This is an appeal from an order granting a motion for judgment on the pleadings. The issue is when the two year limitations period starts to run in a case arising from a motor vehicle accident where the right to bring a tort action is limited by the Pennsylvania No-fault Motor Vehicle Insurance Act, Act of July 19, 1974, P.L. 489, No. 176, 40 P.S. § 1009.101 et seq. In Donnelly v. DeBourke, 280 Pa.Superior Ct. 486, 421 A.2d 826 (1980), we held that the limitations period starts to run on the date of the accident. However, it does not appear that the court in Donnelly was asked to consider the significance of Singer v. Sheppard, 464 Pa. 387, 346 A.2d 897 (1975). We therefore ordered reargument of *209this case before the court en banc in order to reconsider our decision in Donnelly in light of Singer. We now overrule Donnelly and hold that the two year limitations period does not start to run until the claimant knows or in the exercise of reasonable diligence should have known that one of the thresholds specified in section 301(a) of the No-fault Act had been reached.
The facts of this case are quite simple. Appellant was injured on February 3, 1977, when the automobile she was driving was struck by an automobile driven by appellee. Appellant did not file her complaint until more than two years later, on April 12, 1979. However, in her complaint she detailed the course of treatment for the injuries she suffered in the accident, alleging that it was not until December 2, 1978, that she first believed that her medical expenses would exceed $750, and not until sometime after December 17, 1978, when she was admitted to a hospital for surgery, that her expenses actually did exceed $750. Appellee filed an answer to the complaint with new matter alleging that appellant’s claim was barred by the statute of limitations, and then filed a motion for judgment on the pleadings, which by order of April 21, 1980, the lower court granted. This appeal followed.
At this stage we must take appellant’s allegations as true. Engel v. Parkway Company, 439 Pa. 559, 266 A.2d 685 (1970). Accordingly, the case may be summarized by saying that while appellant’s complaint was filed more than two years after the accident, it was filed less than two years, specifically, only four months, after appellant met a no-fault threshold allowing tort recovery.
In Singer v. Sheppard, supra, the Supreme Court held that the No-fault Act does not violate Article 1, Section 11, and Article 3, Section 18, of the Constitution of Pennsylvania because, instead of limiting the damages recoverable in a tort action, the Act abolishes the right to recover any damages, unless the claim falls within one of the exceptions contained in section 301(a). Id. 464 Pa. at 397, 346 A.2d at 902-03. The Court interpreted the Constitution as requiring *210only that when a cause of action exists, access to the courts may not be restricted nor damages limited. The Constitution, said the Court, does not deprive the General Assembly of the power to abolish a cause of action. Thus, when we are asked to decide when the statute of limitations starts to run, we must give an answer consistent with the Court’s interpretation of the No-fault Act as not a limitation on a remedy but as an abolition of a cause of action.1 Upon reflection, it is clear that the holding in Donnelly v. De-*211Bourke, supra, is not consistent with Singer. To say, as Donnelly did, that the statute of limitations starts to run from the date of the accident, even when none of the No-fault Act’s thresholds has been reached, is to say that the statute starts to run from a date on which, and even though, the cause of action did not exist.
This point may perhaps be made clearer by imagining a dialogue between a trial judge required to follow the holding of Donnelly and a disappointed claimant. Suppose the accident was on January 1, 1978, but the $750 threshold was not reached until February 1, 1980. Judge: “Your claim is barred because the statute of limitations started to run on January 1, 1978.” Claimant: “But under Singer I didn’t have any cause of action on January 1, 1978. In fact, I didn’t get a cause of action until February 1, 1980. By then, according to you, the statute had already run.” Judge: “That’s true, and it’s too bad. What you should have done is, before the statute had run, file a claim saying that although you had no cause of action, because the $750 threshold hadn’t been reached, maybe you would have one, because maybe the threshold would be reached. That way you would have protected yourself.” Although stated in colloquial language, this dialogue fairly summarizes the holding in Donnelly.
This holding is unacceptable for two reasons: First, it cannot be supposed that in enacting the No-fault Act, the General Assembly intended such a result. In this regard it may be noted that although Donnelly does discuss policy considerations favoring its result, it cites no provisions of the Act in support of its conclusions.2 Second, the result is *212unjust and unnecessary. Why should such a claimant be barred? What sense does it make to tell claimants—i. e., tell their lawyers—that to protect themselves, they must file fictitious, precautionary, claims? How can such claims be reconciled with Pennsylvania’s system of fact pleading—not to mention, with simple honesty?
It is true that the present case is not quite so dramatic as the case just supposed. For here the threshold was reached twenty-two months after the accident, instead of twenty-five. In other words, here we could say to appellant: “You *213knew two months before the statute ran that you had a cause of action. It was therefore up to you to file your claim within those two months.” This answer, however, will not withstand examination. For the fact remains that it cannot be supposed that the General Assembly intended thus to constrict a claimant’s right to assert a cause of action. Suppose the threshold is reached one month before the statute—according to Donnelly —runs. Did the General Assembly intend that unless the claimant asserts the cause of action within that one month, the cause is barred? Suppose the threshold is reached two weeks before the statute—according to Donnelly—runs. One week. One day.
