Computing realistic routes for a given road network and a known demand of vehicles is one of the most important steps when preparing a road traffic simulation. The approach developed by Christian Gawron in 1998 which we use for this purpose computes a dynamic user equilibrium by iteratively performing the simulation and computing new vehicle routes. The results are valid, but the computation is very time consuming due to the need to perform both the complete simulation and rerouting of all vehicles within each iteration step. Herein, we want to discuss some approaches to reduce the needed time and memory consumption. The results show that this can be achieved without reducing the algorithm’s quality.