Greetings, all --
You may recall that this is a favorite subject of mine. This simulation may be
of interest. This is via WIRED's blog Autopia.
- Claiborne Booker -
Autopia
Master of Your Commute By Mark Durham Have you ever wished you
could tweak the CO2-spewing crawl of your commute to get it flowing like Han
Solo? Or automagically bring the truck-to-car ratio on Interstate 80 down to a
Lamborghini-friendly level? If so, Martin Treiber is your new fairy godmother.
Treiber, of the Dresden University Institute for Economics and Traffic, has
created a Java-based road traffic microsimulator that lets you toy with
traffic models to your heart's content. Choose from such scenarios as
Ringstrasse (ring road), Zufahrt (onramp), Spursperrung (lane closing), and
Deterministisches Chaos (which sounds suspiciously like drivetime on
California's Highway 280). Then nudge the slider up to, say, 4,000 vehicles per
hour, kick the Zufluss der Zufahrt (that's "ramp inflow" to you) up to 1,800
v/h, and see what ensues. Look and feel familiar? We feel your pain. Of
course, all this virtual Schadenfreude has a serious purpose: to help traffic
planners test the effects of speed limits, traffic lights, new rules, and new
infrastructure on congestion without actually putting them into place. It can
also help model the effects of adaptive cruise-control systems: "If an
increasing precentage of vehicles has such systems, does traffic become more
stable? Can the traffic flow per lane be increased?" Enquiring minds want to
know. Optimistically enough, new longitudinal and lane-change variations use
the Intelligent-Driver Model (IDM) to simulate "the longitudinal dynamics,
i.e., accelerations and braking decelerations of the drivers." Lane changes
take place, notes Trieber, if: the potential new target lane is more
attractive, i.e., the "incentive criterion" is satisfied, and the change can be
performed safely, i.e., the "safety criterion" is satisfied. If only.
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