Martin (P) was driving his buggy on the night of August 21, 1915. P was killed in a collision between his buggy and Herzog's (D) car. It was dark when the accident occurred. P was driving without lights and D did not keep to the right of the center of the highway. P alleged that D was driving on the wrong side of the road. D claimed that P was contributorily negligent for failing to drive without headlights as required under the law. In the body of the charge, the trial judge said that the jury could consider the absence of light 'in determining whether the plaintiff's intestate was guilty of contributory negligence in failing to have a light upon the buggy as provided by law. I do not mean to say that the absence of light necessarily makes him negligent, but it is a fact for your consideration.' D requested a ruling that the absence of a light on the plaintiff's vehicle was 'prima facie evidence of contributory negligence.' This request was refused, and the jury were again instructed that they might consider the absence of lights as some evidence of negligence, but that it was not conclusive evidence. P then requested a charge that 'the fact that the plaintiff's intestate was driving without a light is not negligence in itself,' and to this, the court acceded. The jury was instructed that they were at liberty to treat the omission of the lights either as innocent or as culpable. The jury gave the verdict to P. The Appellate Division reversed that verdict. P appealed to the court of appeals.