M.Sc Thesis
M.Sc Student Iscovitch Orly A Model to Determine the Optimal Noise Level in an Urban Road System Department of Civil and Environmental Engineering Professor Shlomo Bekhor

Abstract

The purpose of this research is to develop a model to determine the optimal noise level in an urban road network by changing the demands in the network. The combination of the traffic model and the noise calculation model makes this optimal situation possible.

# System-wide traffic predictions are derived from traffic assignmentmodel (TA model) that distributes the traffic demand over the road system. The demand is represented by an origin-destination (OD) matrix and is assigned to the road segments that make up the road system.

The mathematical formulation of the combined problem is derived from the equilibrium formulation of TA with flexible demand. The difference is that the demand function in the present case depends on the noise level and has a degree of freedom related to the demand between each OD pair in order to reach an optimal noise situation.

This research focuses on the development of an algorithm to solve the combined problem.

The algorithm is composed of three main phases. The first phase runs the TA model with an initial demand and the traffic volumes and travel times are obtained for each element of the system. The second phase calculates the initial noise levels and compares to a pre-determined noise criterion. If the criterion is exceeded in certain sections, the equivalent traffic level (in terms of noise production) is calculated for the corresponding section. The third phase corrects the travel demand for given link level constraints. The process includes a mechanism that ensures that the total demand is kept constant.

# An auxiliary algorithm was developed in order to find the maximum traffic volume on each of the road network elements without exceeding the noise criterion for each of the designated receivers. The end result of the process is a modified OD matrix which can be used for neighborhood planning. The thesis shows an implementation of the algorithm for a real case.

From the environmental point of view the possibility of planning the residential areas according to the expected noise from the neighborhood roads was demonstrated. It should be noted that noise is not the only environmental aspect under consideration during the planning process. A question left for further research is whether a network that was planned to fulfill acoustic criterion gives adequate solution to other environmental problems.