with whom The Chief Justice and Justice Stewart join, dissenting.
The result in this case suggests, to paraphrase Justice Jackson, that the only state truck-length limit “that is valid is one which this Court has not been able to get its hands on.” Jungersen v. Ostby & Barton Co., 335 U. S. 560, 572 (1949) (dissenting opinion). Although the plurality opinion and the opinion concurring in the judgment strike down Iowa’s law by different routes, I believe the analysis in both opinions oversteps our “limited authority to review state legislation under the commerce clause,” Locomotive Firemen v. Chicago, R. I. & P. R. Co., 393 U. S. 129, 136 (1968), and seriously intrudes upon the fundamental right of the States to pass laws to secure the safety of their citizens. Accordingly, I dissent.
I
It is necessary to elaborate somewhat on the facts as presented in the plurality opinion to appreciate fully what the Court does today. Iowa’s action in limiting the length of trucks which may travel on its highways is in no sense un*688usual. Every State in the Union regulates the length of vehicles permitted to use the public roads. Nor is Iowa a renegade in having length limits which operate to exclude the 65-foot doubles favored by Consolidated. These trucks are prohibited in other areas of the country as well, some 17 States and the District of Columbia, including all of New England and most of the Southeast.1 While pointing out that Consolidated carries commodities through Iowa on Interstate 80, “the principal east-west route linking New York, Chicago, and the west coast,” ante, at 665, the plurality neglects to note that both Pennsylvania and New Jersey, through which Interstate 80 runs before reaching New York, also ban 65-foot doubles. In short, the persistent effort in the plurality opinion to paint Iowa as an oddity standing alone to block commerce carried in 65-foot doubles is simply not supported by the facts.
Nor does the plurality adequately convey the extent to which the lower courts permitted the 65-foot doubles to operate in Iowa. Consolidated sought to have the 60-foot length limit declared an unconstitutional burden on commerce when applied to the seven Interstate Highways in Iowa2 and “access routes to and from Plaintiff’s terminals, and reasonable access from said Interstate Highways to facilities for food, fuel, repairs, or rest.” App. 10. The lower courts granted this relief, permitting the 65-foot doubles to travel off the Interstates as far as five miles for access to terminal and *689other facilities, or less if closer facilities were available. 475 F. Supp. 544, 553-554 (SD Iowa 1979). To the extent the plurality relies on characteristics of the Interstate Highways in rejecting Iowa’s asserted safety justifications, see ante, at 672-673, it fails to recognize the scope of the District Court order it upholds.
With these additions to the relevant facts, we can now examine the appropriate analysis to be applied.
II
Casual readers of this Court’s Commerce Clause decisions may be surprised, upon turning to the Constitution itself, to discover that the Clause in question simply provides that “The Congress shall have Power ... To regulate Commerce . . . among the several States.” Art. I, § 8, cl. 3. Although it is phrased in terms of an affirmative grant of power to the National Legislature, we have read the Commerce Clause as imposing some limitations on the States as well, even in the absence of any action by Congress. See Philadelphia v. New Jersey, 437 U. S. 617, 623 (1978). The Court has hastened to emphasize, however, that the negative implication it has discerned in the Commerce Clause does not invalidate state legislation simply because the legislation burdens interstate commerce.
“In determining whether the state has imposed an undue burden on interstate commerce, it must be borne in mind that the Constitution when 'conferring upon Congress the regulation of commerce, . . . never intended to cut the States off from legislating on all subjects relating to the health, life, and safety of their citizens, though the legislation might indirectly affect the commerce of the country.’ ” Huron Portland Cement Co. v. Detroit, 362 U. S. 440, 443-444 (1960) (quoting Sherlock v. Ailing, 93 U. S. 99, 103 (1876)).
See Raymond Motor Transportation, Inc. v. Rice, 434 U. S. *690429, 440 (1978); Southern Pacific Co. v. Arizona, 325 U. S. 761, 767 (1945). The Commerce Clause is, after all, a grant of authority to Congress, not to the courts. Although the Court when it interprets the “dormant” aspect of the Commerce Clause will invalidate unwarranted state intrusion, such action is a far cry from simply undertaking to regulate when Congress has not because we believe such regulation would facilitate interstate commerce. Cf. Northwest Airlines, Inc. v. Minnesota, 322 U. S. 292, 302 (1944) (Black, J., concurring) (“The Constitution gives [Congress] the power to regulate commerce among the states, and until it acts I think we should enter the field with extreme caution”).
