Metod för beräkning av fördröjningar på vägavsnitt utan omkörningsmöjlighet. [Method for calculating delay on one lane road sections without overtaking possibilities].

This VTI report presents a method for calculating expected queue length and travel time delay on one lane road sections without overtaking possibilities. The method was developed 2001 and presented in a working paper. The background for the model development was that the Swedish Road Administration (now the Swedish Transport Administration) planned to build so called 1+1 roads, i.e. roads with longer sections without overtaking possibilities. The method developed has later on also shown to be valuable for level of service calculations of 2+1 roads with varying share of two lane sections and for developing speed-flow relationships for the Administration’s ”Effect calculations for road facilities”. The method uses section length, traffic flow, average speed and standard deviation as input. The method is divided with respect to calculation of effects due to single slow-running vehicles and effects at “normal” speed distribution. Since no data were available when the model was developed, the model results were instead compared to traffic simulations with the microscopic traffic simulation model AIMSUN. The results show a good correlation but the analytical model gives in general approximately 1.2 per cent lower travel time delay. The differences can probably partly be explained by the stochastic parts of the simulation model. One should also remember that neither the analytical model nor the simulation model has been calibrated and validated with real data for this type of roads. Thus, the differences between the models do not necessary imply that the analytical model is the one deviating from reality. (Author/publisher) This report may be accessed by Internet users at http://www.vti.se/en/publications/method-for-calculating-delay-on-one-l…