  It is known that Lorentz covariance fixes uniquely the current and the
associated guidance law in the trajectory interpretation of quantum mechanics
for spin-1/2 particles. In the nonrelativistic domain this implies a guidance
law for electrons which differs by an additional spin-dependent term from the
one originally proposed by de Broglie and Bohm. Although the additional term in
the guidance equation may not be detectable in the quantum measurements derived
solely from the probability density $\rho$, it plays a role in the case of
arrival-time measurements. In this paper we compute the arrival time
distribution and the mean arrival time at a given location, with and without
the spin contribution, for two problems: 1) a symmetrical Gaussian packet in a
uniform field and 2) a symmetrical Gaussian packet passing through a 1D
barrier. Using the Runge-Kutta method for integration of the guidance law,
Bohmian paths of these problems are also computed.
