  We present a new sample of 30 nearby (z<0.2) BL Lacs, selected to study the
nuclear as well as the large scale properties of low power radio sources. In
this first paper, we show and discuss new radio data taken with the VLA (19
objects at 1.4 GHz, either in A or C configuration, or both) as well as with
the VLBA (15 sources at 5 GHz). On the kiloparsec scale, all objects exhibit a
compact core and a variety of radio morphologies (jets, halos, secondary
compact components). On the parsec scale, we find weak cores and a few short,
one-sided, jets. From the jet/counter-jet ratio, core dominance, and
synchrotron self Compton model we estimate the intrinsic orientation and
velocity of the jets. The resulting properties of BL Lacs are similar to those
of a parent population composed of FR I radio galaxies.
