The study created a method for evaluating urban traffic flow sustainability, considering variations in traffic density and vehicle speed during “rush hours.” This new approach complements existing performance criteria and improves the accuracy of predicting traffic jams. The proposed changes in traffic flow density and vehicles’ speed within the flow vary over time. In addition to the current time, the functions contain variable characteristics in the form of vibration amplitude and vibration period. This allows for adapting the forecasting model to the real road network, considering the network jams period and road infrastructure. The idea involves modeling and predicting urban traffic flow sustainability to anticipate traffic congestion. The key components of the concept are justified, outlining the stages at which this assessment is conducted while considering the dynamic changes in influential factors. The proposed concept differs from existing ones in that it considers variations in traffic flow parameters, such as density and vehicle speed over time. These changes are typical in urban road networks during peak hours.