dissenting.
There is much in the majority opinion with which I agree. I have no difficulty, for example, with the proposition that states are entitled to considerable deference in their legitimate and nondiseriminatory attempts to promote safety on the highways. Similarly, I too believe that the judicial role in “dormant” commerce clause cases of this sort should be a relatively limited one, not only because courts generally are ill-equipped to evaluate the wisdom of legislation intended to promote safety, but also because Congress always retains the ability, through the exercise of its plenary powers, to invalidate any state regulation that it deems to be an intrusion on the commercial interests of the nation. Nonetheless, I do not join my colleagues in upholding the Pennsylvania truck inspection statute challenged here. My divergence from the majority can be briefly stated: I believe that the balancing test is the better of the two standards for resolving dormant commerce clause disputes and that, when this test is applied, the balance weighs against the Commonwealth’s legislative effort.
I
As the majority opinion aptly demonstrates, the Supreme Court has not yet arrived at an agreed-upon standard for determining the constitutionality of a state’s safety-related legislation that allegedly interferes with interstate commerce. In essence, because a majority of the Justices has been unable to endorse either of the two competing tests,1 “this court must *802choose whether to apply the balancing approach used by Justice Powell or the highly deferential standard espoused by Justice Rehnquist.” Majority Opinion at 794.
For three reasons, my colleagues endorse the deferential standard of review; that is, they accord the Pennsylvania inspection statute a “strong presumption of validity” and ultimately conclude that the plaintiffs here were unable to demonstrate that the safety benefits intended to be realized by the measure were “slight,” “problematical,” or “illusory.” Id. at 795. First, the majority notes that five Justices appear to have rejected the legitimacy of balancing competing interests when safety regulations are involved. As previously discussed, however, see note 1 supra, I do not believe it can be said that either of the two competing approaches has received the imprimatur of a Supreme Court majority. Second, my colleagues contend that, as long as the rational relation standard of review is considered adequate in assessing the constitutionality of various state commercial statutes and regulations, a “similarly deferential standard” is in order when reviewing highway safety legislation of a “peculiarly local nature.” I of course cannot quarrel with the notion that the “bite” of judicial
review should be at a minimum in those situations in which a state draws distinctions among its citizens that neither impinge upon a fundamental right nor discriminate against a suspect class. See Murillo v. Bambrick, 681 F.2d 898 (3d Cir. 1982). I am not convinced, however, that the equal protection analogy applies with respect to commerce clause questions: after all, when a state acts to burden interstate commerce, whatever its motivations, it affects the activities and interests not only of its own citizens, but also those of unrepresented outsiders (such as the truckers complaining in the matter at bar). It is not improbable, therefore, that an economic policy that might appear rational from the perspective of the enacting state would be antithetical to the commercial interests of the nation as a whole.2 Third and finally, the majority suggests that “the halls of the state legislature are a more appropriate forum for resolution of [highway safety] disputes than are the walls of a judge’s chambers.” At 795. I am not persuaded, however, that absolute judicial reticence is appropriate when reviewing the actions of state legislatures, whose safety-related judgments, essentially attuned to local considerations, do not necessarily reflect an *803adequate comprehension or consideration of the burdens placed on interstate intercourse.3
In my view, the better analytical approach to dormant commerce clause matters is the “sensitive” balancing advocated by the plurality in Kassel v. Consolidated Freightways Corp., 450 U.S. 662, 101 S.Ct. 1309, 67 L.Ed.2d 580 (1981).4 Under this standard, “the incantation of a purpose to promote the public health or safety does not insulate a state law from Commerce Clause attack.” Id. 450 U.S. at 670, 101 S.Ct. at 1316. Rather, a reviewing court is obligated to engage in a careful “ ‘weighing of the asserted safety purpose against the degree of interference with interstate commerce.’ ” Id. (quoting Raymond Motor Transportation, Inc. v. Rice, 434 U.S. 429, 443, 98 S.Ct. 787, 795, 54 L.Ed.2d 664 (1978)). Ordinarily, because of their “strong presumption of validity,” Bibb v. Navajo Freight Lines, Inc., 359 U.S. 520, 524, 79 S.Ct. 962, 964, 3 L.Ed.2d 1003 (1959), state and local regulations intended to advance highway safety will withstand constitutional attack. In some — admittedly rare — cases, however, state restrictions may “further the [safety] purpose so marginally, and interfere with commerce so substantially, as to be invalid under the Commerce Clause.” Kassel, 450 U.S. at 670, 101 S.Ct. at 1316.