Thus, in every case, Donnelly’s answer to the claimant is the same: “Your cause of action is barred unless you assert it within two years of the date of the accident, and this is so no matter when you reach the threshold, whether two months before the two year period expires, or one month, two weeks, one week, one day, or even afterwards.”
Given that when reexamined in the light of Singer, Donnelly is not acceptable, the question becomes: “How, then, should the limitations period be computed?” We believe, and now hold, that the limitations period does not start to run until the claimant knows or in the exercise of reasonable diligence should have known that one of the section 301(a) thresholds had been reached, in other words, until the claimant has a cause of action that can be pleaded, consistent with the fact-pleading requirements of Pa.R.C.P. 1019(a).3 Donnelly v. DeBourke, supra is overruled.4
*214We recognize that this result is not entirely satisfactory, for cases may occur where the threshold is reached only after many years. Such cases, however, will be rare, and in any event, the difficulty they present may readily be avoided by the General Assembly. For example, the General Assembly could enact a statute of repose similar to the Act of July 9, 1976, P.L. 142, § 2, as amended, 42 Pa.C.S.A. § 5536, which provides that after 12 years, an action based on a defect in the design or construction of any improvement to real property is barred, regardless of when the defect was discovered or discoverable or the injury occurred. In this regard, it should be noted that neither a statute of repose nor a limitations period triggered by an event subsequent to the date of the accident is foreign to the No-fault Act as it now exists. Section 106(c)(1) provides, in part: *215The four year period is a statute of repose; the two-year period is triggered by an event subsequent to the accident. Although by its very nature a limitations period triggered by an event subsequent to the accident is less certain than one triggered by the accident itself, this fact does not present any problem that has not been overcome in other cases in the development of the discovery rule. See e. g., Ayers v. Morgan, 397 Pa. 282, 154 A.2d 788 (1959); Anthony v. Koppers Company, Inc., 284 Pa.Superior Ct. 81, 425 A.2d 428 (1980). Finally, the No-fault threshold that has attracted the most attention—the requirement of $750 in medical expenses—is itself stated in terms of “the reasonable value of reasonable and necessary medical and dental services, ...” 40 P.S. § 1009.301(a)(5)(B). There is no provision that for the threshold to be met, the medical and dental services must have been billed or paid for. Thus a claimant may not defer the date the limitations period starts to run by, for example, being slow in paying for medical treatment.
*214If no-fault benefits have not been paid for loss arising otherwise than from death, an action therefor may be commenced not later than two years after the victim suffers the loss and either knows, or in the exercise of reasonable diligence should have known, that the loss was caused by the accident, or not later than four years after the accident, whichever is earlier.
*215The order of the lower court granting appellee’s motion for judgment on the pleadings will therefore be reversed and the case remanded for further proceedings. If it should appear, either on motion for summary judgment or at trial, that appellant did not file her action within two years after she knew or in the exercise of reasonable diligence should have known that a no-fault threshold had been reached, the action should be held barred. Otherwise, it should be held to lie.
The order of the lower court is reversed and the case remanded for further proceedings consistent with this opinion.
JOHNSON, J., files a dissenting opinion, in which CER-CONE, P. J., joins.. The dissent argues that we should give no weight to Singer because no Justice joined the lead opinion, written by then Chief Justice JONES. Dissenting op. at 15. However, the concurring opinions, written by Justice ROBERTS, joined by Justice POMEROY, and by Justice NIX, make clear that they too, like the Chief Justice, regarded the No-fault Act as an exercise of the Legislature’s power to create and abolish causes of action. Justice ROBERTS wrote:
[Article III, section 18 of the Pennsylvania Constitution] does not limit the power of the Legislature to create or abolish causes of action; ...
Section 301(a) of the No-fault Act does not place a maximum dollar limitation on the amount of damages that are otherwise recoverable by a person injured in a motor vehicle accident. Rather, it specifies in what circumstances a person has a cause of action for injuries received in a motor vehicle accident . ..
Singer v. Sheppard, supra 464 Pa. at 415-16, 346 A.2d at 911-12 (ROBERTS, J., concurring) (footnote omitted; emphasis added). Similarly, Justice NIX wrote:
The law is clear that the General Assembly has the power to abolish common law causes of action .... [T]he legislature recognized the desirability of eliminating the common law cause of action for pain and suffering from injuries resulting from automobile accidents.
Id., 464 Pa. at 418, 346 A.2d at 912-913 (NIX, J., concurring) (citation omitted; emphasis added).
If there could otherwise be any doubt that the three opinions upholding the constitutionality of the No-fault Act all agreed that the Act was constitutional only because it abolished a cause of action rather than limiting damages, it is dispelled by Justice MANDERINO’s dissenting opinion:
The opinion of Mr. Chief Justice JONES and the concurring opinions agree that, without the people’s approval, the legislature cannot put a maximum dollar amount on damages recoverable by citizens for injuries. Yet, it is contended that this proposition does not prevent the abolition of a cause of action.
