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The kinematic approach to cosmological tests provides a direct evidence tothe present accelerating stage of the universe which does not depend on thevalidity of general relativity, as well as on the matter-energy content of theUniverse. In this context, we consider here a linear two-parameter expansionfor the decelerating parameter, $q(z)=q_0+q_1z$, where $q_0$ and $q_1$ arearbitrary constants to be constrained by the Union supernovae data. By assuminga flat Universe we find that the best fit to the pair of free parameters is($q_0,q_1$) = ($-0.73,1.5)$ whereas the transition redshift is $z_t =0.49^{+0.14}_{-0.07}$ ($1\sigma$) $^{+0.54}_{-0.12}$ ($2\sigma$). Thiskinematic result is in agreement with some independent analyzes andaccommodates more easily many dynamical flat models (like $\Lambda$CDM).

Kinematic Constraints to the Transition Redshift from SNe Ia Union Data