This is an action of tort1 to recover damages for personal injuries, including pain and suffering, alleged by the plaintiff to be the result of the defendant’s negligence as she attempted to board a bus owned and operated by the defendant. The case was originally tried in the Municipal Court of the City of Boston, resulting in a finding for the plaintiff which included damages for pain and suffering. The Appellate Division of the Municipal Court dismissed a report claimed by the defendant. At the defendant’s request, the case was transferred to the Superi- or Court, where it was heard by a judge without a jury on a statement of agreed facts. The judge made findings of fact and rulings of law, and found for the plaintiff in the amount of $1,250, which included damages for pain and suffering. The case is before us on the defendant’s exceptions to the *255denial of its request for rulings that the plaintiff is barred from such recovery by the terms of G. L. c. 231, § 6D ,2
From the statement of agreed facts it appears that the plaintiff was injured when a door closed on her while she was in the act of boarding one of the defendant’s buses. Her injuries “were caused under circumstances that would warrant the Court in finding that said injuries resulted from negligence on the part of the defendant, its servants or agents, and that the plaintiff was in the exercise of due care.” The plaintiff’s injuries consisted of a sprained back and bruises on an arm and a leg. Her medical expense for treatment of those injuries was $50. She incurred no other expense as a result of the accident. Neither the plaintiff nor any member of her household owned a motor vehicle at the time of the accident.
The defendant’s bill of exceptions presents for our consideration a single question of law: Is the plaintiff barred under provisions of G. L. c. 231, § 6D, from recovering damages for pain and suffering because she has neither incurred $500 in medical expenses nor suffered any of the five types of injury specified in the statute? We hold that she is not so barred.
Section 6D was added to the General Laws by St. 1970, c. 670, § 5, as a part of the sweeping reform of motor vehicle insurance legislation commonly known as the “no-fault” law.3 Thus, while it is true, as the defendant points out, *256that § 6D purports to apply generally “[i]n any action of tort brought as a result of bodily injury . .. arising out of the ownership, operation, maintenance or use of a motor vehicle within this commonwealth by the defendant,” this language must be construed in light of the legislative purposes underlying the enactment of the entire no-fault insurance scheme. “Statutes are to be interpreted, not alone according to their simple, literal or strict verbal meaning, but in connection with their development, their progression through the legislative body, the history of the times, prior legislation.... General expressions may be restrained by relevant circumstances showing a legislative intent that they be narrowed and used in a particular sense.” Commonwealth v. Welosky, 276 Mass. 398, 401-402 (1931). The purposes underlying the enactment of the no-fault insurance scheme may be gleaned from an analysis of the operation of St. 1970, c. 670.
On another occasion we have described in detail the workings of the no-fault insurance scheme embodied in St. 1970, c. 670. See Pinnick v. Cleary, 360 Mass. 1 (1971). In that opinion we noted that the “key concept embodied in c. 670 is that of personal injury protection insurance.” Id. at 6. Personal injury protection insurance provides for payments up to $2,000 of medical and other designated expenses by an insurer to the insured (and certain others) regardless of fault in the causation of the accident which resulted in bodily injury. In exchange for the right granted to him to recover directly from his own insurer, the insured loses (to the extent he is eligible for personal injury protection benefits) his traditional common law right to recover in tort even if he is able to prove that the other party to the accident was at fault. Thus, the principal innovation of the no-fault scheme is that owners and operators of motor vehicles insured under that scheme who are injured in accidents are entitled to immediate payment of their actual costs, e.g., medical costs, wages and certain incidental expenses, and in exchange surrender, to a limited extent, of their right to recover damages in tort actions. In addition, in those cases where the accident victim does not *257come within the exceptions specified in § 6D, he surrenders, in exchange for personal injury protection, not only the right to sue for those elements of damage covered by personal injury protection but also the right to sue for pain and suffering. The exemption from tort liability is available to persons who are themselves covered by personal injury protection insurance.
