In Hardin v. San Jose City Lines, Inc. (1953) 41 Cal.2d 432, the court instructed the jury about both the basic speed law and the prima facie speed limit where there was evidence a bus on which the plaintiff was injured was traveling in excess of the posted speed limit in a medium amount of traffic when it came to a sudden stop. The court stated it is proper in a civil case "to give an instruction on the prima facie speed limit even though proof of speed in excess of that limit is not enough, standing alone, to show that the vehicle was being operated negligently." (Id. at p. 439.) The court discussed former Vehicle Code section 513 (predecessor statute to Veh. Code, 40831), stating proof of speed in excess of a prima facie speed limit in a civil case does not establish negligence as a matter of law and it is necessary to establish as a fact that "'such excess speed'" constituted negligence. The court concluded, since "the words 'such excess speed' clearly refer to an excess over the prima facie limit . . . it follows that the plaintiff may introduce evidence of the prima facie speed limit in order to show that there was 'such excess speed." (Hardin, supra, at p. 439.) It was in this context the court stated, "the prima facie speed limit is a factor to be considered with other pertinent factors and that the plaintiff is entitled to an instruction thereon." (Ibid.)