It is also well established that “the Court has been most reluctant to invalidate under the Commerce Clause ‘state legislation in the field of safety where the propriety of local regulation has long been recognized.’ ” Raymond, supra, at 443 (quoting Pike v. Bruce Church, Inc., 397 U. S. 137, 143 (1970)). The propriety of state regulation of the use of public highways was explicitly recognized in Morris v. Duby, 274 U. S. 135, 143 (1927), where Chief Justice Taft wrote that “[i]n the absence of national legislation especially covering the subject of interstate commerce, the State may rightfully prescribe uniform regulations adapted to promote safety upon its highways and the conservation of their use, applicable alike to vehicles moving in interstate commerce and those of its own citizens.” The Court very recently reaffirmed the longstanding view that “[i]n no field has . . . deference to state regulation been greater than that of highway safety.” Raymond, supra, at 443. See Railway Express Agency, Inc. v. New York, 336 U. S. 106, 111 (1949); South Carolina State Highway Dept. v. Barnwell Brothers, Inc., 303 U. S. 177, 187 (1938); Sproles v. Binford, 286 U. S. 374, 390 (1032); Hendrick v. Maryland, 235 U. S. 610, 622 (1915). Those challenging a highway safety regulation must overcome a “strong presumption of validity,” Bibb v. Navajo Freight Lines, Inc., 359 U. S. 520, 524 (1959), particularly *691when, as here, Congress has not acted in the area and the claim is that “the bare possession of power by Congress” invalidates the state legislation. Barnwell Brothers, supra, at 187.3
A determination that a state law is a rational safety measure does not end the Commerce Clause inquiry. A “sensitive consideration” of the safety purpose in relation to the burden on commerce is required. Raymond, supra, at 441. When engaging in such a consideration the Court does not directly compare safety benefits to commerce costs and strike down the legislation if the latter can be said in some vague sense to “outweigh” the former. Such an approach would make an empty gesture of the strong presumption of validity accorded state safety measures, particularly those governing highways. It would also arrogate to this Court functions of forming public policy, functions which, in the absence of congressional action, were left by the Framers of the Constitution to state legislatures. “[I]n reviewing a state highway regulation where Congress has not acted, a court is not called upon, as are state legislatures, to determine what, in its judgment, is the most suitable restriction to be applied of those that are possible, or to choose that one which in its opinion is best adapted to all the diverse interests affected.” Barnwell Brothers, supra, at 190. See Locomotive Firemen, 393 U. S., at 138 (“[T]he question'of safety in the circumstances of this case is essentially a matter of public policy, and public policy can, under our constitutional system, be fixed only by the people acting through their elected representatives”); Bibb, supra, at 524 (“If there are alternative ways of solving a problem, we do not sit to determine which of them is best *692suited to achieve a valid state objective. Policy decisions are for the state legislature”)- These admonitions are peculiarly apt when, as here, the question involves the difficult comparison of financial losses and “the loss of lives and limbs of workers and people using the highways.” Locomotive Firemen, supra, at 140.4
The purpose of the “sensitive consideration” referred to above is rather to determine if the asserted safety justification, although rational, is merely a pretext for discrimination against interstate commerce. We will conclude that it is if the safety benefits from the regulation are demonstrably trivial while the burden on commerce is great. Thus the Court in Bibb stated that the “strong presumption of validity” accorded highway safety measures could be overcome only when the safety benefits were “slight or problematical,” 359 U. S., at 524. See Raymond, 434 U. S., at 449 (Blackmun, J., concurring) (“[I]f safety justifications are not illusory, the Court will not second-guess legislative judgment about their importance in comparison with related burdens on interstate commerce”). The nature of the inquiry is perhaps best illustrated by examining those cases in which state safety laws have been struck down on Commerce Clause grounds. In Southern Pacific a law regulating train lengths was viewed by the Court as having “at most slight and dubious advantage, if any, over unregulated train lengths,” 325 U. S., at 779; the lower courts concluded the law actually tended to increase the number of accidents by increasing the number of trains, id., at 777. In Bibb the contoured mudguards re*693quired by Illinois, alone among the States, had no safety advantages over conventional mudguards and, as in Southern Pacific, actually increased hazards. 359 U. S., at 525; id., at 530 (Harlan, J., concurring). In Great A&P Tea Co. v. Cottrell, 424 U. S. 366, 375-376 (1976), the Court struck down a Mississippi “reciprocity clause” concerning milk inspection because it “disserve[d] rather than promote[d] any higher Mississippi milk quality standards.” The cases thus demonstrate that the safety benefits of a state law must be slight indeed before it will be struck down under the dormant Commerce Clause.
