WILKINS, J.

For the first time in more than a decade, this court deals with the question whether a criminal complaint charging motor vehicle violations should be dismissed on the claimed ground that a police officer did not seasonably issue a citation to the defendant as required by G.L.c. 90C, § 2 (1992 ed.). The issue, which divided a panel of the Appeals Court ( Commonwealth v. Cameron, 34 Mass. App. Ct. 44), is here on further appellate review. Because of the seriousness of the injury sustained by a teenage boy whom the defendant's vehicle struck and because the purposes of § 2 would not be thwarted if the complaint were not dismissed, the principles expressed in Commonwealth v. Babb, 389 Mass. 275 (1983), control, and we vacate the order of the District Court dismissing the complaint.

We summarize the essential facts which are more fully set forth in the opinion of the Appeals Court. Commonwealth v. Cameron, supra at 45-46. On April 27, 1988, Officer Soares of the Dartmouth police arrived at the scene of an accident in which a motor vehicle operated by the defendant had struck a teenage boy on a bicycle. The vehicle was damaged, and the boy, apparently seriously injured, was lying on the ground. The defendant, who had run behind a house, seemed to be in shock but gave his license and registration to the officer. After the defendant had left the scene with a friend, Soares and another officer worked at the accident scene for the next two hours. Soares learned that evening that the boy's life was in danger. The next day, after further investigation, Soares concluded that the defendant had been speeding and had crossed the solid double line in the road before striking the boy. No further investigation was needed before issuing a citation to the defendant. On April 29 and 30, Soares was not on duty. On May 1, he learned from the boy's mother that the boy's condition had stabilized. He then informed the defendant that a citation would be issued for operating to endanger, speeding, and failure to stay within marked lanes, and such a citation was issued that day.

Section 2 provides that a citation should be given to the violator at the time and place of the violation and that failure to do so "shall constitute a defense in any court proceeding for such violation." There are exceptions, such as when there is a reasonable need for additional time to determine the nature of the violation and "where the court finds that a circumstance, not inconsistent with the purpose of this section to create a uniform, simplified and non-criminal method for disposing of automobile law violations, justifies the failure." G.L.c. 90C, § 2.

One of the purposes of § 2, commonly called the "no-fix" law, "is to afford prompt and definite notice of the nature of the alleged offense to the putative violator." Commonwealth v. Pappas, 384 Mass. 428, 431 (1981). The objective is "to prevent a situation in which a person cannot establish a defence due to his being charged with a violation long after it occurs." Commonwealth v. Gorman, 356 Mass. 355, 357-358 (1969). The judge who allowed the motion to dismiss seems to have relied in part on the defendant's state of shock to conclude that the defendant had no notice of the seriousness of the incident. In affirming the motion judge, however, the Appeals Court rightly did not depend on the absence of notice. Justice Dreben's dissent points out the reasons why the notice purposes of § 2 were fully satisfied in the circumstances. See Commonwealth v. Cameron, supra at 48-49 (Dreben, J., dissenting), citing Commonwealth v. Pappas, supra at 431-432. It is not reasonable to conclude that the defendant was not aware of the seriousness of the accident.

The more significant issue, and the one that divided the Appeals Court, concerns the question whether any circumstance, consistent with the purpose of § 2, justified the failure to deliver a citation until four days after the accident. The Appeals Court opinion rejected Officer Soares's mistaken belief that he had to discover whether the boy died before he could issue any citation and also rejected as adequate justification the two days' delay while Soares was off-duty. Id. at 46-47. It concluded that the Commonwealth had presented no justification for the failure to deliver or mail a citation the day after the accident. Id. at 47. The Appeals Court opinion does not cite this court's opinion in Commonwealth v. Babb, 389 Mass. 275 (1983), on which Justice Dreben relied in her dissent. Commonwealth v. Cameron, supra at 48-49 (Dreben, J., dissenting).

The Babb case stands for the proposition that, assuming the notice and abuse prevention purposes of § 2 are met, the apparent seriousness of the accident itself may justify a refusal to dismiss a complaint when an officer failed to issue a citation seasonably. In our Babb opinion, we said that "this court and the Appeals Court on numerous occasions have held that failure to comply with the statute is not fatal where the purposes of the statute have not been frustrated." Commonwealth v. Babb, supra at 283. "So also the cases make clear that the very seriousness of particular charges tends to minimize the importance of absolute observance of the procedures because, again, `fix' is virtually excluded, and notice is implicit." Id., quoting Commonwealth v. Perry, 15 Mass. App. Ct. 281, 284 (1983). Indeed, the 1986 amendment of § 2 (St. 1986, c. 620, § 18, creating an exception for motor vehicle violation causing death) shows that, when the most serious of personal injuries is involved, the purposes of § 2 are made unimportant as against the public interest in the prosecution of such violators.

Because there was an obvious, life-threatening injury in this case and no purpose of § 2 is being thwarted, and because the police were not seriously deficient or negligent in their handling of the matter, we conclude that there was justification for excusing the three-day delay in issuing the citation. We thus disagree with an analysis of § 2 that measures "justification" in this case simply in terms of the inadequacy of the explanation that Soares took two days off and did not understand that an effective citation for motor vehicle homicide could be issued at any time if the injured boy should die. In deciding this case, we look more broadly at the purposes of § 2. See Commonwealth v. Babb, supra at 283-284; Commonwealth v. Gorman, 356 Mass. 355, 357-358 (1969) (procedures of § 2 inapplicable when there is an arrest, although § 2 does not say so). The delay of three days in issuing a citation in the circumstances of this case does not justify the dismissal of the complaint. A finding is required as a matter of law that the officer was justified in issuing the citation despite the delay. The order of the District Court dismissing the complaint is vacated, and an order shall be entered denying the motion to dismiss the complaint.

So ordered.