Research Article

Metamodel-Based Optimization Method for Traffic Network Signal Design under Stochastic Demand

Table 4

Computation time and optimal solution with initial points (0.8, 0.2, 0.8, and 0.2).

MethodComputation time (s)Improvement factor (iteration)Total travel cost (veh/h)Increase in total travel cost (%)

The original problem under stochastic demand9.64822008.76 
Physical metamodel0.898510.73 (5)2052.922.20
Combined metamodel method with model bias0.787812.25 (5)2013.180.22
Gradient-based metamodel1.99164.84 (11)2010.570.09