Zaporozhtseva O. Improvement of principles for determining multilane highway capacity

Modern estimation methods and theories of top-category road capacity are analysed. Also, capacity estimation methods for highways with 4,6 and 8 lanes are examined. The principles of determining highway capacity are defined taking into account distribution of intensity, speed and density in the traffic lanes as well as their interdependencies. For the first time capacity of lane unit length is defined as a maximum specific intensity. Equations that describe growth regularities of specific intensity, its dependencies on speed and density of the flow are defined. Based on queuing theory, the delay coefficient while changing traffic lanes is defined. General index of distributing delays on highways while changing traffic lines is formalised. Video materials showing traffic flows assisted in getting a wide range of various data on the regularities in traffic flows. Empirical equations are defined. They describe regularities of changes in intensity affected by density in the first, second and third lanes in one direction within free, saturated and traffic jam states. Correlations between intensity and speed as well as regularities of speed influence on intensity are established. Such regularities have not been previously studied. It has been established that capacity grows starting from the first lane (far right) and further according to the increase in traffic speed on separate lanes. The correspondence between the delay coefficient, indicating a decrease in capacity lanes under the influence of car transition from one lane to another, and the lane field observation coefficient has been established. Based on the study, some recommendations for estimating the lane capacity value on multilane highways are developed. When designing the highway, the daily intensity of 40,000 vehicles per day was taken into account. Yet, the study shows that the highway's throughput capacity could be increased up to 57,600 vehicles per day, which is 1.44 times higher than initially planned. The economic efficiency of building expenses per vehicle using the highway would be be 984 UAH per day. Thus, in total, the highway throughput economic efficiency per day would make up 56.67 million UAH per kilometer.