We recently presented a new phenomenological approach (EPOS)
for proton-proton or proton-nucleus collisions at ultrarelativistic
energies.
We discuss the basic ingredients of the model (most important: elastic
and inelastic parton ladder splitting) and compare with other models.
We finally investigate in detail transverse momentum spectra
of charged particles and also of identified hadrons
in proton-proton and deuteron-gold collisions at RHIC,
in order to understand the wealth of experimental data.