Based on field measurements, a simulation model was developed permitting the evaluation of traffic flow on upgrades. Particular emphasis was placed on testing the model. In the present practice the transformation of heavy vehicles into passenger car units for the determination of the capacity on directional roadways is carried out under the assumption that there is a proportionality between the increasing disturbances and the number of trucks. Simulation results showed that this relationship does not exits. Using average passenger-car speeds determined from the simulation model, and by employing regression analyses, limits for various lengths and gradients of uphill sections were established beyond which an additional third lane is either required or desirable.
Abstract