Id., 464 Pa. at 420, 346 A.2d at 914 (MANDERINO, J., dissenting). When four of the seven Justices write or join opinions that agree on a proposition of law, that proposition does carry the authority of the Court, and we are bound by it.
. Donnelly does cite cases from other states holding that the statute of limitations runs from the date of the accident. Carter v. Cross, 373 So.2d 81 (Fla.Dist.Ct.App.1979); Key v. Clegg, 4 Kan.App.2d 267, 604 P.2d 1212 (1980); Dinesen v. Towle, 3 Kan.App.2d 505, 597 P.2d 264 (1979); Cappadona v. Eckelmann, 159 N.J.Super. 352, 388 A.2d 239 (App.Div.1978). An examination of these cases will disclose, however, that in none of them is the no-fault act in question analyzed in the way in which our act was analyzed in Singer. Instead, in all of these cases the no-fault act is analyzed as providing limitations on recovery and qualified immunities for liability, not as *212abolishing a cause of action. This difference in analysis is illustrated most vividly by Cappadona v. Eckelmann, supra, which is also the case that Donnelly quotes at some length. According to Cappadona, “The tort exemption provision, N.J.S.A. 39:6A-8, is no more than an affirmative defense to be pleaded and proved by the party favored by it.” 159 N.J.Super. at 357, 388 A.2d at 242. The court specifically found that the New Jersey no-fault act provided exemption from liability, not from suit, and that failure to meet the no-fault threshold was therefore not a jurisdictional defect. Thus, if the exemption from liability is not pleaded by the defendant, a tort suit following an automobile accident may lead to a valid judgment even if the threshold has not in fact been met. The court also pointed out that because the threshold in New Jersey is so low—only $200—and because it is only necessary that it be met by the time of trial, it will be only a very rare case where the threshold has not been met in two years plus the time it takes for the case to come to trial, but is met later.
So far as Pennsylvania cases before Donnelly are concerned, the courts of common pleas have disagreed on whether it is necessary to meet a no-fault threshold before filing suit. Compare:
No useful purpose would be served by requiring a plaintiff actually to have incurred $750 in medical expenses before filing suit if it can be fairly alleged that the medical expenses are reasonably expected to be in excess of the threshold amount. A contrary ruling would not only raise problems with respect to the statute of limitations but might encourage early, excessive or unnecessary treatment. Mabey v. Michkens, 7 D. & C.3d 792, 1 Phila. 355, 357-58 (1978).
Accord, O’Sullivan v. Ruszecki 2 D. & C.3d 276 (Allegheny Co. 1977); Theal v. Confer, 7 D. & C.3d 614 (Perry Co. 1978). With:
[W]e find that the legislative debates leading up to the passage of the No-Fault Act fully considered the $750 threshold criterion [footnote omitted], and intended such to be met before the institution of suit.
Gleeson v. Belkin, 9 D. & C.3d 499 (Phila.Co.1980) (omitted footnote discusses examples of legislative history.)
Accord, Kubushefski v. Kleinot, 8 D. & C.3d 599 (Phila.Co.1979). However, all of the cases appear to agree that a claimant must in some way plead exemption from the No-Fault Act’s abolition of tort liability. This requirement is consistent with Singer but in sharp contrast to New Jersey practice as explained in Cappadona.
. The dissent expresses concern that to hold that a cause of action does not accrue until a No-fault threshold has been met may mean that there may be no recovery for non-economic detriment incurred prior to that point. Dissenting op. at 15. As that question is not before us, we need not decide it today. However, even if the dissent is right, it is far from clear that such a result would be contrary to the intent of the No-fault Act. If a No-fault threshold is never reached, damages for non-economic detriment can never be recovered. In the case of a major accident a No-fault threshold will be met almost immediately, possibly even before the victim reaches the hospital. It is difficult to imagine a case where there would be great pain and suffering before a threshold was met but not afterwards; in *214any event, the calculation of damages for pain and suffering is, at best, not very precise.
. See note 4 on page 214.
*2144. The dissent suggests that we should attach some weight to the fact that Donnelly “has withstood a Petition for Allowance of Appeal.” Dissenting op. at 16. However, an order denying a petition for allowance of appeal does not constitute or imply an endorsement by the Supreme Court of the position taken by the Superior Court or the Commonwealth Court; it is instead a discretionary order, and of no precedential value. Pa.R.A.P. 1114 provides that “review of a final order of the Superior Court or the Commonwealth Court is not a matter of right, but of sound judicial discretion, and an appeal will be allowed only when there are special and important reasons therefor.” The Note to the Rule states that the Rule is “[bjased on U.S. Supreme Court rule 19 [now renumbered Rule 17],” which states the considerations that govern discretionary review by the United States Supreme Court on writ of certiorari. It is settled that an order entered pursuant to Rule 19 denying a petition for writ of certiorari is of no precedential value. Maryland v. Baltimore Radio Show, 338 U.S. 912, 70 S.Ct. 252, 94 L.Ed. 562 (1950).