The appellants earnestly insist that the trial court erred in denying their motions to dismiss the action of Thomas and the counterclaim of Watson upon compulsory nonsuits under Gr.S. 1-183. They assert the action of Thomas should have been nonsuited for want of evidence of actionable negligence on the part of Dorman in the management of the tractor-trailer combination. They say their motions to dismiss the counterclaim of Watson ought to have been allowed either on the ground that there was no sufficient evidence of actionable negligence on the part of Dorman, or on the ground that Watson was contributorily *129negligent as a matter of law.’ Furthermore, appellants have reserved exceptions to the refusal of the court to grant their prayers for instructions to the effect that there was no evidence of negligence on their part “in reference to the position of the truck on the highway at the time and place of the accident” and that "Watson was guilty of contributory negligence as a matter of law.

We shall address ourselves initially to the inquiry of whether the court erred in refusing to nonsuit the action of Thomas. In passing upon this phase of the appeal, we must be guided by the accepted rule that the question of the liability of a defendant in an action for negligence can be taken from the jury and determined by the court as a matter of law by an involuntary nonsuit only in case the evidence is free from material conflict, and the only reasonable inference to be drawn therefrom is either that there was no negligence on the part of the defendant, or that the negligence of the defendant was not the proximate cause of the plaintiff’s injury. Tysinger v. Dairy Products, 225 N.C. 717, 36 S.E. 2d 246; Montgomery v. Blades, 222 N.C. 463, 23 S.E. 2d 844; Mitchell v. Melts, 220 N.C. 793, 18 S.E. 2d 406; Luttrell v. Mineral Co., 220 N.C. 782, 18 S.E. 2d 412; Reeves v. Staley, 220 N.C. 573, 18 S.E. 2d 239; Murray v. R. R., 218 N.C. 392, 11 S.E. 2d 326; Templeton v. Kelley, 215 N.C. 577, 2 S.E. 2d 696; Ferguson v. Asheville, 213 N.C. 569, 197 S.E. 146; Smith v. Sink, 211 N.C. 725, 192 S.E. 108.

Both Thomas and "Watson presented testimony on the trial tending to show that Dorman, who was admittedly acting within the scope of his authority as an agent of Thurston Motor Lines, operated the tractor-trailer combination upon the public highway on a dark, rainy, and sleety night without displaying thereon burning rear and clearance lights as required by G.S. 20-129, which was enacted by the General Assembly to minimize the hazards incident to the movement of motor vehicles upon the public roads during the nighttime. If Dorman did this, he was guilty of negligence per se. Page v. McLamb, 215 N.C. 789, 3 S.E. 2d 275; Clarke v. Martin, 215 N.C. 405, 2 S.E. 2d 10; Cook v. Horne, 198 N.C. 739, 153 S.E. 315. This would be so irrespective of whether the tractor-trailer combination was disabled on the paved portion of the highway within the meaning of subsection c of G.S. 20-Í.61 at the time of the collision.

There was also testimony tending to show that the tractor and trailer were parked on the premises of the Tar Heel Service Station on the west of the highway just before the collision; that Dorman put the tractor into motion and attempted to pull the inert trailer and its cargo, weighing-22,500 pounds in the aggregate, across the pathway of the oncoming Plymouth with a view to reaching the northbound traffic lane and resuming his northward journey; and that Dorman did this notwithstanding *130the fact that he saw the Plymouth “coming from the north” at the very moment he drove the tractor-trailer combination “out of the service station.” This testimony was ample to warrant the conclusion that Dorman was negligent at the time and place in controversy in that he proceeded onto the highway and into the path of the approaching Plymouth coupe with the tractor and trailer when he knew, or by the exercise of reasonable care would have known that he could not cross in front of the Plymouth in safety. Ingram v. Smoky Mountain Stages, Inc., 225 N.C. 444, 35 S.E. 2d 337; Fowler v. Underwood, 193 N.C. 402, 137 S.E. 155; 5 Am. Jur.; Automobiles, section 306.

