Opinion by
Mr. Justice Eagen,Sylvia Vaughn was a passenger in an automobile operated by her husband, Clarence Vaughn, when it ran into the rear end of a street car. Personal injuries resulted. This action for damages followed wherein the Philadelphia Transportation Company was named defendant. Clarence Vaughn was then brought on the record as an additional defendant. After trial, the jury returned a verdict in favor of the wife-plaintiff in the sum of $20,000 against both defendants jointly. Post trial motions filed on behalf of the original defendant were dismissed. From the judgment entered on the verdict, the original defendant appeals.
The street car involved had two yellow lights on the rear thereof with the word “s-t-o-p” printed on each light. If functioning properly, these lights would go on automatically when the brakes of the street car were applied. Two additional red lights were also located on the rear of the street car.
The plaintiffs’ evidence established that, as the street car approached the intersection where the collision occurred, it was traveling at a rate of speed approximating 25 to 30 miles per hour; that the Vaughn automobile, traveling in the same direction at about the same speed, was approximately 30 feet to the rear; that the street car, suddenly and without warning, came to a stop when the intersection light changed from green to cautionary yellow; that the stop-warning signal-lights on the rear of the street car failed to function or to illuminate; and, that the Vaughn automobile ran into the rear of the street car.
*466In answer to the above, tbe traction company offered evidence to prove tbat the street car came to a gradual and slow stop at tbe intersection; tbat it bad been stopped for about 15 seconds before tbe Vaughn automobile struck it in the rear and pushed it forward fifteen feet; tbat tbe stop-warning signal-lights were functioning properly, and were still on immediately after tbe accident, and also were functioning properly when tbe street car bad previously left tbe barn.
On this record, tbe question of tbe traction company’s negligence was strictly a jury question, although error in tbe charge of tbe trial court requires tbe grant of a new trial.
Plaintiffs contended at trial tbat tbe operator of tbe street car was negligent in not giving a band or mechanical signal of tbe intention to stop, as required by tbe provisions of Article X, §1012 of Tbe Vehicle Code, Act of May 1, 1929, P. L. 905, as amended, 75 P.S. §1012. In line with this position, tbe trial court charged tbe jury, inter alia, as follows: “Now, tbe duty which tbe law imposes upon tbe defendant, PTC, is as follows. Our Vehicle Code provides tbat tbe driver of any vehicle upon tbe highway, before starting, stopping and turning shall first see tbat such movement can be made in safety. Tbat is, members of tbe jury, our Vehicle Code provides for tbe giving of a band or a mechanical signal of an intention to start, stop or turn from a direct line of travel. This section of our Code requires tbat such signal be plainly visible to an approaching or following vehicle whenever tbe operation of such vehicle may be affected by such stopping, starting or turning.”
Tbe relevant section of Tbe Vehicle Code, supra, requiring a signal to be given of an intention to stop, etc., applies to “vehicles”, but tbe code is clear tbat “vehicles” does not include street cars operating on rails.
*467Originally, Article I, §102 of the Act of 1929, supra, 75 P.S. §102, defined the term “vehicle” to mean “every device in, upon or by which any person or property is or may be transported . . . upon a public highway, excepting . . . devices . . . used exclusively upon stationary rails or tracks . . . .” In Feldman v. Philadelphia R. T. Co., 106 Pa. Superior Ct. 494, 163 A. 39 (1932), the Superior Court ruled that §1013 (a) of the Act of 1929, supra, 75 P.S. §1013 (a) (formerly 75 P.S. §572), dealing with the right-of-way where two “vehicles” approach an intersection at the same time, did not apply to street cars. Thereafter, the legislature amended said §1013 by the Act of June 29, 1937, P. L. 2329, to read “when two (2) vehicles, or two (2) streetcars, or two (2) trackless trolley omnibuses approach or enter ... an intersection . . . .” (Emphasis supplied). That the legislature deemed it necessary to add the term “streetcars” when it had already included “vehicles” is persuasive that the former is not included in the latter generally. Furthermore, at the same time, the Proviso to §102 of the Act of May 1, 1929, supra, defining “vehicles” was amended to read, “That, for the purpose of Article X of this act, . . . any other device moving upon wheels on a public highway, except a device moving upon wheels upon stationary rails or trades on a public highway, shall be deemed a vehicle.” (Emphasis supplied). Act of June 29, 1937, supra. Thus we see that the legislature fully intended that street cars were not to be regulated under the general provisions of Article X. They are only regulated by those sections (See, e.g., 75 P.S. §1013, supra), which include them specifically. Cf. Dopler v. Pittsburgh Rys. Co., 307 Pa. 113, 160 A. 592 (1932), and Feldman v. Philadelphia R. T. Co., supra. Neither do we subscribe to the position that there is a common law duty requiring a street car to be equipped with a mechanical stop-light device.
*468It is argued that, even if the court erred in that portion of the charge just discussed, it was harmless when the instructions are read and considered as a whole. So reading the charge, we find that in no other instance therein did the court specifically define the duty of the traction company. It is fundamental that the primary duty of a trial judge is clearly and correctly to define the issues to be resolved by the jury: Smith v. Clark, 411 Pa. 142, 190 A. 2d 441 (1963). How could the jury possibly understand the issues to be determined, when the duty of the defendant involved was defined only in an incorrect manner?
Further, under the charge of the court, the jury could find that, even if the street car came to a slow and gradual stop at the intersection, the traction company was still negligent because it violated its statutory duty in not having its mechanical stop-warning signal-lights functioning, and in failing to give such a signal of its intention to stop. What the jury found is, of course, problematical. In determining whether fundamentally erroneous instructions require the grant of a new trial, whether such instructions did or did not bring about the complained of verdict is not the question. If it appears that such instructions might have been responsible for the verdict, a new trial is mandatory: Riesberg v. Pittsburgh & Lake Erie R. R., 407 Pa. 434, 180 A. 2d 575 (1962).
It is also argued that, regardless of the lack of any common law or statutory duty to give a warning of an intended stop through a mechanical signal, the traction company gratuitously assumed and undertook to furnish the members of the public with such a signal, and, having failed to fulfill this obligation on the present occasion, was guilty of negligence. This contention may have merit. However, the case was not tried on this theory, and the court failed to give any instructions in this regard. Such a responsibility, gra*469tuitously undertaken, would entail substantially different obligations than those included in a duty imposed by statute. Further, there was no evidence offered to establish that the alleged failure of the stop-lights to function was due to the negligence of the traction company.
Finally, it is urged that because the traction company-defendant recorded only a general exception to the charge, that it now cannot complain of the error asserted. The error involved was basic and fundamental; therefore, a general exception was sufficient. Smith v. Clark, supra, and Sweeny v. Bonafiglia, 403 Pa. 217, 169 A. 2d 292 (1961).
Judgment reversed, and new trial ordered.