The signal control of the congestion length in a two-way urban
road network means that the three signal control parameters are
controlled systematically and sequentially so as to minimize the
performance criterion of the urban road network described by Eq. 4,
under such a constraint that the sum of the green time, yellow time
and offset at each signal intersection in a closed link equal to n
times of the common cycle length. We call this control algorithm as
the network control algorithm