The reason for favoring the balancing over the deferential test derives from a recognition that situations may arise where enormous burdens are placed on interstate commerce by nondiscriminatory, non-illusory state safety statutes. In these instances, I believe it unwise and imprudent for a federal court to ignore significant and size-able infringements on national commercial interests solely because some, arguably marginal, local safety objective is served. A few examples may suffice. It doubtless would increase highway safety were a state to mandate that all trucks traveling on its roads be covered with luminous paint, be driven at speeds not to exceed thirty five miles per hour, or be inspected weekly. Under the deferential standard of commerce clause review, having made such a determination, a court’s inquiry must end. It is troubling, however, to accept an analysis that excludes from the decisionmaking calculus the tremendous burdens placed on interstate commerce by each of these (rath*804er fanciful) regulations. Indeed, it is difficult to reconcile such an approach with the long-standing notion that the commerce clause exists, in part, to “prevent[] the States from erecting barriers to the free flow of interstate commerce,” Raymond Motor, supra, 434 U.S. at 440, 98 S.Ct. at 793; see Great Atlantic and Pacific Tea Co. v. Cottrell, 424 U.S. 366, 370-71, 96 S.Ct. 923, 927, 47 L.Ed.2d 55 (1976) (citing cases).
In my opinion, the better judicial practice would take into account costs as well as benefits; it would balance local safety objectives against “the national interest in keeping interstate commerce free from interferences which seriously impede it,” Bibb, supra, 359 U.S. at 524, 79 S.Ct. at 964. See The Supreme Court, 1980 Term, supra note 2, at 102 (recommending that the Supreme Court “candidly balanc[e] the interests involved” in dormant commerce clause cases, because “[although a state’s interest in safety may be legitimate, it may still be unreasonable in light of the burdens . . . imposed on interstate commerce”). Such a stance, it seems to me, comes closest to realizing the Framers’ conviction that “in order to succeed, the new Union would have to avoid the tendencies toward economic Balkanization that had plagued relations among the Colonies and later among the States under the Articles of Confederation.” Hughes v. Oklahoma, 441 U.S. 322, 325-26, 99 S.Ct. 1727, 1730-31, 60 L.Ed.2d 250 (1979); see H. P. Hood & Sons, Inc. v. Du Mond, 336 U.S. 525, 533-34, 69 S.Ct. 657, 662-63, 93 L.Ed. 865 (1949).
II
If, then, a balancing standard is to be applied in the matter at bar, I believe that the Pennsylvania statute challenged here cannot survive constitutional scrutiny. The most striking fact that emerges from the testimony and evidence introduced at trial, in my view, is the overwhelming burden placed on interstate commerce by the Commonwealth’s highway regulation. The district court found that, once the inspection requirement took effect, nearly one million out-of-state vehicles, currently not required to be examined by any state, would be affected.5 American Trucking Associations, Inc. v. Larson, 515 F.Supp. 1327, 1330 (M.D.Pa.1981). Assuming, of course, that their owners chose not to avoid Pennsylvania highways entirely,6 these tractors and trailers would have to be inspected, either in the Commonwealth or elsewhere, in order to be operated in accordance with the law on Pennsylvania’s roads.
The inspections themselves, according to the district court, involve “considerable costs and delays,” id. at 1332 — a proposition with which the Commonwealth does not take issue. For example, the district court found that: “[t]he cost for each inspection of a semitrailer at an official inspection station ranges from $12.00 to $18.00”; “[tjhere also would be further costs connected with drivers’ salaries and additional fuel consumption while taking motor carrier vehicles to an inspection station, waiting during the inspection, and returning the vehicle to the owners’ place of business or back to its intended course of travel”; “[t]he average tractor inspection takes at least ninety minutes and the average trailer or semitrailer inspection about thirty minutes”; “perishable items may be damaged because of the delay required by inspection”; inspection stations are not open at night, when much of the interstate truck traffic occurs. The district court also cred*805ited testimony that one, presumably representative, trucking company (Coastal Tank Lines) would be forced to expend more than $150,000 annually in order to comply with the Pennsylvania statute. Id. at 1332-34.7 It is difficult to quarrel with the conclusions drawn by the district court from the record compiled in this case: that the truckers “ ‘produced uncontradicted evidence showing that their operations [would be] disrupted, their costs [would be] raised, and their service .. . slowed’ if the inspection statute is permitted to go into effect,” and that therefore “the Pennsylvania law places substantial burdens on interstate commerce.” Id. at 1332, 1340 (quoting Raymond Motor, supra, 434 U.S. at 438, 98 S.Ct. at 792).
