Average delay is an important criterion of evaluating traffic signals. Traf
fic signals, stream merges, and stream splits influence vehicular delay in
signalized networks through influencing random fluctuation of traffic. This
paper proposes a method of estimating the random component of queues and d
elays at signalized intersections inside a network of urban streets. Equati
ons describing the effect of signals and traffic merging and splitting are
derived, as well as a comprehensive equation combining the considered effec
ts. Fixed speeds and capacities are assumed. The derived comprehensive equa
tion is used to discuss certain cases of signalized streets. The equation i
s evaluated using the Monte Carlo technique. The proposed method can be inc
orporated into existing procedures for evaluating and optimizing traffic si
gnals.