Abstract: The estimation method deseribed in this paper provides a means to calculate turning flows for intersections where inflows and outflows are known.The basic idea of the estimation method is that the turning flows should be compatible with inflows and outflows.Since the constraints on the inflow-outflows don't determine the turningflows uniquely the most probable solution which is defined as the solution with maximizing entropy is selected from the set of feasible solution.The estimation of turning flows can be transformed into a nonlinear programming problem by maximizing entropy contained in the solution.