Although the question is close, I would not disturb the district court’s finding that Pennsylvania failed to demonstrate that its inspection program would bring about anything other than “insubstantial, slight, and problematical benefits,” American Trucking, supra, 515 F.Supp. at 1338. To be sure, it borders on the intuitive that, at least in some cases, careful inspection of a vehicle may reveal a mechanical defect which, had it gone undetected, might have resulted in an accident. But, as the district court found, interstate trucks already are subject to rigorous inspection requirements: all interstate carriers must satisfy the directives relating to inspection, maintenance, and repair of their vehicles set forth by the federal Bureau of Motor Carrier Safety (BMCS), see 49 C.F.R. § 396 (1981)8 Indeed, trial testimony established that “motor carriers typically inspect their vehicles from 4 to 12 times per year depending upon vehicle usage, region of the country, and other factors,” 515 F.Supp. at 1332. The appropriate inquiry, therefore, at least under the balancing test, is not whether annual or semiannual examinations of otherwise-uninspected trucks will increase highway safety, but rather whether the incrementa] (and arguably cumulative) inspections mandated by Pennsylvania will be accompanied by safety gains of a magnitude sufficient to justify the rather sizeable restrictions placed on interstate commerce by the statute.
Despite the mass of evidence introduced by both sides, the record is barren of any indication that the Commonwealth’s periodic inspection requirement will lead to a significant decrease in the accident rates for motor carrier vehicles. As the district court observed, because inspections “will only detect the condition of the vehicle at the time the inspection is made,” and because structural and mechanical deterioration occurs “slowly and progressively” over time, “[m]echanical failures can and do occur without warning and despite inspection of the vehicle.” Id. at 1332, 1338. From this and other evidence, the district court concluded that “inspections do not lead to a reduction in accidents caused by mechanical *806failures.” Id. at 1332. While such a conclusion might be somewhat overstated, unlike the majority I do not believe it is clearly erroneous, given that the far more frequent BMCS-mandated inspections currently required are unable to prevent many defect-related accidents.
In this connection, it is worth noting that the Commonwealth’s own Report on Motor Vehicle Inspection, dated January 1981, concluded that “it is unlikely that [periodic motor vehicle inspection] actually can prevent those outages or failures, or substantially reduce the number of frequently occurring component defects existing in vehicles in use on public highways.” According to the Report, “this study confirms the findings of several others which have concluded that accident rates among states with annual and semiannual inspections are essentially the same as those in states with no vehicle inspection programs.” Id. at 1331 n.17 & 1332 n.23. As the majority notes, see at 797-798, this report questioned the virtue of inspections for all vehicles— including, but not specifically considering, trucks — and therefore may not be directly on point. Nonetheless, in my view, the study’s findings serve to buttress the conclusions about truck inspections drawn from the record in this ease by the district court.9
I am not persuaded, moreover, by three evidentiary items relied on by the' Commonwealth in support of its argument that periodic inspections will reduce motor carrier vehicle accident rates. First, for the reasons identified by the district court, see American Trucking, supra, 515 F.Supp. at 1330 n.13, the results of various on-site examinations conducted by BMCS and Pennsylvania do not demonstrate that mandatory inspections increase highway safety. As the majority recognizes, at 799, all of these surveys “suffer from serious flaws which undermine their utility.” Second, Pennsylvania — and the majority, see id. —emphasize that 8.8% of the tractor-trailers involved in accidents in the Commonwealth in 1979 had a vehicle failure cited as a contributing cause. This statistic does no more than state the problem, however; nothing in the record indicates that the percentage will decrease once additional (and arguably cumulative) vehicle inspections are under way. Finally, Pennsylvania — and the majority, see id. at 798 stress expert testimony to the effect that potential mechanical failures can be detected by an inspection and that the Commonwealth’s envisioned program “will detect, prevent, [and] correct conditions before they reach the final stage of failure.” Appendix at 666, 684. This testimony, while of course helpful to the Commonwealth, does not go to what I consider to be the crucial question: whether the newly ordered inspections will increase highway safety to a degree sufficient to justify the sizeable burdens placed on interstate commerce by the statute.
