We discuss observational constrains coming from supernovae imposed on the behaviour of the Randall-Sundrum models . We test the models using the Perlmutter SN Ia data as well as the new Knop and Tonry/Barris samples . The data indicates that , under the assumption that we admit zero pressure dust matter on the brane , the cosmological constant is still needed to explain current observations . We estimate the model parameters using the best-fitting procedure and the likelihood method . The observations from supernovae give a large value of the density parameter for brane matter \Omega _ { \lambda, 0 } \simeq 0.01 as the best fit . For high redshifts z > 1.2 , the difference between the brane model and the \Lambda CDM ( Perlmutter ) model becomes detectable observationally . From the maximum likelihood method we obtained the favored value of \Omega _ { \lambda, 0 } = 0.004 \pm 0.016 for \Omega _ { k, 0 } = 0 and \Omega _ { \mathrm { m } , 0 } = 0.3 . This gives the limit \Omega _ { \lambda, 0 } < 0.02 at 1 \sigma level . While the model with brane effects is preferred by the supernovae type Ia data , the model without brane fluid is still statistically admissible . We also discuss how fit depends on restrictions of the sample , especially with respect to redshift criteria . We also pointed out the property of sensitive dependence of results with respect to choice of { \cal M } parameter . For comparison the limit on brane effects which comes from CMB anisotropies and BBN is also obtained . The uncertainty in the location of the first peak gives a stronger limit \Omega _ { \lambda, 0 } < 1.0 \cdot 10 ^ { -12 } , whereas from BBN we obtain that \Omega _ { \lambda, 0 } < 1.0 \cdot 10 ^ { -27 } . However , both very strict limits are obtained with the assumption that brane effects do not change the physics in the pre-recombination era , while the SN Ia limit is model independent . We demonstrate that the fit to supernovae data can also be obtained if we admit the phantom matter p = - ( 4 / 3 ) \varrho on the brane , where this matter mimics the influence of the cosmological constant . We show that phantom matter enlarges the age of the universe on the brane which is demanded in cosmology . Finally , we propose to check for dark radiation and brane tension by the application of the angular diameter of galaxies minimum value test .