A trail is a walk on a lattice that may visit a site more than once but a bond at most once. We have carried out transfer-matrix studies of trails on the square lattice and of hybrid walks that interpolate between self-avoiding walks and trails. The results are in agreement with the same universal exponents as self-avoiding walks. However, the finite-size corrections are much larger than for self-avoiding walks. An explanation in terms of an irrelevant variable with scaling index is given.