In sum, in the absence of a showing on the part of the Commonwealth that its inspection effort, if implemented, would measurably decrease the number of accidents involving interstate trucks, I would hold that, under the balancing test, the undisputed burdens on interstate commerce resulting from Pennsylvania’s inspection program outweigh what the district court found to be speculative and unsubstantiated promises of improved highway safety.10
*807III
For more than a century, the Supreme Court has recognized that, under certain circumstances, the commerce clause can serve as an affirmative limitation on the regulatory powers of the states, even in the absence of preemptive national legislation in a particular area. See, e.g., Cooley v. Board of Wardens, 53 U.S. (12 How.) 299, 13 L.Ed. 996 (1851); The Passenger Cases, 48 U.S. (7 How.) 283, 12 L.Ed. 702 (1849). In the words of Justice Frankfurter,
the Commerce Clause was not merely an authorization to Congress to enact laws for the protection and encouragement of commerce among the States, but by its own force created an area of trade free from interference by the States. . . . [T]he Commerce Clause even without implementing legislation by Congress is a limitation upon the power of the States.
Freeman v. Hewit, 329 U.S. 249, 252, 67 S.Ct. 274, 276, 91 L.Ed. 265 (1946).
There can be no doubt that Pennsylvania, like every other state, has an interest in increasing the safety of its highways; there also can be no doubt that the Commonwealth is entitled to “great leeway” in acting to realize this objective. See Railway Express Agency, Inc. v. New York, 336 U.S. 106, 111, 69 S.Ct. 463, 93 L.Ed. 533 (1949). In the Bibb-Raymond Motor-Kassel trilogy, however, the Supreme Court stressed that, even in the traditionally local domain of highway safety regulation, states cannot unduly fetter commercial interchange within the Union. As a result of today’s decision, Pennsylvania will be the only state in the nation to restrict access to its highways to those trucks that have received a state-sponsored safety inspection.11 In my view, this action will have a considerable negative impact on interstate commerce, and Pennsylvania has been unable to demonstrate safety benefits sufficient to offset this burden. Accordingly, I conclude that “[t]his is one of those cases — few in number — where local safety measures that are nondiscriminatory place an unconstitutional burden on interstate commerce.” Bibb, supra, 359 U.S. at 529, 79 S.Ct. at 967. Thus, I respectfully dissent.
. It is tempting to conclude, as does the majority in this case, see at 794, that a majority of the Supreme Court in Kassel v. Consolidated Freightways Corp., 450 U.S. 662, 101 S.Ct. 1309, 67 L.Ed.2d 580 (1981), rejected the use of a balancing test in evaluating the constitutionality of safety-related legislation. To be sure, three Justices (only two of whom, however, remain on the Court) sharply criticized the plurality’s balancing approach. The significance of Justice Brennan’s concurring opinion (which was joined by Justice Marshall) is more difficult to assess. Both Justices Brennan and Marshall joined the opinion of the Court in Raymond Motor Transp., Inc. v. Rice, 434 U.S. 429, 98 S.Ct. 787, 54 L.Ed.2d 664 (1978), in which a balancing test was employed. Then, too, Justice Brennan’s concurring opinion in Kassel does not directly take issue with the observation of the plurality that “Justice Brennan finds *802it unnecessary to reach the Raymond analysis because he finds the Iowa statute to be flawed for a threshold reason” (viz, that the Iowa act constituted “protectionist legislation”). 450 U.S. at 679 n.27, 101 S.Ct. at 1320 n.27. Moreover, Justice Brennan’s concurrence in Kassel stressed that the appropriate focus in commerce clause cases should be on “the [actual] regulatory purposes identified by the lawmakers and on the evidence before or available to them that might have supported their judgment.” Id. at 680, 101 S.Ct. at 1320. With respect to the matter sub judice, however, no legislative discussion accompanied the Commonwealth’s enactment of the truck inspection statute. See American Trucking Ass’ns, Inc. v. Larson, 515 F.Supp. 1327, 1329 n.4 (M.D.Pa.1981). In Kassel, Justice Brennan emphasized that “[w]here there is no evidence bearing on the actual purpose for a legislative classification, our analysis necessarily focuses on the suggestions of counsel,” and therefore “ ‘marginally more demanding scrutiny’ is appropriate to ‘test the plausibility of the tendered purpose.’ ” 450 U.S. at 682 n.3, 101 S.Ct. at 1322 n.3 (quoting Schweiker v. Wilson, 450 U.S. 221, 245, 101 S.Ct. 1074, 1086, 67 L.Ed.2d 186 (1981) (Powell, J., dissenting)). A reading of the relevant cases, then, convinces me that to date no single approach to the commerce clause has attracted a majority of the Justices. I also note that, very recently, seven Justices joined in applying the balancing test (as set forth in Pike v. Bruce Church, Inc., 397 U.S. 137, 142, 90 S.Ct. 844, 847, 25 L.Ed.2d 174 (1970)) to a state statute deemed by the Court to fall into the “health and safety regulation” category. See Sporhase v. Nebraska, - U.S. -, -, 102 S.Ct. 3456, 3464, 73 L.Ed.2d 1254 (1982).
. See, e.g., Baldwin v. G.A.F. Seelig, Inc., 294 U.S. 511, 527, 55 S.Ct. 497, 502, 79 L.Ed. 1032 (1935) (“one state in its dealings with another may not place itself in a position of economic isolation” because “[Restrictions so contrived are an unreasonable clog upon the mobility of commerce”); The Supreme Court, 1980 Term, 95 Harv.L.Rev. 91, 101-02 (1981) (arguing that increased state economic regulation, and the resulting nonuniformity, may undercut federal efforts at deregulation and may force the Court “to defend national interests more strenuously in the future”).
. It has been maintained, see Kassel v. Consolidated Freightways Corp., 450 U.S. 662, 690, 101 S.Ct. 1309, 1326, 67 L.Ed.2d 580 (1981) (Rehnquist, J., dissenting); Eule, Laying the Dormant Commerce Clause to Rest, 91 Yale L.J. 425, 435-37 (1982), that courts should defer to state regulations that impinge on interstate commerce, on the ground that, with respect to any given state statute, non-action by Congress must imply consent. To date, however, the Supreme Court has neither endorsed nor demanded this type of judicial restraint. Moreover, it is arguable that increased judicial deference would be unwise because, at least as a de facto matter, for many years Congress has deferred to the federal courts to police and protect the commercial interests of the nation. See Gibbons, Keynote Address, Symposium: Constitutional Adjudication and Democratic Theory, 56 N.Y.U.L.Rev. 260, 264-65 (1981) (defending the Supreme Court’s dormant commerce clause jurisprudence on the ground that “[ujsually the Court majority believed it was expressing the true will of the national majority”) (emphasis added).
. The balancing test favored by the Kassel plurality can be traced to Bibb v. Navajo Freight Lines, Inc., 359 U.S. 520, 79 S.Ct. 962, 3 L.Ed.2d 1003 (1959), in which the Court invalidated an Illinois requirement (unique to that State) that truckers install contoured mudflaps on their vehicles. According to the Justices, because “ ‘the total effect of the law as a safety measure in reducing accidents and casualties is so slight or problematical as not to outweigh the national interest in keeping interstate commerce free from interferences which seriously impede it,’ ” the statute could not be upheld. Id. at 524, 79 S.Ct. at 964 (quoting Southern Pac. Co. v. Arizona, 325 U.S. 761, 775-76, 65 S.Ct. 1515, 1523, 89 L.Ed. 1915 (1945)). The Bibb standard was invoked and refined in Raymond Motor Transp., Inc. v. Rice, 434 U.S. 429, 98 S.Ct. 787, 54 L.Ed.2d 644 (1978) (invalidating a Wisconsin statute governing the length and configuration of trucks): “Our recent decisions make clear that the inquiry necessarily involves a sensitive consideration of the weight and nature of the state regulatory concern in light of the extent of the burden imposed on the course of interstate commerce.” Id. at 441, 98 S.Ct. at 794; see also Edgar v. Mite Corp., - U.S. -, ---, 102 S.Ct. 2629, 2640-43, 73 L.Ed.2d 269 (1982); Pike v. Bruce Church, Inc., 397 U.S. 137, 142, 90 S.Ct. 844, 847, 25 L.Ed.2d 174 (1970).