The present case presents the problem of the applicability of the no-fault insurance scheme to a motor vehicle accident in which neither party is covered by personal injury protection benefits. The no-fault provisions (c. 670, §§ 1-4) amended c. 90 of the General Laws. The defendant is exempted from the requirements of c. 90 by § 1A thereof, which provides that motor vehicles owned by street railway companies under public control or by any political subdivision of the Commonwealth are exempt from the insurance requirements of the chapter.4 The defendant thus has no personal injury protection coverage.5 The plaintiff has no such coverage because at the time of the accident neither she nor any member of her household owned a motor vehicle. In addition, while the statute permits pedestrians and passengers to recover personal injury protection benefits through the insurance covering the motor vehicle by which or in which they are injured, this provision does not help the plaintiff since the defendant has no such coverage. Finally, while the statute requires the creation of an “assigned claims plan” in order to provide personal injury protection benefits to Massachusetts residents when no other coverage is available (c. 90, § 34N, inserted by St. 1970, c. 670, § 4), the regulations of the Commissioner of Insurance apparently permit recovery under that plan only when the injury is caused by an uninsured Massachusetts motor vehicle, which is required to be insured, a “hit- *258and-run” accident, or an out-of-State car.6 Since the defendant does not fit in any of these categories, the plaintiff is unable to recover under the assigned claims plan.
The mere fact that the defendant does not have personal injury protection coverage does not exempt it from tort liability. There can be no question, therefore, that the plaintiff may sue the defendant for damages. The defendant argues, however, that the plaintiff’s right of action does not include the possibility of recovery for pain and suffering. In other words, the defendant would have us extend to it the benefits of the exemption from liability for pain and suffering even though it does not bear the burden of providing protection afforded under the compulsory insurance statute. We do not believe that the Legislature intended so to protect the defendant by barring recovery for pain and suffering by persons, such as the plaintiff, who do not receive the compensating benefit of personal injury protection.
In our discussion of the no-fault law in Pinnick v. Cleary, 360 Mass. 1, 8 (1971), we noted that “|b]ecause the exemption of the tortfeasor is exactly matched to the availability of personal injury protection benefits to the plaintiff, the plaintiff loses nothing by it.” If we were to adopt the defendant’s construction of § 6D, the plaintiff in this case would lose her right to recover for pain and suffering even though she receives no personal injury protection benefits and must sue even to recover her out-of-pocket medical expenses. The more logical interpretation of the legislative intent is that this defendant and this plaintiff are beyond the scope not only of the personal injury protection coverage but also of every aspect of the *259no-fault insurance scheme.7 As we noted in Pinnick v. Cleary, a principal purpose behind the no-fault legislation was the reduction of liability insurance premium rates for Massachusetts motor vehicle owners. Id. at 20,8 Since the defendant is a self-insurer, its experience has no effect whatsoever on liability insurance rates, and the extension of the pain and suffering exemption of § 6D to the defendant would in no way further the legislative purpose of reducing insurance premiums. Thus, it is logical to conclude that the Legislature intended that in the circumstances of the present case the plaintiffs right of recovery against the defendant should remain unaffected by the provisions of St. 1970, c. 670, including the provision which creates the pain and suffering exemption.
Although we are convinced that this conclusion is the correct one purely as a matter of statutory interpretation, we also note that any interpretation which would bar this plaintiff from recovering for pain and suffering would raise doubts as to the constitutionality of at least one aspect of the no-fault scheme. Although in Pinnick v. Cleary we concluded that the no-fault scheme in its principal aspects is constitutional, we expressly declined to consider whether “the extension of personal injury protection benefits in lieu of damages to the ‘pure pedestrian,’ who neither owns a car nor is a member of a household which owns one, is a deprivation to him of due process.” Id. at 27. The present case presents the even more serious question of the possible denial of due process rights to a “pure pedestrian,” i.e., the *260plaintiff, who if denied damages would also not receive in return the benefits of personal injury protection. We need not decide this question now, since the statute may rationally be interpreted so as to avoid raising the constitutional issue. “We must construe the statute, ‘if fairly possible, so as to avoid not only the conclusion that it is unconstitutional but also grave doubts upon that score.’ ” Board of Appeals of Hanover v. Housing Appeals Comm. in the Dept. of Community Affairs, 363 Mass. 339, 364 (1973), quoting from United States v. Jin Fuey Moy, 241 U. S. 394, 401 (1916).
In conclusion, we wish to emphasize that this decision is restricted to the facts of this case. All that we have decided today is that a plaintiff who has no recourse to personal injury protection benefits is not barred by G. L. c. 231, § 6D, from recovering damages for pain and suffering when the uninsured defendant is expressly exempted from the no-fault scheme by c. 90, § 1A. Whether such a defendant is protected by G. L. c. 231, § 6D, in other respects is an issue we do not reach on this record.9
Exceptions overruled.