.
The optimal strategy for reaching a destination is the one which minimizes the total expected cost. Note that the cost of a strategy is the sum of link travel times 
weighted by the probability of traveling on link a, and the waiting time at nodes i weighted by the probability of traveling through node i. It has been shown that for fixed link travel times , the assigning of the trips from all origins to destination r according to the optimal strategy corresponds to solving the following linear optimization problem:
subject to
Note that the variables 
represent the total waiting time (in person minutes) at node i.
The problem (3) can be solved very efficiently by means of the following label-setting type algorithm:
