EDMONDS, J.
G. E. Satterlee sued to recover damages for the death of his wife, and also for injury to his person and property resulting from an automobile collision. The principal points relied upon as grounds for a reversal of the judgment in his favor concern two jury instructions stating the legal effect of violation of the Vehicle Code in fixing liability for the accident.
At the time the accident occurred, Satterlee, accompanied by his wife, was driving an automobile in a northerly direction on Citrus Drive. A bus of the school district, operated by Paul Osteraas, was traveling west on Bear Valley Road toward its intersection with Citrus Drive. Prom a point about 60 feet south of Bear Valley Road, for several hundred feet to the south, Citrus Drive had a six per cent ascending grade. [584]*584Bear Valley Road was about level on both sides of Citrus Drive and the streets intersected at approximately a 90 degree angle. Neither of these roads was a through highway, although Citrus Drive carried considerably more traffic than the east and west street. The hard surfaced portion of Bear Valley Road, together with its shoulders, was approximately 29 feet wide; that of Citrus Drive was 32 feet.
As the two drivers approached the corner at about 8 o’clock in the morning, both of them had a clear and unobstructed view of the intersecting road for about 600 feet in each direction. The weather was overcast with a drizzling mist, but this did not affect visibility. Their testimony was in direct conflict as to who first entered the intersection, the relative speeds at which the vehicles were traveling, and the distance of the vehicles from the intersection when each operator first observed the other.
Satterlee declared that he was driving at a speed of about 25 miles per hour, and when he was some 75 to 100 feet south of the intersection he first saw the school bus approaching from his right. The bus then appeared to be about twice as far from the intersection. Satterlee continued on at the “same rate of speed.” He said that he thought he had “worlds of time, ’ ’ that he did not see the bus again until just before the impact, and that he believed he was in the intersection first “because I was so far across.”
Osteraas estimated that prior to reaching Citrus Drive, the speed of the bus was between 30 and 35 miles per hour when, at a point about 195 feet east of the intersection, he looked to his left and saw the Satterlee automobile. It was then some 300 feet south of the intersection traveling north at a speed of between 35 and 45 miles per hour. He realized that if neither vehicle slackened its speed the two would reach the intersection at approximately the same time, but he .expected Satterlee to slow down. He did not see the automobile again until it was too late to avoid the collision. However, he was positive that the bus entered the intersection first, traveling at a speed of 20 to 25 miles per hour.
The testimony of four disinterested witnesses casts considerable doubt upon the bus driver’s account of the accident. They quoted Osteraas as saying that he did not see the Satterlee vehicle until just before the collision; also, that he did not know how the accident happened as the first thing he knew, the car was in front of him and he did not have time [585]*585to stop. According to the evidence, these statements, and other remarks by Osteraas of like import, were made within an hour after the accident.
The point of impact, as estimated by the investigating officer, was approximately one and one-half feet north of the center line of Bear Valley Road and five feet east of the center line of Citrus Drive. Brake marks left by the school bus led up to the point of impact. The marks on the road indicated that the bus had swerved to the right “after the point of impact.” The left front corner of the bus struck the right side of the automobile either over the right front wheel or opposite the right front door.
An instruction requested by the appellants and refused by the trial court reads as follows:
“You are instructed under Section 550 of the Vehicle Code, which is the law of the State of California, provides as follows:
“Vehicle Approaching or Entering Intersection.
“(a) The driver of a vehicle approaching an intersection shall yield the right of way to a vehicle which has entered the intersection from a different highway.
“(b) When two vehicles enter an intersection from different highways at the same time the driver of the vehicle on the left shall yield the right of way to the driver of the vehicle on the right.
“ (c) This section shall not apply to vehicles approaching each other from opposite directions, when the driver of one of such vehicles is intending to or is making a left turn. Such movements shall be governed by Section 551.
“I therefore instruct you that if you find under the evidence that the school bus operated by Paul Osteraas entered the intersection before the vehicle operated by the plaintiff, then I instruct you that it was the duty of the plaintiff to yield the right of way to the school bus, and a failure so to ■ do would constitute negligence on the part of G. B. Satterlee.
“In accordance with the provisions of this section just read to you, I further instruct you that if you find under the evidence that the school bus and the Satterlee vehicle entered the intersection from different highways at the same time, and if you further find that the school bus was to the right of the Satterlee automobile, then I instruct you that it was the duty of the plaintiff to yield the right of way to the school bus and a failure so to do would constitute negligence.
[586]*586“You are therefore instructed that if you find undpr the evidence that the plaintiff violated the provisions of the Vehicle Code, such violation is negligence, and if you further find that such negligence if any proximately contributed in the slightest' degree to the subsequent accident and injury, then your verdict must be in favor of the defendant, Orange Glen School District of San Diego County and against the plaintiff G. E. Satterlee. ’ ’
Upon his own motion the trial judge instructed the jury:
“Now, with reference to .this matter of right of way, I wish to tell you members of the jury that one may have the right of way and yet be negligent. One cannot rely on the right of way arbitrarily and force anyone else off the highway. He cannot barge in and claim the right of way over one whose approach may be a menace to his safety or to the driver of that automobile’s safety. The same test which I have given you‘originally applies in cases on intersections of highways, regardless of who was in the intersection first, and regardless of which automobile is on the right, if they approached at the same time; that is, what would a reasonably prudent person have done under the same or similar circumstances. That applies to both the drivers colliding, whether they approach the intersection at the same time, enter it at the same time, or one entered the intersection first. In other words, these rules of law are not absolute. They must be considered in connection with what would a reasonably prudent person have done under the same or similar circumstances . . .
“I have told you substantially of the rules of law and gave you what is called the basic speed law. I told you that when two automobiles enter an intersection at the same time the automobile or motor vehicle, whether bus or lighter vehicle, on the right, has the right of way, and if one motor vehicle enters an intersection before the other, that motor vehicle has the right of way, but that the right of way is not an absolute right to barge through ignoring any danger to the other motorist or to the barging motorist. One cannot arbitrarily rély on the right of way and expect to scatter from his path all of those who have lesser rights. In other words, the same general rule applies, and the test is: What would a reasonably prudent person do under the same or similar circumstances? It is possible for one who has the right of way to be negligent in the operation of that unquestioned right, under a certain set of circumstances.”
[587]*587The appellants contend that in view of their defense of contributory negligence based upon an asserted violation of section 550 of the Vehicle Code, they were entitled to an unequivocal instruction in the form requested by them. The facts of this case, they insist, do not bring it within the rule that circumstances beyond a plaintiff’s control may excuse violation of the statute. The court’s instruction to the effect that violation of the statute was of no consequence if the plaintiff acted as a reasonably prudent person would act under similar circumstances is also challenged as erroneous. The evidence was evenly balanced upon the issues of negligence and contributory negligence, say the appellants, and as it would support a finding that the bus entered the intersection first, the failure to correctly instruct the jury as to all of the material issues constituted reversible error.
The position of the respondent is that the proposed instruction gives no regard to the circumstances surrounding the accident, such as the speed at which the two vehicles approached the intersection, the attention given by each driver to other traffic, and the respective manner in which the automobile and the bus were operated. Also, the requested instruction does not include as a basis for the jury’s' consideration circumstances which might properly be considered as excusing violation of the statute. In conclusion, says the respondent, the instructions given fully and adequately covered the law applicable to the ease.
The standard of care to which ordinarily one must conform is usually that of the ordinarily prudent or reasonable person under like circumstances. (Civ. Code, §1714; James v. Frazee, 209 Cal. 456 [288 P. 784]; Kelley v. Hodge Transp. System, 197 Cal. 598 [242 P. 76]; Scott v. San Bernardino Valley etc. Co., 152 Cal. 604 [93 P. 677]; Framklin v. Southern Cal. Motor Road Co., 85 Cal. 63 [24 P. 723]; Richardson v. Kier, 34 Cal. 63 [91 Am.Dec. 681]; Fuch v. Werner, 99 Cal.App. 557 [279 P. 183]; Chalmers v. Hawkins, 78 Cal. App. 733 [248 P. 727]; Rest., Torts, § 283.) But the proper conduct of a reasonable person under particular situations may become settled by judicial decision or be prescribed by statute or ordinance.
Traffic rules are statutory standards; for example, a parking requirement (Thomson v. Bayless, 24 Cal.2d 543 [150 P. 2d 413],); direction of traffic on the street (Harris v. John[588]*588son, 174 Cal. 55 [161 P. 1155, Ann.Cas. 1918E 560, L.R.A. 1917C 477]); limitation upon speed (Benjamin v. Noonan, 207 Cal. 279 [277 P. 1045]); Schilling v. Central Cal. Traction Co., 115 Cal.App. 30 [1 P.2d 53]); but section 513 of the Vehicle Code now makes it necessary to establish as a fact that the operation of a vehicle at a greater than prescribed speed constitutes negligence. An act or failure to act below the statutory standard is negligence per se, or negligence as a matter of law. And if the evidence establishes that the plaintiff’s or defendant’s violation of the statute or ordinance proximately. caused the injury and no excuse or justification for violation is shown by the evidence, responsibility may be fixed upon the violator without other proof of failure to exercise due care. (Thomson v. Bayless, supra; Wright v. Los Angeles Ry. Corp., 14 Cal.2d 168 [93 P.2d 135]; Stein v. United Railroads, 159 Cal. 368 [113 P. 663]; Cragg v. Los Angeles Trust Co., 154 Cal. 663 [98 P. 1063, 16 Ann.Cas. 1061]; McKune v. Santa Clara V. M. & L. Co., 110 Cal. 480 [42 P. 980]; Siemers v. Eisen, 54 Cal. 418; Muir v. Cheney Bros., 64 Cal.App.2d 55 [148 P.2d 138]; Samuelson v. Siefer, 62 Cal.App.2d 320 [144 P.2d 879]; Ferguson v. Nakahara, 43 Cal.App.2d 435 [110 P.2d 1091]; Alechoff v. Los Angeles G. & E. Corp., 84 Cal.App. 33 [257 P. 569]; Connell v. Harris, 23 Cal.App. 537 [138 P. 944]; see: Rest., Torts, §§ 285, 286, 288.)
However, in an emergency, or under unusual conditions, it is generally held that circumstances may be shown to excuse the violation. The rule has been aptly stated in Jolley v. Clemens, 28 Cal.App.2d 55, 67 [82 P.2d 51], where it was said (quoting from 1 Shearman & Redfield on Negligence, § 13) : “ . . violation of such a statute or ordinance is presumptive evidence of negligence, which, if not excused by other evidence, including all the surrounding circumstances, should be deemed conclusive . . ” Continuing, the court said: “But unless and until justification or excuse for such conduct appear . . . the general rule applies and it must be treated as negligence per se.” To the same effect is Gallichotte v. California Mut. etc. Assn., 4 Cal.App.2d 503, 505 [41 P.2d 349], where it was stated: “Violation of an ordinance is negligence per se. In Alechoff v. Los Angeles Gas & Electric Corp., 84 Cal.App. 33, 39 [257 P. 569], it is said: ‘It is an axiomatic truth, that every person while violating an express statute, is a wrongdoer, and as such is ex necessitate [589]*589negligent in the eye of the law.’ An act which is performed in violation of an ordinance or statute is presumptively an act of negligence, but the presumption is not conclusive and may be rebutted by showing that the act was justifiable or excusable under the circumstances. Until so rebutted it is conclusive. (Mora v. Favilla, 186 Cal. 199, 202 [199 P. 17]; Rath v. Bankston, 101 Cal.App. 274, 281 [281 P. 1081].)” However, the fact which will excuse the violation of a statute has been defined by the court as one resulting “from causes or things beyond the control of the person charged with the violation.” (4 Cal.App.2d at p. 506. See also: Thomson v. Bayless, supra; Mathers v. County of Riverside, 22 Cal.2d 781 [141 P.2d 419] ; Fennessey v. Pacific Gas & Elec. Co., 20 Cal.2d 141 [124 P.2d 51] ; Johnson v. Griffith, 19 Cal.2d 176 [120 P.2d 6] ; Berkovitz v. American River Gravel Co., 191 Cal. 195 [215 P. 675] ; Squier v. Davis Std. Bread Co., 181 Cal. 533 [185 P. 391] ; Cragg v. Los Angeles Trust Co., supra; Shelby v. Southern Pac. Co., 68 Cal.App.2d 594 [157 P.2d 442] ; Roberts v. Salmon, 66 Cal.App.2d 22 [151 P.2d 556] ; Fietz v. Hubbard, 59 Cal.App.2d 124 [138 P.2d 315] ; Prescott v. City of Orange, 56 Cal.App.2d 144 [132 P.2d 523] ; Finney v. Wierman, 52 Cal.App.2d 282 [126 P.2d 143] ; Henslee v. Fox, 25 Cal.App.2d 286 [77 P.2d 307] ; Scalf v. Eicher, 11 Cal.App.2d 44 [53 P.2d 368] ; Hill v. Peres, 136 Cal.App. 144 [28 P.2d 944] ; Freitas v. Passerino, 131 Cal.App. 585 [21 P.2d 993]; Giorgetti v. Wollaston, 83 Cal.App. 358 [257 P. 109].)
