Relativistic tunneling times for Gaussian wave packets

We investigated an average tunneling time, as suggested by the Salecker-Wigner-Peres clock, for a localized particle described by the Dirac equation. Then we evaluate this average transmission time for a Gaussian wave packet incident on a square barrier. It was found that the time does not saturate for large barriers, that is, the average time doesn't suffer from the Hartmann effect. We also consider the contribution of the negative energy components of the localized wave packet for the average time.