It has been noted that the only witness at the trial claiming any personal knowledge as to when, how or why the tractor-trailer combination came to a standstill on the paved portion of the highway was the defendant Dorman, who attributed the event solely to the unexplained stopping of the engine of the tractor. There was testimony on the trial indicating that the tractor-trailer combination was under the exclusive management of Dorman, the admitted agent of Thurston Motor Lines, when it stalled and obstructed the highway by reason of the unexplained stopping of the engine of the tractor; that such an engine does not stop in the ordinary course of things when according to its mechanical construction it ought to remain in operation except by reason of some defect in' the machine or negligence in its operation; and that the engine and the other parts of this tractor-trailer combination were in perfect mechanical condition when the unexplained stopping of the engine took place. While they did not require any such conclusion, these circumstances were sufficient to permit an inference by the jury that the stopping of the engine and the resultant stalling of the-tractor-trailer combination arose from a want of due care on the part of Dorman in the operation of the tractor. Boone v. Matheny, 224 N.C. 250, 29 S.E. 2d 687; Etheridge v. Etheridge, 222 N.C. 616, 24 S.E. 2d 477; Howard v. Texas Co., 205 N.C. 20, 169 S.E. 832; Springs v. Doll, 197 N.C. 240, 148 S.E. 251; Ramsey v. Power Co., 195 N.C. 788, 143 S.E. 861; Ridge v. R. R., 167 N.C. 510, 83 S.E. 762, L.R.A. 1917E, 215; Isley v. Bridge Co., 141 N.C. 220, 53 S.E. 841; Liberatore v. Town of Framingham, 315 Mass. 538, 53 N.E. 2d 561; Glaser v. Schroeder, 269 Mass. 337, 168 N.E. 809; Doryk v. Perth Amboy Bottling Co., 104 N.J.L. 87, 139 A. 419; Blashfield’s Cyclopedia of Automobile Law and Practice (Perm. Ed.), 6043; 45 C.J., Negligence, section 768; 38 Am. Jur., Negligence, section 295.

Furthermore, it cannot be said as a matter of law that Dorman acted as an ordinarily prudent person would have acted under the same or similar circumstances after the tractor and trailer came to a standstill on the paved portion of the highway. There was testimony indicating that the lighting system of the tractor-trailer combination was in perfect *131mechanical condition, but that the rear and clearance lights were not burning. The jury might well have inferred that due care under the existing circumstances would have prompted Dorman to turn on the rear and clearance lights as a warning to approaching motorists of the impending peril, and that he failed to do so. Pender v. Trucking Co., 206 N.C. 266, 173 S.E. 336.

Whether Dorman was negligent in any of these respects, and whether such negligence constituted the proximate cause or one of the proximate causes of personal injury to Thomas were fact questions. Conley v. Pearce-Young-Angel Co., 224 N.C. 211, 29 S.E. 2d 740; Quinn v. R. R., 213 N.C. 48, 195 S.E. 85; Yates v. Chair Co., 211 N.C. 200, 189 S.E. 500; Thurston v. R. R., 199 N.C. 496, 154 S.E. 836. This is true even with respect to the testimony indicating a failure on the part of Dorman to display burning rear and clearance lights conforming to G.S. 20-129. The trailer was “jack-knifed” across the highway at “almost a 45 degree angle” with its left side in the pathway of the southbound Plymouth, and it cannot be asserted with dogmatism that there was no causal relation between the alleged unlighted rear and clearance lights -and the collision. It follows that the court properly submitted to the jury the question of whether Thomas suffered personal injury as the proximate consequence of negligence on the part of Dorman. Barrier v. Thomas and Howard Co., 205 N.C. 425, 171 S.E. 626. This conclusion would not be altered if Watson had been guilty of concurrent negligence constituting one of the proximate causes of the injury sustained by Thomas. Such negligence on the part of Watson would not be imputed to Thomas, an invited guest having no interest in the Plymouth and no control over its driver. Sample v. Spencer, 222 N.C. 580, 24 S.E. 2d 241; Dillon v. Winston-Salem, 221 N.C. 512, 20 S.E. 2d 845; Harper v. R. R., 211 N.C. 398, 190 S.E. 750; Gaffney v. Phelps, 207 N.C. 553, 178 S.E. 231; Keller v. R. R., 205 N.C. 269, 171 S.E. 73.

What has been said compels the adjudication that the court did not err in refusing to charge that there was no evidence of negligence on the part of Dorman and the Thurston Motor Lines “in reference to the position of the truck on the highway at the time and place of the accident,” or in denying the motion to nonsuit the counterclaim of Watson upon the specific ground that there was no sufficient evidence of actionable negligence on the part of Dorman.

This brings us to a consideration of the question of whether the trial court ought to have nonsuited the counterclaim of Watson or directed a verdict thereon for appellants upon the ground that Watson, who occupied the status of a plaintiff in respect to his counterclaim, was eontribu-torily negligent as a matter of law. Appellants invoke the long line of cases beginning with Weston v. R. R., 194 N.C. 210, 139 S.E. 237, and *132ending with Bus Co. v. Products Co., 229 N.C. 352, 49 S.E. 2d 623, declaring either expressly or impliedly that “it is negligence as a matter of law to drive an automobile along a public highway in the dark at such a speed that it cannot be stopped within the distance that objects can be seen ahead of it.” The appellants assert on the basis of these decisions that the testimony as a whole compels the single conclusion that Watson proximately contributed to his own misfortune by outrunning his headlights.

