  It is well known that modifications to the Friedmann equation on a warped
brane in an anti de Sitter bulk do not provide any low energy distinguishing
feature from standard cosmology. However, addition of a brane curvature scalar
in the action produces effects which can serve as a distinctive feature of
brane world scenarios and can be tested with observations. The fitting of such
a model with supernovae Ia data (including SN 1997ff at $z\approx1.7$) comes
out very well and predicts an accelerating universe.
