  The initial boundary value problem for a class of scalar non autonomous
conservation laws in one space dimension is proved to be well posed and stable
with respect to variations in the flux. Targeting applications to traffic, the
regularity assumptions on the flow are extended to a merely
$\mathbf{L}^{\infty}$ dependence on time. These results ensure, for instance,
the well posedness of a class of vehicular traffic models with time dependent
speed limits. A traffic management problem is then shown to admit an optimal
solution.