Ill
Iowa defends its statute as a highway safety regulation. There can be no doubt that the challenged statute is a valid highway safety regulation and thus entitled to the strongest presumption of validity against Commerce Clause challenges. As noted, all 50 States regulate the length of trucks which may use their highways. Cf. West Coast Hotel Co. v. Parrish, 300 U. S. 379, 399 (1937) (“The adoption of similar requirements by many States evidences a deepseated conviction both as to the presence of the evil and as to the means adapted to check it”). The American Association of State Highway and Transportation Officials (AASHTO) has consistently recommended length as well as other limits on vehicles.5 The Iowa Supreme Court has long viewed the provision in question as intended to promote highway safety, see Wood Brothers Thresher Co. v. Eicher, 231 Iowa 550, 559-560, 1 N. W. 2d 655, 660 (1942); State v. United-Buckingham Freight Lines, Inc., 211 N. W. 2d 288, 290 (1973), and “[t]his Court has also had occasion to point out that the sizes and weights of automobiles have an important relation *694to the safe and convenient use of the highways, which are matters of state control.” Maurer v. Hamilton, 309 U. S. 598, 609 (1940). There can also be no question that the particular limit chosen by Iowa — 60 feet — is rationally related to Iowa’s safety objective. Most truck limits are between 55 and 65 feet, see App. 645, and Iowa’s choice is thus well within the widely accepted range.
Iowa adduced evidence supporting the relation between vehicle length and highway safety. The evidence indicated that longer vehicles take greater time to be passed, thereby increasing the risks of accidents, particularly during the inclement weather not uncommon in Iowa. Id., at 504-505. The 65-foot vehicle exposes a passing driver to visibility-impairing splash and spray during bad weather for a longer period than do the shorter trucks permitted in Iowa.6 Longer trucks are more likely to clog intersections, id., at 457, and although there are no intersections on the Interstate Highways, the order below went beyond the highways themselves and the concerns about greater length at intersections would arise “[a]t every trip origin, every trip destination, every intermediate stop for picking up trailers, reconfiguring loads, change of drivers, eating, refueling — every intermediate stop would generate this type of situation.” Ibid. The Chief of the Division of *695Patrol in the Iowa Department of Public Safety testified that longer vehicles pose greater problems at the scene of an accident. For example, trucks involved in accidents often must be unloaded at the scene, id., at 400, which would take longer the bigger the load.
In rebuttal of Consolidated’s evidence on the relative safety of 65-foot doubles to trucks permitted oh Iowa’s highways, Iowa introduced evidence that doubles are more likely than singles to jackknife or upset, id., at 507. The District Court concluded that this was so and that singles are more stable than doubles. 475 F. Supp., at 549.7 Iowa also introduced evidence from Consolidated’s own records showing that Consolidated’s overall accident rate for doubles exceeded that of semis for three of the last four years, App. 668-675, and that some of Consolidated’s own drivers expressed a preference for the handling characteristics of singles over doubles. 475 F. Supp., at 549.
