The effect of the light group velocity reduction in dielectric Bragg reflection waveguide structures (SiO2/TiO2) in the vicinity of the cutoff frequency is studied experimentally. The effect of antimirror reflection specific to Bragg reflection waveguides is described and employed to detect slow light. Experiments were performed using Ti:sapphire laser pulses ~100 fs in length. The group index ng ~ 30 with a fractional pulse delay (normalized to the pulse width) of ~10 is demonstrated. The problems and prospects of the implementation of slowlight devices based on Bragg reflection waveguide structures are discussed.