  The analysis of the grey tracks produced in Deep Inelastic Scattering (DIS)
off nuclei provides important information on the space-time development of
hadronization in nuclear medium. This method is complementary to the
measurement of nuclear attenuation of leading inclusive hadrons. While the
latter is focused on the hadronization dynamics for the quite rare process of
leading hadrons production, the former covers the main bulk of inelastic
events, and its Q^2 dependence is a very sensitive tool to discriminate between
different models of hadronization. Employing the model of perturbative
hadronization developed earlier, we calculate the Q^2 and x_{Bj} dependences of
the number of collisions and relate it to the mean number of grey tracks, using
an empirical relation obtained from the analysis of data from the Fermilab E665
experiment on DIS of muons off the Xe nucleus. We found the number of grey
tracks to rise steeply with Q^2 in good agreement with the experimental data.
