  Using the equation of state of asymmetric nuclear matter that has been
recently constrained by the isospin diffusion data from intermediate-energy
heavy ion collisions, we have studied the transition density and pressure at
the inner edge of neutron star crusts, and they are found to be 0.040 fm^{-3}
<= \rho_{t}<= 0.065 fm^{-3} and 0.01 MeV/fm^{3} <= P_{t} <= 0.26 MeV/fm^{3},
respectively, in both the dynamical and thermodynamical approaches. We have
further found that the widely used parabolic approximation to the equation of
state of asymmetric nuclear matter gives significantly higher values of
core-crust transition density and pressure, especially for stiff symmetry
energies. With these newly determined transition density and pressure, we have
obtained an improved relation between the mass and radius of neutron stars
based on the observed minimum crustal fraction of the total moment of inertia
for Vela pulsar.