Thus in Rath v. Bankston, supra, where an automobile was parked partly on the highway in violation of the statute, the defendant was allowed to show that, despite reasonably careful inspection, the gasoline supply became exhausted and the car stalled. In another case where a collision occurred with a car which had no taillight, evidence that the light was inspected and found in good order a short time before was held admissible to negative the presumption of negligence. (Berkovitz v. American Gravel Co., supra.) And in Mathers v. County of Riverside, supra, this court reversed a judgment which followed an instruction to the jury that if the plaintiff violated section 525 of the Vehicle Code which requires driving as close as practicable to the right side edge of the road, she was negligent as a matter of law. “Under all of the circumstances of the ease,” said the court, “it should have been left to the jury whether or not the position of her car [590]*590with reference to the white line constituted contributory negligence.” (P. 786.)
A different conclusion was reached where defendant stopped on the roadway side of a parked car to permit his wife to alight. The car behind, in which plaintiff was. riding, collided with defendant’s vehicle. Defendant’s excuse for violation of the prohibition against double parking (Veh. Code § 586) was not accepted, the court holding that the positive mandate of the statute could not be set aside for personal convenience. (Mason v. Crawford, 17 Cal.App.2d 529 [62 P.2d 420].)
In the application of this rule each violation of a statutory requirement must be considered in connection with the surrounding circumstances. Ordinarily, the excuse relied upon by the violator presents a question of fact for the jury’s determination. As stated in Scalf v. Eicher, supra, p. 54: “Whether or not a violation of a statute or ordinance proximately contributed to an accident and whether the violation was excusable or justifiable are questions of fact except in a case where ‘. . . the court is impelled to say that from the facts reasonable men can draw but one inference and that an inference pointing unerringly to the negligence of the plaintiff contributing to his injury.’ ” (See also: Mathers v. County of Riverside, supra; Johnson v. Griffith, supra; Arellano v. City of Burbank, 13 Cal.2d 248 [89 P.2d 113] ; Berkovitz v. American River Gravel Co., supra; Prescott v. City of Orange, supra; Ebert v. Tide Water Assoc. Oil Co., 54 Cal. App.2d 497 [129 P.2d 135] ; Wright v. Ponitz, 44 Cal.App.2d 215 [112 P,.2d 25]; Mecchi v. Lyon Van & Storage Co., 38 Cal.App.2d 674 [102 P.2d 422] ; Osgood v. City of San Diego, 17 Cal.App. 2d 345 [62 P.2d 195].)
But there is, of course, a further question in connection with the issue of negligence. Although a violation of a statute' is not excusable under the particular circumstances of the case, liability is also dependent upon proof that a duty was owed to persons in the class of the plaintiff or the defendant'who is relying upon contributory negligence. (Bateman v. Doughnut Corp. of America, 63 Cal.App.2d 711 [147 P.2d 404] ; Figone v. Guisti, 43 Cal.App. 606 [185 P. 694] ; Corbett v. Spanos, 37 Cal.App. 200 [173 P. 769] ; see: Flynn v. Bledsoe Co., 92 Cal.App. 145 [267 P. 887]; Best., Torts, § 286.) It is also necessary to show that the violation was a proximately contributing cause of the injury. (Burtt v. [591]*591Bank of California, 211 Cal. 548 [296 P. 68] ; Williams v. Southern Pac. Co., 173 Cal. 525 [160 P. 660]; Hitson v. Dwyer, 61 Cal.App.2d 803 [143 P.2d 952] ; Shariah v. Galloway, 19 Cal.App.2d 693 [66 P.2d 185].)
