Visualizations with the
The videos show a microsimulation of the most frequent cause
of traffic jams: An
on-ramp serving as as a bottleneck. Particularly, you can see the
TU Dresden 3d traffic simulator
- There is free traffic after the bottleneck, although
there the traffic flow is higher since the road must
accommodate the onramp vehicles as well.
example video (3.3 MB)
starts with the driver's perspective.
You encounter a traffic jam
without obvious cause ("phantom jam"), or stop-and-go traffic,
and you might ask, why all the drivers of the front vehicles brake at
Notice that, besides the ordinary speedometer, the virtual vehicle is
equipped with a Coffeemeter
sensing the "ruggedness" of the driving style: After abrupt
acceleration, braking, or lane-changing manoeuvres, the coffee
Unlike real coffee in real cups, however,
our coffeemeter refills itself as soon as
a sufficient quantity of coffee is spilled. In addition, the
spilled coffee and the coffee stains magically clean up
themselves after some time.
|| The Coffeemeter
- After some time, the perspective in the movie switches to
helicopter perspective (6.7 MB)
(it would be nice to do this in reality!).
Now you see the on-ramp acting
as bottleneck and causing the phantom jams and stop-and-go waves.
Bird's eye perspective (2.2 MB)
focusses on the situation near the ramp. Notice
the stationary downstream front
of the congestion, and the dissolution of the jam downstream
of the ramp.
In this simulation, the merging zone
implemented in a very crude way which sometimes leads
to a rather
unrealistic lane-changing behaviour from the on-ramp
to the main road.
A selection of small movies
The same movies in higher quality
Driver and Helicopter view of Stop-and-go traffic
- We start approaching a traffic jam at daylight
- After some time, the vehicles move on: One may wonder what caused
this stop? Or was this an example of the
infamous "phantom traffic jam"?
- After some time, we stop again, then go again. It would be too
nice to get an overview of the situation!
- Therefore, we rise and assume the perspective of an helicopter.
Finally, we see the reason for this traffic situation:
Disturbances of the traffic flow caised by merging
manoeuvres of vehicles entering from an on-ramp! After
having passed the on-ramp, traffic flows freely again!
Driver's view of Stop-and-go traffic with various environmental
Night, wetness and fog
- This is the same situation as in the
above, only we remain in the driver's perspective all the time.
- We start approaching a traffic jam at daylight. On the way
through the stop-and-go waves, we encounter
a foggy situation with bad visibility down to
- Afterwards, we encounter dusk, then darkness, wetness, and sometimes bad
visibility conditions in various combinations.
Last modified: Fri Jul 3 14:55:46 CEST 2009