In Hart v. Wielt (1970) 4 Cal.App.3d 224, the Court of Appeal held that the trial court acted within its discretion in permitting the investigating officer to testify as to his opinion on the reasonable driving speed in the area of the accident. In permitting that testimony, the court "admonished the jury that it was up to the jury to make the final decision as to proper speed and also as to whether the officer was qualified as an expert to give his opinion on speed." (Id. at p. 229.)