CHAPTER1. INTRODUCTION
Regions are highly autonomous. When simulation of a new re-
gion is deployed, it will automatically connect and synchronize with
the adjoining regions already running, accepting incoming vehicles,
and sending outgoing vehicles.... This approach allows flexible sim-
ulation of large traffic networks. Regions can be distributed to the
computers on the network, and depending on the level of interest,
each region can be simulated in detail in micro level, abstractly in
macro level, or it may not even be simulated, by relying on probabil-
ity distributions to model the traffic coming out of that region. Thus
this approach helps integrate partitions of large traffic network simu-
lations that use very different simulation techniques.
Intersection agents are responsible for controlling the flow of ve-
hicle agents from one segment to the next. They operate the traf-
fic lights. Intersection agents at the boundary of a region can act as
sources or sinks when the adjoining region is not being simulated.
In such a situation, the intersection will generate the incoming traffic
using a probability distribution.
A vehicle agent contains the physical attributes of the vehicle such
as length, acceleration, type, as well as the driver’s characteristics,
such as aggressiveness and route. It also includes the car-following
and lane-changing behavior. In implementing those behaviors, the
vehicle agent needs to continuously interact with the vehicles around
it. In order to provide fast communication among interacting vehicle
agents, vehicle agents are implemented as aglets, and hosted on the
road segment agent that they travel on. An aglet has the same concep-
tual attributes and the behavior as an agent, except that fellow aglets
hosted on the same agent can have very fast, shared-memory commu-
nication. The road segment agent monitors the position and the lane
of the vehicles on it, and interfaces with the two intersection agents at
either end. It also hosts the sensor and advisory-sign aglets.