In addition Iowa elicited evidence undermining the probative value of Consolidated’s evidence. For example, Iowa established that the more experienced drivers tended to drive doubles, because they have seniority and driving doubles is a higher paying job than driving singles. Since the leading cause of accidents was driver error, Consolidated’s evidence of the relative safety record of doubles may have been based in large part not on the relative safety of the vehicles themselves but on the experience of the drivers. App. 27-28. Although the District Court, the Court of Appeals, and the plurality all fail to recognize the fact, Iowa also negated much of Consolidated’s evidence by establishing that it considered the relative safety of doubles to singles, and not the question of length alone. Consolidated introduced much *696evidence that its doubles were as safe as singles. See, e. g., id., at 23, 32-36, 45, 89, 153, 289, 304, 586, 609. Such evidence is beside the point. The trucks which Consolidated wants to run in Iowa are prohibited because of their length, not their configuration. Doubles are allowed in Iowa, up to a length of 60 feet, and Consolidated in fact operates 60-foot doubles in Iowa. Consolidated’s experts were often forced to admit that they could draw no conclusions about the relative safety of 65-foot doubles and 60-foot doubles, as opposed to doubles and singles. See, e. g., id., at 26, 53, 308. Conclusions that the double configuration is as safe as the single do not at all mean the 65-foot double is as safe as the 60-foot double, or that length is not relevant to vehicle safety. For example, one of Consolidated’s experts testified that doubles “off track” better than singles, because of their axle placement, but conceded on cross-examination that a 60-foot double would off-track better than a 65-foot double. Id., at 97, 107. In sum, there was sufficient evidence presented at trial to support the legislative determination that length is related to safety, and nothing in Consolidated’s evidence undermines this conclusion.
The District Court approached the case as if the question were whether Consolidated’s 65-foot trucks were as safe as others permitted on Iowa highways, and the Court of Appeals as if its task were to determine if the District Court’s factual findings in this regard were “clearly erroneous.” 612 F. 2d, at 1069. The question, however, is whether the Iowa Legislature has acted rationally in regulating vehicle lengths and whether the safety benefits from this regulation are more than slight or problematical. “The classification of the traffic for the purposes of regulation ... is a legislative, not a judicial, function. Its merits are not to be weighed in the judicial balance and the classification rejected merely because the weight of the evidence in court appears to favor a different standard.” Clark v. Paul Gray, Inc., 306 U. S. 583, 594 (1939). “Since the adoption of one weight or width regula*697tion, rather than another, is a legislative and not a judicial choice, its constitutionality is not to be determined by weighing in the judicial scales the merits of the legislative choice and rejecting it if the weight of evidence presented in court appears to favor a different standard.” Barnwell Brothers, 303 U. S., at 191.8
The answering of the relevant question is not appreciably advanced by comparing trucks slightly over the length limit with those at the length limit. It is emphatically not our task to balance any incremental safety benefits from prohibiting 65-foot doubles as opposed to 60-foot doubles against the burden on interstate commerce. Lines drawn for safety purposes will rarely pass muster if the question is whether a slight increment can be permitted without sacrificing safety. As Justice Holmes put it:
“When a legal distinction is determined, as no one doubts that it may be, between night and day, childhood *698and maturity, or any other extremes, a point has to be fixed or a line has to be drawn, or gradually picked out by successive decisions, to mark where the change takes place. Looked at by itself without regard to the necessity behind it the line or point seems arbitrary. It might as well or nearly as well be a little more to one side or the other. But when it is seen that a line or point there must be, and that there is no mathematical or logical way of fixing it precisely, the decision of the legislature must be accepted unless we can say that it is very wide of any reasonable mark.” Louisville Gas & Electric Co. v. Coleman, 277 U. S. 32, 41 (1938) (dissenting opinion).
The question is rather whether it can be said.that the benefits flowing to Iowa from a rational truck-length limitation are “slight or problematical.” See Bibb, 359 U. S., at 524. The particular line chosen by Iowa — 60 feet — is relevant only to the question whether the limit is a rational one. Once a court determines that it is, it considers the overall safety benefits from the regulation against burdens on interstate commerce, and not any marginal benefits from the scheme the State established as opposed to that the plaintiffs desire. See Southern Pacific, 325 U. S., at 779 (train-length law struck down because it “affords at most slight and dubious advantage, if any, over unregulated train lengths”) (emphasis supplied) ; Barnwell Brothers, supra, at 190-192.
The difficulties with the contrary approach are patent. While it may be clear that there are substantial safety benefits from a 55-foot truck as compared to a 105-foot truck, these benefits may not be discernible in 5-foot jumps. Appellee’s approach would permit what could not be accomplished in one lawsuit to be done in 10 separate suits, each challenging an additional five feet.
