The Speeding Chauffeur

Action for damages that allegedly occurred when D's car collided with B's car, swerved up on the sidewalk, and struck P, who was walking on the sidewalk. D's car was driven by D, but B's car was driven by his chauffeur, Jeeves, who was alone in the car. D's answer denies he was negligent and alleges the accident was totally Jeeves's fault. At trial,B is unavailable. D offers W to testify that a month before trial W heard B say that Jeeves was driving so fast at the time of the accident that he ran a stop sign. P objects. What ruling and why?