Delays at oversaturated unsignalized intersections based on reserve capacities

There is a practical need for estimating average delays at intersections, especially during peak periods, even if a temporary overload must be managed by the intersection. Suitable computation formulas must always be based on approximations. The formulas available are based on the degree of saturation x, where x > 1 describes the oversaturated situation. The application of x has proven to be successful in the context of signalized intersections. For unsignalized intersections, the reserve capacity R is a more elegant parameter. Here R < 0 describes the oversaturated situation. The coordinate transformation technique applied for R to derive average delays during peak periods is explained. The complexity of many influencing parameters and the algebraic solutions make it impossible to solve the complete problem analytically. However, for two levels of approximation, a set of formulas is derived to estimate the average delay during a peak hour for the vehicles on the minor street of an unsignalized intersection. These formulas can be used for practical application.