Abstract: (9322 Views)
This paper proposes a new hybrid method namely SA-IP including simulated annealing and interior point algorithms to
find the optimal toll prices based on level of service (LOS) in order to maximize the mobility in urban network. By considering
six fuzzy LOS for flows, the tolls of congested links can be derived by a bi-level fuzzy programming problem. The objective
function of the upper level problem is to minimize the difference between current LOS and desired LOS of links. In this level, to
find optimal toll, a simulated annealing algorithm is used. The lower level problem is a fuzzy flow estimator model with fuzzy
link costs. Applying a famous defuzzification function, a real-valued multi-commodity flow problem can be obtained. Then a
polynomial time interior point algorithm is proposed to find the optimal solution regarding to the estimated flows. In pricing
process, by imposing cost on some links with LOS F or E, users incline to use other links with better LOS and less cost. During
the iteration of SA algorithm, the LOS of a lot of links gradually closes to their desired values and so the algorithm decreases
the number of links with LOS worse than desirable LOS. Sioux Falls network is considered to illustrate the performance of SA-IP method on congestion pricing based on different LOS. In this pilot, after toll pricing, the number of links with LOS D, E and
F are reduced and LOS of a great number of links becomes C. Also the value of objective function improves 65.97% after toll
pricing process. It is shown optimal toll for considerable network is 5 dollar and by imposing higher toll, objective function
will be worse.