Networking Reference
In-Depth Information
The technique used to generate mobility traces of the
region of Zurich, Switzerland, in [BAU 08], is instead slightly
different. Apart from the microscopic simulation environment
adopted, that is this time Generic Mobility Simulation
Framework (GMSF), and the road topology information,
retrieved from the Swiss Geographic Information System
(GIS), the macroscopic traffic flows are injected assuming
that larger roads attract more traffic. The features of the
resulting mobility are reported in Figure 6.7, for one of the
scenarios in [BAU 08], namely that representing the city
center (the others refer instead to suburban and rural areas).
From the traffic snapshot, in Figure 6.7(a), we can observe
that, in the small region compassed by the simulation (less
than 10 km 2 ), the traffic tends to be consistently slow over
the whole street layout. Such a uniformity is also present in
time, as the number of vehicles in the region and the average
speed are constant over the 20 min of duration of the trace.
Overall, the Zurich city center trace exhibits speeds
exceedingly low with respect to the traffic volume considered.
More importantly, the mobility description appears
significantly limited in terms of size and temporal duration.
5
50
vehicles
speed
4
40
3
30
2
20
500 m
1
10
0
25 0
0
5
10
15
20
Time (min)
a) Traffic snapshot
b) Traffic volume and speed
Figure 6.7. Zurich scenario: city center
In fact, a common weakness of traces built on simplistic
macroscopic traffic descriptions is that they show limited
extension, in both space and time. As a matter of fact, they