Opinion by
Mr. Justice Bell,Was defendant’s negligence the proximate cause of the accident, or did the acts of plaintiff’s husband break the causal connection and become the superseding cause of the accident?
Considering the evidence in the light most favorable to plaintiffs, as we must on a motion for judgment non obstante veredicto, these are the facts:
Clara Listino was a passenger in the car driven by her husband proceeding south on Sproul Boad — a wide concrete two lane highway — at about 30 to 35 miles an hour, on the evening of November 21, 1952. The night was dark and rainy with no street lights where the accident occurred. Defendant was repairing the Sproul Road, and at a point 300 feet from the accident the travelable concrete portion of Sproul Road narrowed abruptly on plaintiff’s side of the highway. There were no signs, flares, barricades or other warnings to indicate this abrupt reduction in width. Plaintiff, Aleardo Listino, knew that the Sproul Road was being repaired and before the accident had on two occasions driven past other portions which were being reconstructed. Listino drove his car off the concrete highway on to that portion of the highway which was being repaired. He felt the right wheels of his car hit mud ruts. He estimated that his car traveled in the mud about 30 feet before he was able to swerve it back on to the paved concrete portion of the highway. Approximately 270 feet from where plaintiff got back on to the concrete portion of Sproul Road, he crossed the road and was struck on the opposite side of the road sidewise, i.e. in a right angle collision, by oncoming traffic. At ño timé did he put on his brakes, ñor did *35he know whether his car skidded after he got it back onto the concrete portion of the highway. His best testimony was that he was fighting the wheel; he saw three cars coming the opposite way, then he blacked ont. Clara Listino did not remember anything about the accident.
Plaintiffs produced Officer Ruthers who investigated the accident as a result of a telephone call. He testified as follows:
“There was a Studebaker sedan [plaintiff’s car] crosswise in the northbound lane of traffic.* We were heading south on Sproul Road, Pennsylvania Route 320. It set in a position approximately 100 yards south of where the newr part of Sproul Road had been widened, where that point ended, and a point midway in the intersection of Springfield and Sproul Road. It had been struck by a car proceeding northbound on Sproul Road, a Chevrolet sedan . . . some of the mud and debris that was dragged by Mr. Listino’s car from the southbound lane of the highway across in an arc to the northbound lane of the highway at the point of impact.”
Immediately after the accident the officer took measurements and made a sketch of Sproul Road.
Briefly summarizing the situation, Listino was driving south on Sproul Road; when the road narrowed he ran off the paved portion; his right wheels ran along muddy ruts; he regained the concrete portion of the Sproul Road after running in the ruts for 30 feet; he then drove 270 feet in his right lane; then for reasons unknown or undisclosed he crossed over into the left northbound lane and was struck in a right angle collision by traffic in that lane.
*36It is hornbook law that plaintiff has the burden of proving that defendant’s negligence was the proximate cause of the accident: DeLuca v. Manchester Laundry and Dry Cleaning Company, Inc., 380 Pa. 484, 112 A. 2d 372; Helm v. South Penn Oil Co., 382 Pa., 437, 114 A. 2d 909; Lanni v. Pa. R. R. Co., 371 Pa. 106, 88 A. 2d 887; Brusis v. Henkels, 376 Pa. 226, 102 A. 2d 146. His evidence failed to sustain this burden. There was no affirmative evidence and no evidence from which it could reasonably be inferred that Listino’s driving for 30 feet in soft mud ruts 300 feet from the accident, caused him 270 feet later to pull over at that point crosswise in front of oncoming traffic in the other lane.
The law on the subject of intervening acts and superseding cause is difficult to formulate because so many varied situations can and do arise, and for these reasons it has not always been uniformly expressed.*
The question boils down to whether the chain of causation was broken and superseded by an intervening act.
Perhaps the best expression of the principle in question is found in DeLuca v. Manchester Laundry and Dry Cleaning Company, Inc., 380 Pa., supra. In that case a judgment non obstante veredicto was entered by this Court upon the ground that an intervening act of negligence was the superseding cause of the accident. Chief Justice Stern said (pages 488-492) :
*37“. . . assuming, arguendo, that the Laundry Company was guilty of a violation of the provisions of the statute and therefore negligent per se, such negligence was not a ground of liability unless it was the proximate and efficient cause of the accident in question: Hayes v. Schomaker, 302 Pa. 72, 77, 152 A. 827, 829; Hutchinson v. Follmer Trucking Company, 333 Pa. 424, 427, 5 A. 2d 182, 183; Shakley v. Lee, 388 Pa. 476, 478, 84 A. 2d 322, 323; Purol, Inc. v. Great Eastern System, Inc., 130 Pa. Superior Ct. 341, 344, 345, 197 A. 543, 544, 545; Vunak v. Walters, 157 Pa. Superior Ct. 660, 662, 43 A. 2d 536, 537. This is because an act of negligence which creates merely a passive background or circumstance of an accident does not give rise to a right of recovery if the accident was in fact caused by an intervening act of negligence which is a superseding cause: Stone v. Philadelphia, 302 Pa. 340, 153 A. 550; Schwartz v. Jaffe, 324 Pa. 324, 332, 188 A. 295, 298; Kline v. Moyer and Albert, 325 Pa. 357, 191 A. 43; Ashworth v. Hannum, 347 Pa. 393, 397, 398, 32 A. 2d 407, 408; Venorick v. Revetta, 152 Pa. Superior Ct. 455, 83 A. 2d 655.