In thé present ease the requested instruction advised the jury that if the school bus entered the intersection before the vehicle operated by Satterlee, his failure to yield the right of way constituted negligence; if the two vehicles entered the intersection at the same time, and the school bus was to the right of the Satterlee vehicle, his failure to yield the right of way constituted negligence; and if Satterlee’s violation of these Vehicle Code sections proximately contributed in the slightest degree to the happening of the accident, the verdict must be in favor of the school district and its driver. But an operator of a motor vehicle cannot arbitrarily rely upon the right of way gained as a result of excessive speed or by other negligent act or violation of the law. (Lindenbaum v. Barbour, 213 Cal. 277 [2 P.2d 161]; Stevenson v. Fleming, 47 Cal.App.2d 225 [117 P.2d 717] ; Miller v. Cranston, 41 Cal.App.2d 470 [106 P.2d 963]; Groat v. Walkup Drayage etc. Co., 14 Cal.App.2d 350 [58 P.2d 200]; see: Page v. Mazzei, 213 Cal. 644 [3 P.2d 11]; Casselman v. Hartford A. & I. Co., 36 Cal.App.2d 700 [98 P.2d 539]; Pattisson v. Cavanagh, 18 Cal.App.2d 123 [63 P.2d 868, 64 P.2d 945]; 136 A.L.R 1497 supplementing annotation in 89 A.L.R. 838.) And although the instruction correctly left the question of fact óf violation to the jury, it invaded the province of the trier of fact by not tendering for consideration the issue as to, whether the circumstances were such as to excuse violation;.. Prom the evidence, the jury reasonably might have found that the bus increased its speed while traveling the 200- feet immediately east of the point of' impact. If, as stated by Satterlee-, when he observed the bus it was about twice as far from the- intersection and traveling at approximately the same speed as his own vehicle, then he reasonably was justified, the jury could have concluded, in assuming that the bus would not dangerously increase its, speed in order to enter the intersection first. Certainly by his own act of increasing speed or “racing for the intersection’'’ an automobile driver should not be allowed to charge the operator of the other vehicle in the collision with negligence per se without the right to prove justification for the statutory violation...
[592]*592Furthermore, the testimony of disinterested witnesses shows that the bus driver, having unimpaired visibility, did not observe the automobile until almost the instant of impact. Under these circumstances it was a question of fact whether Satterlee’s violation of the code provisions, if any, was justifiable or excusable. And although judicial discretion may be exercised in the adoption of a standard of care for the purpose of imposing civil liability, the refused instruction did not afford the jury an opportunity to pass upon the question as to whether the circumstances shown by the evidence afforded excuse or justification. For these reasons, to have instructed the jury in the terms proposed by the appellants would have constituted prejudicial error. (See Mathers v. County of Riverside, supra; Fietz v. Hubbard, supra; Finney v. Wierman, supra; Marston v. Pickwick Stages, Inc., 78 Cal.App. 526 [248 P. 930] ; Hagenah v. Bidwell, 46 Cal.App. 556 [189 P. 799].)
The instruction given by the trial judge upon his own motion presents a more difficult question. He refused to adopt the standard of care established by the Legislature and did not instruct the jury that violation of the statutory standard constituted prima facie evidence of negligence which could be rebutted by evidence of justification or excuse. Instead, upon the issue of contributory negligence, the. court adopted the reasonable man standard of care exclusively, and allowed the jury to determine what constituted due care under the circumstances. The question presented for decision upon this aspect of the case is, therefore, whether the trial court arrived at a proper standard.
By the instruction which adopted the reasonable man standard of care, the jury, in effect, was told that the school district and its driver had the burden of establishing the failure of Satterlee to act as a reasonable man under the circumstances although he had violated a statute and such violation proximately caused the accident. That is not the law. The presumption created by proof of the failure to comply with a statute or ordinance relieves a defendant from the burden of proving that the plaintiff failed to act as a reasonably prudent man. All that the defendant need prove to establish contributory negligence is that plaintiff’s violation of the statute in question proximately caused the accident. Therefore the burden cast upon the defendant where such violation is relied upon, is more easily established than a failure to act as would a reasonably prudent man under similar circum[593]*593stances. If there was a violation of the applicable statute, the burden of going forward is then cast upon the plaintiff, if the defendant is relying upon contributory negligence, to present evidence justifying an excuse for violation. If the jury does not believe that the evidence is sufficient to excuse violation, it must find for the defendant.
For these reasons the adoption by the trial court of the standard of care imposed by a statute or ordinance becomes an important factor in imposing liability. The instruction given by the court on its own motion had the effect of minimizing, if not completely negativing, the code provision. It was, therefore, erroneous and considering the direct conflict in the evidence, constituted “a miscarriage of justice” within the meaning of article VI, section 4% of the California Constitution.
The judgment is reversed.
Gibson, C. J., Shenk, J., Schauer, J., and Spence, J., concurred.