  The assumption of local equilibrium in relativistic heavy ion collisions at
energies from 10.7 AGeV (AGS) up to 160 AGeV (SPS) is checked in the
microscopic transport model. Dynamical calculations performed for a central
cell in the reaction are compared to the predictions of the thermal statistical
model. We find that kinetic, thermal and chemical equilibration of the
expanding hadronic matter are nearly approached late in central collisions at
AGS energy for $t \geq 10$ fm/$c$ in a central cell. At these times the
equation of state may be approximated by a simple dependence $P \cong
(0.12-0.15) \epsilon$. Increasing deviations of the yields and the energy
spectra of hadrons from statistical model values are observed for increasing
energy, 40 AGeV and 160 AGeV. These violations of local equilibrium indicate
that a fully equilibrated state is not reached, not even in the central cell of
heavy ion collisions at energies above 10 AGeV. The origin of these findings is
traced to the multiparticle decays of strings and many-body decays of
resonances.