Any direct balancing of marginal safety benefits against burdens on commerce would make the burdens on commerce the sole significant factor, and make likely the odd result that *699similar state laws enacted for identical safety reasons might violate the Commerce Clause in one part of the country but not another. For example, Mississippi and Georgia prohibit trucks over 55 feet. Since doubles are not operated in the Southeast, the demonstrable burden on commerce may not be sufficient to strike down these laws, while Consolidated maintains that it is in this case, even though the doubles here are given an additional five feet. On the other hand, if Consolidated were to win this case it could shift its 65-foot doubles to routes leading into Mississippi or Georgia (both States border States in which 65-foot trucks are permitted) and claim the same constitutional violation it claims in this case. Consolidated Freightways, and not this Court, would become the final arbiter of the Commerce Clause.
It must be emphasized that there is nothing in the laws of nature which make 65-foot doubles an obvious norm. Consolidated operates 65-foot doubles on many of its routes simply because that is the largest size permitted in many States through which Consolidated travels. App. 92, 240, 364-365. Doubles can and do come in smaller sizes; indeed, when Iowa adopted the present 60-foot limit in 1963, it was in accord with AASHTO recommendations. Striking down Iowa’s law because Consolidated has made a voluntary business decision to employ 65-foot doubles, a decision based on the actions of other state legislatures,-would essentially be compelling Iowa to yield to the policy choices of neighboring States. Under our constitutional scheme, however, there is only one legislative body which can pre-empt the rational policy determination of the Iowa Legislature and that is Congress. Forcing Iowa to yield to the policy choices of neighboring States perverts the primary purpose of the Commerce Clause, that of vesting power to regulate interstate commerce in Congress, where all the States are represented. In Barnwell Brothers, the Court upheld a South Carolina width limit of 90 inches even though “all other states permit a width of 96 inches, which is the standard width of trucks engaged in interstate *700commerce.” 303 U. S., at 184. Then Justice Stone, writing for the Court, stressed:
“The fact that many states have adopted a different standard is not persuasive. . . . The legislature, being free to exercise its own judgment, is not bound by that of other legislatures. It would hardy be contended that if all the states had adopted a single standard none, in the light of its own experience and in the exercise Of its judgment upon all the complex elements which enter into the problem, could change it.” Id., at 195-196.
See also Sproles, 286 U. S., at 390. Nor is Iowa’s policy preempted by Consolidated’s decision to invest in 65-foot trucks, particularly since this was done when Iowa’s 60-foot limit was on the books. Cf. id., at 390-391.9
The Court of Appeals felt compelled to reach the result it did in light of our decision in Raymond and the plurality agrees that “[t]his case is Raymond revisited,” ante, at 671.10 Raymond, however, does not control this case. The Court in Raymond emphasized that “[o]ur holding is a narrow one, for we do not decide whether laws of other States restricting the operation of trucks over 55 feet long, or of double-trailer trucks, would be upheld if the evidence produced on the safety *701issue were not so overwhelmingly one-sided as in this case.” 434 U. S., at 447.11 The Raymond Court repeatedly stressed that the State “made no effort to contradict . . . evidence of comparative safety with evidence of its own,” id., at 437, that •the trucking companies’ evidence was “uncontroverted,” id., at 445, n. 19, and that the State “virtually defaulted in its defense of the regulations as a safety measure,” id., at 444. By contrast, both the District Court and the Court of Appeals recognized that Iowa “made an all out effort” and “zealously presented arguments” on its safety case. 475 F. Supp., at 548; 612 F. 2d, at 1067-1068. As noted, Iowa has adduced evidence sufficient to support its safety claim and has rebutted much of the evidence submitted by Consolidated.
