  We assume that the early evolution of matter produced in relativistic
heavy-ion collisions is described by the transverse hydrodynamics. In this
approach only transverse degrees of freedom are thermalized, while the
longitudinal motion is described by free streaming. When the energy density of
the system drops to a certain value, the system becomes isotropic (locally, in
the momentum space) and freezes out. The sudden isotropization transition is
described with the help of the Landau matching conditions, and the freeze-out
is modeled with THERMINATOR. Within this scenario one is able to reproduce in
the quite satisfactory way the transverse-momentum spectra, the elliptic flow
coefficient v2, and the HBT radii of pions and kaons studied at RHIC (Au+Au
collisions at the top beam energy). The obtained results indicate that the
system produced at RHIC does not have to be fully thermalized in the early
stage. On the other hand, the final three-dimensional thermalization is
necessary to reproduce the HBT radius Rlong.
