The action of the Commissioner in revoking the petitioner’s operator’s license was mandated by the statute, upon the receipt by the Commissioner of certificates of convic*387tian, showing that the petitioner had been convicted of three speeding offenses, committed within a period of 18 months (Vehicle and Traffic Law, § 71, subd. 2, par. [c]). The petitioner seeks to attack the third conviction upon the ground that it was based upon a plea of guilty by mail in the Bronx Traffic Court, which he claims the court was not authorized to accept under section 335 of the Code of Criminal Procedure. It is firmly settled that a collateral attack upon a judgment of conviction may not be entertained in an article 78 proceeding brought to review the Commissioner’s order of revocation. Under the statute, the Commissioner has neither the power nor the duty to go behind the conviction certified to him and to inquire into, or to pass upon, the validity of the conviction (Matter of Christoff v. Kelly, 8 A D 2d 687; Matter of Banks v. Kelly, 6 A D 2d 512; La Victoire v. Kelly, 5 A D 2d 548; Matter of Gross v. Macduff, 284 App. Div. 786).
If the petitioner wished to challenge the validity of the conviction, his remedy was to bring a proceeding in the court in which the conviction had been had. In his petition, the petitioner asked, as alternative relief, that he be given “ an opportunity [to] forthwith commence a coram nobis proceeding in Bronx City [sic] Traffic Court, if necessary ” but, so far as we have been advised, no such proceeding has been brought.
It is at least doubtful whether a direct attack upon the conviction in the Bronx Traffic Court would be successful. In view of the fact that there is no statutory provision applicable to New York City for pleas of guilty by mail with respect to speeding charges, although there is such a provision with respect to other traffic violations (N. Y. City Grim. Cts. Act, § 127 and proclamations thereunder), we may assume that the acceptance of petitioner’s plea of guilty by mail was not authorized by statute (Code Grim. Pro., § 335, subd. 1). (But, see, Code Crim. Pro., §§ 297, 356, 424; General Municipal Law, § 371.) But even though the plea was not authorized by any statute, it may well be found that the petitioner had waived his right to be personally present, by pleading guilty by mail for his own convenience, and the conviction may accordingly be permitted to stand. This was in substance the holding in Matter of Gross v. Macduff (284 App. Div. 786, supra) decided in 1954. Subsequently chapter 78 of the Laws of 1955 was enacted, adding-subdivision 2 to section 335 of the Code of Criminal Procedure, expressly authorizing pleas of guilty by mail with respect to certain traffic infractions. The amendment excluded New York City and Nassau County from its scope but this exclusion did not have the effect of prohibiting the courts in those parts of *388the State from upholding a conviction upon the ground of waiver under the doctrine of the Gross case. The purpose of the exclusionary clause, as indicated in the memorandum by the cosponsor of the amendment, was to leave undisturbed the ‘1 provisions now regulating traffic violations in those municipalities.” (Memorandum by the Association of Towns, Governor’s Bill Jacket for L. 1955, ch. 78.) It is worth noting that this memorandum, as well as the memorandum submitted by the principal sponsor of the amendment, the Joint Legislative Committee on Traffic Violations (N. T. Legis. Doc., 1955, Mo. 68, p. 40), cited the doctrine of the Gross case (supra) with approval. It is thus at least arguable that, even in a case in which a plea of guilty by mail is not authorized by subdivision 2 of section 335, the defendant may be held to have voluntarily waived the requirement of subdivision 1 by his plea, and the conviction may accordingly be allowed to stand. (See, also, People v. La Barbera, 274 N. Y. 339; People ex rel. Walsh v. Warden, 176 Misc. 627.) In this situation, the Commissioner of Motor Vehicles was certainly not called upon to speculate as to whether the petitioner’s conviction in the Bronx Traffic Court would or would not stand if it were attacked in that court.
As to the other points raised by the petitioner, it is enough to note that the renewal of his operator’s license, during the pendency of a stay in the review proceeding, did not affect the validity or effectiveness of the Commissioner’s order of revocation (Matter of Colonial Liq. Distrs. v. O’Connell, 295 N. Y. 129) and that section 335-a of the Code of Criminal Procedure had been fully complied with by the printing of the statutory warning-on the traffic summons.
The order appealed from should be reversed and the proceeding dismissed.