Few tasks in trial law are more troublesome than that of applying the rule suggested by the foregoing quotation to the facts in particular cases. The difficulty is much enhanced by a tendency of the bench and bar to regard it as a rule of thumb rather than as an effort to express in convenient formula for ready application to a recurring factual situation the basic principle that a person must exercise ordinary care to avoid injury when he undertakes to drive a motor vehicle upon a public highway at night. The rule was phrased to enforce the concept of the law that an injured person ought not to be permitted to shift from himself to another a loss resulting in part af least from his own refusal or failure to see that which is obvious. But it was not designed to require infallibility of the nocturnal motorist, or to preclude him from recovery of compensation for an injury occasioned by collision with an unlighted obstruction whose presence on the highway is not disclosed by his own headlights or by any other available lights. When all is said, each case must be decided according to its own peculiar state of facts. This is true because the true and ultimate test is this : What would a reasonably prudent person have done under the circumstances as they presented themselves to the plaintiff? Blashfield’s Cyclopedia of Automobile Law and Practice, sections 741, 751.

In ruling on a motion for nonsuit, the court takes it for granted that the evidence favorable to the plaintiff is true and resolves all conflict of testimony in his favor. Bundy v. Powell, 229 N.C. 707, 51 S.E. 2d 307. When this is done i-n this litigation, it becomes plain that there was evidence on the trial sufficient to establish the matter stated in the next succeeding paragraph..

Watson unexpectedly encountered the rain and sleet en route home. He was not bound as a matter of law to stop and wait for the storm to subside or for daylight to come in order to escape the imputation of contributory negligence. Indeed, he might reasonably have inferred that even a temporary stopping of the Plymouth and the resultant partial blocking of the icy roadway would magnify rather than minimize existing perils. He elected to proceed homeward. In so doing, he acted with the utmost caution on account of the inclement state of the weather and road. He traveled exclusively upon his right-hand half of the highway *133at a speed of only 20 miles per bour. As be approached tbe place of collision, Watson saw tbe beadligbts of tbe tractor shining along tbe northbound traffic lane in such a manner as to indicate that tbe tractor was moving northward on its own side of tbe road, and drew an inference from this fact and tbe other attending circumstances that be was meeting and about to pass another motor vehicle proceeding in tbe opposite direction along bis left-hand half of tbe highway. Indeed, Watson’s conclusion that tbe tractor, was in motion may well have been in complete accord with actuality up to a split second before tbe collision for Dorman admitted that be saw tbe lights of tbe oncoming Plymouth as be “pulled out of tbe service station” to continue bis journey to tbe north. As be bad no notice of any kind to tbe contrary, Watson bad a right to act on tbe assumption that Dorman would not operate a tractor-trailer combination on tbe highway at night without ■ displaying thereon all tbe lights required by law. Since tbe descending rain and sleet impaired his vision, Watson drove with bis beadligbts tilted downward in order to better bis capacity to see and to avoid projecting a glaring light into tbe faces of tbe motorists be was meeting. As be neared tbe place of tbe accident, Watson could observe everything perfectly up to tbe beadligbts of tbe tractor, but be could not see anything beyond such headlights “except blackness which be took to be night.” His inference that nothing except “night” lurked in bis path beyond tbe beadligbts of tbe tractor was reasonable because tbe dark colored and unligbted trailer was spattered with mud, and covered with sleet, and blended with tbe surrounding darkness, rain, and sleet. These circumstances in combination with tbe falling rain and sleet and tbe 3 or 4 feet of space between tbe surface of tbe road and tbe bottom of tbe unligbted trailer prevented tbe beadligbts of tbe Plymouth from “picking-up” tbe trailer and disclosing its presence on tbe highway to Watson until tbe collision bad become inevitable.

Manifestly, this testimony was sufficient to warrant a finding by tbe jury that Watson acted as a reasonably prudent person would have done under tbe circumstances as they presented themselves to him at tbe time and place of tbe accident. In consequence, tbe court properly denied tbe motions of tbe appellants to nonsuit bis counterclaim on tbe theory that be was contributorily negligent as a matter of law. Barlow v. Bus Lines, 229 N.C. 382, 49 S.E. 2d 793; Cummins v. Fruit Co., 225 N.C. 625, 36 S.E. 2d 11; Cole v. Koonce, 214 N.C. 188, 198 S.E. 637; Williams v. Express Lines, 198 N.C. 193, 151 S.E. 197.

This conclusion compels tbe further ruling that tbe court rightly refused to give tbe jury tbe instruction requested by appellants to tbe effect that they would be entitled to contribution from Watson as a matter of law in case of any recovery against them by Thomas.

*134We have carefully considered the exceptions of appellants to the charge, and have concluded that none of them can be sustained.

The trial and judgment will be upheld for we find in law

No error.

dissents only as to defendant Watson for the reason he is of the opinion said defendant was guilty of contributory negligence as a matter of law.