. In fact, this one million figure may represent an underestimation of the actual impact of the Commonwealth’s inspection program. The district court found that, although 25 states currently have “some type of periodic inspection program,” 6 states exempt from inspection all interstate motor carrier vehicles subject to regulation by the federal Bureau of Motor Carrier Safety (BMCS), and several states have “atypical inspection procedures.” American Trucking, supra, 515 F.Supp. at 1330.
. Given the strategic geographic location of the Commonwealth, it is difficult to imagine that circumnavigation would constitute a viable option for most interstate motor carriers. Nonetheless, the district court found that, if this alternative were seriously pursued, the resulting additional transportation costs (measured in both money and time) would be “enormous.” American Trucking, supra, 515 F.Supp. at 1334.
. Additionally, although the district court made no specific findings with respect to these charges, the record contains other, generally unrebutted, allegations by the plaintiffs as to burdens imposed on interstate commerce by the Commonwealth’s inspection requirement: many companies would be forced to purchase additional vehicles in order to prevent a diminution or cessation of service during the time when their existing trucks are being inspected; it is questionable whether the Commonwealth has a sufficient number of service stations to handle the marked increase in periodic inspections; because of “prohibitive” costs associated with the inspection process, a number of trucking companies allegedly would be forced to discontinue or suspend service to Pennsylvania and other east coast areas, leading to greater unemployment in the region; many companies reported the costs they expected to incur in complying with the Pennsylvania law to be far in excess of the $150,000 figure identified by Coastal as its annual cost.
. According to the district court, “[u]nder BMCS regulations, every motor carrier must require its drivers to prepare a report at the completion of each day’s work with the vehicle covering [specified] parts and accessories”; “[a]ny defects or deficiencies affecting the safety of operation of the motor vehicle or resulting in its mechanical breakdown must be reported by the driver”; “[b]efore a driver takes out a motor carrier vehicle, he must .. . visually inspect it, satisfy himself that it is in safe operating condition, review the most recent inspection report carried on the vehicle, and sign the report only if . .. [the] safety-related defects or deficiencies have been repaired.” American Trucking, supra, 515 F.Supp. at 1332.
. The fact that the Report was not introduced into evidence, and therefore arguably cannot be employed to support a holding, does not mean a court is without power to use this public document, as did the district court, to corroborate an already-arrived-at result.
. I am constrained to note that, if I agreed with the majority that the deferential standard of commerce clause review is preferable to the balancing test, in my opinion Pennsylvania would prevail on this appeal. While I believe that the evidence proffered by the Commonwealth in support of its inspection proposal is insufficient to offset the truckers’ showing of a sizeable negative impact on interstate commerce, I simply cannot conclude that the safety benefits to be realized by the Pennsylvania legislation are “illusory” or “demonstrably trivial” (quoting Kassel v. Consolidated Freightways Corp., 450 U.S. 662, 692, 101 S.Ct. 1309, 1327, 67 L.Ed.2d 580 (1982) (Rehnquist, J., dissenting)). The majority implies, see at 795, that selection of the appropriate level of review in this matter is “outcome determinative.” I agree.
. “A State which insists on a design out of line with the requirements of almost all the other States may sometimes place a great burden of delay and inconvenience on those interstate motor carriers entering or crossing its territory. Such a new safety device — out of line with the requirements of the other States — may be so compelling that the innovating State need not be the one to give way. But the present showing — balanced against the clear burden on commerce — is far too inconclusive.” Bibb v. Navajo Freight Lines, Inc., 359 U.S. 520, 529-30, 79 S.Ct. 962, 967-68, 3 L.Ed.2d 1003 (1959).