“The question, then, is whether the parking of the Laundry Company’s truck, even if it were a violation of the statute and therefore an act of negligence, was a proximate or only what the law regards as a remote cause of plaintiff’s accident. . . .
“In Kline v. Moyer and Albert, 325 Pa. 357, 191 A. 43, a truck was negligently parked on the highway in the dusk of a late afternoon. A car in which the plaintiff was a guest rider started to pass the standing truck when another automobile coming in the opposite direction swerved from the rear of the truck and struck plaintiff’s car in a head-on collision. The question in the case was whether a cause of action could be maintained against the driver of the standing truck or *38whether his negligence had been superseded by that of the driver of the automobile which struck plaintiff’s car.* It was held that if the driver of the car saw and knew of the position of the standing truck and nevertheless thereafter proceeded negligently, with the result that the accident occurred, the original negligence of the driver of the truck had become a non-causal factor divested of legal significance; as to it the chain of causation had been broken and responsibility remained solely with the operator of the offending car. The applicable principle was formulated as follows: ‘Where a second actor has become aware of the existence of a potential danger created by the negligence of an original tortfeasor, and thereafter, by an independent act of negligence, brings about an accident, the first tortfeasor is relieved of liability, because the condition created by him was merely a circumstance of the accident and not its proximate cause.’. . .
“Ordinarily the question whether the negligence of a defendant is a proximate cause of the accident is for the fact-finding tribunal (Landis, Administratrix v. Conestoga Transportation Company (No. 1), 349 Pa. 97, 100, 36 A. 2d 465, 466), but where the relevant facts *39are not in dispute and the remoteness of the causal connection between defendant’s negligence and plaintiff’s injury clearly appears from the evidence the question becomes one of law and, as such, is within the scope of appellate review: Rugart v. Keebler-Weyl Baking Co., 277 Pa. 408, 414, 121 A. 198, 200; Leoni v. Reinhard, 327 Pa. 391, 396, 194 A. 490, 492; Irwin Savings & Trust Company v. Pennsylvania R.R. Co., 349 Pa. 278, 283, 37 A. 2d 432, 434; Frisch v. Texas Company, 363 Pa. 619, 621, 622, 70 A. 2d 290, 291, 292; Roche v. Pennsylvania R.R. Co., 169 Pa. Superior Ct. 48, 57, 82 A. 2d 332, 337....”
Aleardo Listino’s own negligence was in the words of Chief Justice Stern “the proximate and efficient cause of the accident . . . the original negligence of [Union Paving Company] had become a non-causal factor divested of legal significance; as to it the chain of causation had been broken and responsibility remained solely with the operator of the offending car.”
The judgment in favor of Clara Listino is reversed and is here entered for the defendant, Union Paving Company.
Italics, ours.
Cf. DeLuca v. Manchester Laundry and Dry Cleaning Company, Inc., 380 Pa. 484, 112 A. 20 372; Mastrocinque v. McCann, 385 Pa. 33, 122 A. 2d 55; KUne v. Moyer and Albert, 325 Pa. 357, 191 A. 43; Roadman v. Bellone, 379 Pa. 483, 108 A. 2d 754; Brusis v. Henkels, 376 Pa. 226, 102 A. 2d 146; Helm v. South Penn Oil Co., 382 Pa. 437, 114 A. 2d 909; Coleman v. Dahl, 371 Pa. 639, 92 A. 2d 678. Cf. also Restatement, Torts.
The most recent example of superseding cause is found in Mastrocinque v. McCann, 385 Pa., supra. In that case, the plaintiff’s decedent was a passenger in the automobile of the additional defendant. The additional defendant illegally parked his automobile on a downgrade slope of a state highway. Plaintiff’s decedent got out of the car and stood behind this car on the highway to relieve himself. The car of the original defendant approached from the rear, skidded and struck and killed plaintiff’s decedent. Plaintiff contended that negligence of the additional defendant, i.e. his illegal parking, was a concurrent cause of the accident. This Court held that the intervening act of the original defendant was the superseding and consequently the sole proximate cause of the accident, and entered a judgment non obstante veredicto in favor of the additional defendant.