  Multiband models with hot spots are of current interest partly because of
their relevance for the iron-based superconductors. In these materials, the
momentum-dependent scattering off spin fluctuations and the ellipticity of the
electron Fermi pockets are responsible for anisotropy of the lifetimes of
excitations around the Fermi surface. The deep minima of the lifetimes---the
so-called hot spots---have been assumed to contribute little to the transport
as is indeed predicted by a simple relaxation-time approach. Calculating
forward-scattering corrections to this approximation, we find that the
effective transport times are much more isotropic than the lifetimes and that,
therefore, the hot spots contribute to the transport even in the case of strong
spin-fluctuation scattering. We discuss this effect on the basis of an
analytical solution of the Boltzmann equation and calculate numerically the
temperature and doping dependence of the resistivity and the Hall, Seebeck, and
Nernst coefficients.
