TAPAAL is a tool for modelling, simulation and verification of Timed-Arc Petri nets developed at Department of Computer Science at Aalborg University in Denmark and it is available for Linux, Windows and Mac OS X platforms. Timed-Arc Petri Net (TAPN) is a time extension of the classical Petri net model (a commonly used graphical model of distributed computations introduced by Carl Adam Petri in his disseration in 1962).