Improving the Nomad microscopic walker model

This paper presents the results of two calibration efforts and improvements of the Nomad microscopic walker model. Each calibration consisted in comparing the outcome of 19 sets of model parameters with results from laboratory experiments. Three different flows were used in the calibrations: bidirectional, unidirectional and a narrow bottleneck. For the first two types of flow the macroscopic speed-density relation is used for comparison. For the narrow-bottleneck the capacity for the bottleneck is assessed. Additionally, quantitative measures of self-organizing lane formation for the bidirectional flow are included in the calibration. In the first calibration effort only 4 parameter sets did not present gridlocks in the bidirectional flow and their results are presented. These four sets over estimated the capacity of the bottleneck and the efficiency of the unidirectional flows. These results are discussed and it is shown that a modification in the model is necessary. A modified model is presented and submitted to a new round of calibration. One parameter set showed significant improvement for the speed-density relations and the capacity of the bottleneck. The experience gained in this calibration effort indicates that pedestrian microscopic models can be calibrated over several types of flows simultaneously. However, this research shows that care must be taken when using only macroscopic flow properties for calibration. They may not guarantee the generality of the model due to the complexity and variety of possible flows.