletal
transport in living cells are tempting…
