In opposition to the motion, defendant asserted that he was driving his vehicle within the speed limit, maintaining a 15-foot distance between his vehicle and plaintiffs in traffic that was "moving well," when plaintiff's vehicle suddenly stopped without warning. Absent any indication from defendant about his speed, the only permissible inference is that 15 feet was not a safe distance in traffic that was "moving well" ( see Vehicle and Traffic Law § 1129 [a]; Johnson v Phillips, 261 AD2d 269, 271). Defendant's assertion that plaintiff suddenly stopped because plaintiff was tailgating a vehicle in front of him is speculation.