Abstract In an evacuation process involving multi-exits, exit selection behavior is a significant concern for safe facility design. We improve the least effort algorithm to investigate pedestrian exit route decisions in simulated evacuations, considering crowd density around two exits. This modification extends the algorithm to support altering targets in the case of asymmetrical exits. We conduct simulations given some special distribution of pedestrians. Pedestrian exit selection behavior and herding behavior are clearly demonstrated. Moreover, the model is applied to identify the relationship between exit separation and evacuation time. The total exit flow rate against different initial crowd densities is also discussed.