I. Introduction and Background
THE urban road networks are growing ever increasingly busy and traffic-jams have become a day-to-day practice for most commuters, while coping with the increasing and dynamic changing of traffic conditions in large cities remains largely an unsolved problem. In Copenhagen alone, traffic values have increased with over 50% since the 1980s; furthermore, in 2012 people were spending over 100,000 hours in queues, corresponding to an economic loss of more than 750 million Euros [1]. It is clear these issues require addressing quickly if the road network is to avoid collapse in the near future. Improving the efficiency over road networks can be done by re-designing the network. However, construction of new roads or expanding existing ones is hampered by restrictive European legislation, that enforces new rules concerning air and noise pollution [1]. A second, preferred approach is to optimize traffic flow.