This study proposes an approach to determine transport delays at unsignalized intersections, according to the theory of stationary Poisson flow and considering the priority of vehicle traffic in competing directions. The accuracy of the proposed approach was estimated by comparing the average values of delays of vehicles performing a left turn from a minor road and their actual values obtained as a result of processing data from field studies. The results of the accuracy evaluation at unsignalized intersections of non-equivalent roads indicate the obtained results' reliability, because the calculation error does not exceed 10 %, as well as the possibility of using the developed approach in the process of transport planning and unsignalized intersections modelling.