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It is developed by Parsons Brinkerhoff Farradyne Inc. and the University of
Massachusetts at Lowell jointly.
It is a distributed traffic signal control strategy.
The network is divided into sub-networks, which are considered independently
for optimization purpose.
OPAC breaks between two models: one for congested networks and the other for
uncongested networks.
- Signal timing is calculated by dynamic optimization algorithm to minimize
total intersection delay and stop.
- Algorithm uses measured and modeled demand to determine phase
distribution at each signal that are constrained by minimum and maximum green
time.
- It must provide better performance than off line methods
- It should be totally demand responsive. It means to adapt to actual
fluctuating traffic condition
- It must not be restricted to any fixed control period (e.g. 10 min)
- It is based on the pseudo dynamic programming technique, so it finds
result near to optimal but not exactly optimal.
- Its performance varies with traffic saturation condition.
Better in under saturated traffic conditions.
- It is expensive because it includes advanced technology which is
expensive and to understand and operate this type of technology person should
have very good knowledge.
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