Defendants aver that plaintiff was contributorily negligent, and that his negligence consists, among other things, of having turned his vehicle to the left without ascertaining that such movement could be made in safety, and of having failed to give a signal of his intention to make the turn. G.S. 20-154(a).
The presiding judge instructed the jury as to the legal meaning of negligence and proximate cause, read and explained pertinent statutory provisions, including G.S. 20-154(a), and recapitulated the evidence. In giving final instructions on the second, or contributory negligence, issue, he charged: “. . . if the defendant has satisfied you from the evidence and by its greater weight that the plaintiff while driving along Highway 343, turned his automobile from the right lane of travel across the highway to his left, without first seeing that such movement could be made in safety and without first giving a signal, either mechanical or hand signal, to any vehicle which might have been affected by such turning from a direct line of travel, then such failure to give such signal would have constituted negligence per se, that is within itself, and if you find that the plaintiff failed to give such signal and you further find that as a proximate cause of such failure an accident resulted in which the plaintiff was injured, then you would answer the SECOND ISSUE ‘YES’.”
*440Defendants contend that this instruction is erroneous and entitles them to a new trial. We agree.
The instruction states that defendants, as prerequisite for a favorable answer to the second issue, must satisfy the jury by the greater weight of the evidence that the collision was proximately caused both by the failure of plaintiff to ascertain that he could make a left turn in safety before making such movement and the failure of plaintiff to give the statutory signal of his intention to make the turn. It states in substance that defendants must first prove that plaintiff failed to ascertain safe turning conditions and, having proved this, must go further and prove that plaintiff failed to signal his intention to turn, and that the failure to signal was the proximate cause of the collision.
The instruction places an unwarranted burden on defendants. This Court has said that under G.S. 20-154 (a) “any person who undertakes to drive a motor vehicle upon a highway must exercise reasonable care to ascertain that such movement can be made in safety before he turns either to the right or the left from a direct line. Besides he is required by the same statute to signal his intention to turn in the prescribed manner and for the specified distance before changing his course ‘whenever the operation of any other vehicle may be affected by such movement.’ A motorist... is negligent as a matter of law if he fails to observe either of these statutory precautions . . . and his negligence in such respect is actionable if it proximately causes injury to another.” (Emphasis added.) Grimm v. Watson, 233 N.C. 65, 67, 62 S.E. 2d 538. It is true that the judge, earlier in the charge, in explaining the applicable statute, expressly stated the substance of the above quotation from Grimm. But “it is elementary that where there are conflicting instructions with respect to a material matter — one correct and the other not — a new trial must be granted, as the jurors are not supposed to know which one is correct, and we cannot say they did not follow the erroneous instruction.” Hubbard v. R. R., 203 N.C. 675, 679, 166 S.E. 802. Moreover, the challenged instruction is the crux of the charge on the contributory negligence issue. It is the final and summary direction to the jury as to the burden defendants must carry in order to prevail on this issue. It is at this juncture that the court succinctly applies the law to the facts. The error lies at the heart of the charge and compels a new trial.
We think also that the court erred in failing to submit an issue as to agency. William Leon White, Jr., was driving the automobile of his father and codefendant, William Leon White, Sr. It was stipulated that White, Sr., was the owner, but it was denied that White, Jr., was operating the vehicle as the agent and about the business of the owner.
G.S. 20-71.1 creates a rule of evidence. It has no other or further *441force or effect. Proof of registration or admission of ownership furnishes, by virtue of the statute, prima facie evidence that the driver is agent of the owner in the operation, and is sufficient to support, but not compel, a verdict on the agency issue. It takes the issue to the jury. Even so, plaintiff must allege, and has the burden of proving, agency. Hartley v. Smith, 239 N.C. 170, 79 S.E. 2d 767.
“It is the duty of the trial court, either of its own motion or at the suggestion of counsel, to submit such issues as are necessary to dispose of all material controversies arising on the pleadings and support a final judgment. Within this limitation, the form and number of the issues are within the sound discretion of the trial court.” 4 Strong: N. C. Index, Trial, § 40, p. 347; Baker v. Construction Corp., 255 N.C. 302, 121 S.E. 2d 731.
Defendants did not tender an agency issue. The court undertook to submit the matter to the jury on the first, or negligence, issue. We do not suggest that this was impossible, but it does present difficulties. The court’s instructions on the legal principles involved are not entirely free of error, and there are no directions as to how the jury might indicate that there was no agency in the event it so found and also found that White, Jr., was guilty of actionable negligence. The only alternative, under the instructions as given, was to either find that both defendants were negligent as alleged or that neither was. Under the issues submitted and instructions given it cannot be said with certainty that the agency issue has been decided. Therefore the answers to the issues submitted are not sufficiently definite to support a judgment against William Leon White, Sr.
New trial.
WlNBORNE, C.J., not sitting.