en Transportation Transportation Research Paper Research Paper 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. Congestion pricing, Level of service, Meta-heuristic, Fuzzy travel time, Multi-commodity, Interior point method 281 291 http://ijce.iust.ac.ir/browse.php?a_code=A-10-1743-1&slc_lang=en&sid=1 S. Soudmand soodmand@aut.ac.ir 180031947532846005801 180031947532846005801 No Amirkabir University of Technology M. Ghatee ghatee@aut.ac.ir 180031947532846005802 180031947532846005802 Yes Amirkabir University of Technology S. M. Hashemi hashemi@aut.ac.ir 180031947532846005803 180031947532846005803 No Amirkabir University of Technology