the shortest way to the exit. Since for $\mu =0$ there is no internal pressure between the particles the evacuation time is minimal. However, for $\mu\longrightarrow 1$ the number of unsolved conflicts increases with $k_S$ due to the strong jamming at the exit. This results in stucking and clogging phenomena and highly increased evacuation times. For very high $\mu$ values ($\mu=0.9$ in fig. \[plot\_4\]) one finds a [*minimal*]{} evacuation time for an intermediate coupling ($k_S\approx 1$). This means that a larger $k_S$, which implies a larger average velocity of freely moving pedestrians, leads to larger evacuation times. This collective phenomenon is very similar to the faster-is-slower effect [@HePED; @panic]. Note that a similar minimum is characteristic for the cooperative regime. However, there local minima have been observed as a function of the coupling $k_D$ to the dynamic floor instead of $k_S$ [@aki0].

Time evolution of an evacuation {#timevolv}
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In the following we look at the time evolution of an evacuation, i.e.  the number of people who left the room at a certain time stage. Figs. \[plot\_5\] and \[plot\_5b\] show the time dependence of the number of evacuated persons for all three regimes and different $\mu$ values for a high 