We study the pair-production process in the presence of two counterpropagating linearly polarized short
laser pulses. By means of a nonperturbative technique, we take into account the full coordinate dependence
of the external field going beyond the dipole and standing-wave approximations. In particular, we analyze
the momentum distribution of particles created. It is demonstrated that the spatial variations of the laser
pulses may play a crucial role. The more accurate treatment reveals a number of prominent features: the
pair-production probabilities become considerably smaller, the quantitative behavior of the momentum
spectra changes dramatically, and the pulse shape effects become much less pronounced. The results of our
study are expected to be very important for future theoretical and experimental investigations.