Furthermore, the exception to the Wisconsin prohibition which the Court specifically noted in Raymond finds no parallel in this case. The exception in Raymond permitted oversized vehicles to travel from plant to plant in Wisconsin or between a Wisconsin plant and the border. 434 U. S., at 446, and n. 24. As the Court noted, this discriminated on its face between Wisconsin industries and the industries of other States. The border-cities exception to the Iowa length limit does not. Iowa shippers in cities with border-city ordinances may use longer vehicles in interstate commerce, but interstate shippers coming into such cities may do so as well. Cities without border-city ordinances may neither export nor import on oversized vehicles. Nor can the border-cities exception be “[v]iewed realistically,” as was the Wisconsin exception, to “be the product of compromise between forces within the State that seek to retain the State’s general truck-length limit, and industries within the State that complain that the general limit is unduly burdensome.” Raymond, 434 U. S., at 447. The Wisconsin exception was available to all Wisconsin industries wanting to ship out of State from Wis-*702cousin plants. The border-cities exception is of much narrower applicability: only 5 of Iowa’s 16 largest cities and only 8 cities in all permit oversized trucks under the border-cities exception. The population of the eight cities with border-city ordinances is only 13 percent of the population of the State.12
My Brother Brennan argues that the Court should consider only the purpose the Iowa legislators actually sought to achieve by the length limit, and not the purposes advanced by Iowa’s lawyers in defense of the statute. This argument calls to mind what was said of the Roman Legions: that they may have lost battles, but they never lost a war, since they never let a war end until they had won it. The argument has been consistently rejected by the Court in other contexts, compare, e. g., United, States Railroad Retirement Board v. Fritz, 449 U. S. 166, 187-188 (1980), with id., at 187-188 (Brennan, J., dissenting), and Michael M. v. Superior Court of Sonoma County, ante, at 469-470 (plurality opinion), with ante, at 494-496 (Brennan, J., dissenting), and Justice Brennan can cite no authority for the proposition that possible legislative purposes suggested by a State’s lawyers should not be considered in Commerce Clause cases. The problems with a view such as that advanced in the opinion concurring in the judgment are apparent. To name just a few, it assumes that individual legislators are motivated by one discernible “actual” purpose, and ignores the fact that different legislators may vote for a single piece of legislation for widely *703different reasons. See Michael M., ante, at 469-470; Arlington Heights v. Metropolitan Housing Dev. Corp., 429 U. S. 252, 265 (1977); McGinnis v. Royster, 410 U. S. 263, 276-277 (1973). How, for example, would a court adhering to the views expressed in the opinion concurring in the judgment approach a statute, the legislative history of which indicated that 10 votes were based on safety considerations, 10 votes were based on protectionism, and the statute passed by a vote of 40-20? What would the actual purpose of the legislature have been in that case? This Court has wisely “never insisted that a legislative body articulate its reasons for enacting a statute.” Fritz, supra, at 461.13
*704Both the plurality and the concurrence attach great significance to the Governor’s veto of a bill passed by the Iowa Legislature permitting 65-foot doubles. Whatever *705views one may have about the significance of legislative motives, it must be emphasized that the law which the Court strikes down today was not passed to achieve the protectionist goals the plurality and the concurrence ascribe to the Governor. Iowa’s 60-foot length limit was established in 1963, at a time when very few States permitted 65-foot doubles. See App. to Reply Brief for Appellants la, 2a. Striking down legislation on the basis of asserted legislative motives is dubious enough, but the plurality and concurrence strike down the legislation involved in this case because of asserted impermissible motives for not enacting other legislation, motives which could not possibly have been present when the legislation under challenge here was considered and passed. Such action is, so far as I am aware, unprecedented in this Court’s history.
Furthermore, the effort in both the plurality and the concurrence to portray the legislation involved here as protectionist is in error. Whenever a State enacts more stringent safety measures than its neighbors, in an area which affects commerce, the safety law will have the incidental effect of deflecting interstate commerce to the neighboring States. Indeed, the safety and protectionist motives cannot be separated: The whole purpose of safety regulation of vehicles *706is to protect the State from unsafe vehicles. If a neighboring State chooses not to protect its citizens from the danger discerned by the enacting State, that is its business, but the enacting State should not be penalized when the vehicles it considers unsafe travel through the neighboring State.
The other States with truck-length limits that exclude Consolidated's 65-foot doubles would not at all be paranoid in assuming that they might be next on Consolidated’s “hit list.” 14 The true problem with today's decision is that it gives no guidance whatsoever to these States as to whether their laws are valid or how to defend them. For that matter, the decision gives no guidance to Consolidated or other trucking firms either. Perhaps, after all is said and done, the Court today neither says nor does very much at all. We know only that Iowa’s law is invalid and that the jurisprudence of the “negative side” of the Commerce Clause remains hopelessly confused.
Doubles are prohibited in Maine, New Hampshire, Vermont, Massachusetts (except turnpike), Rhode Island, Connecticut, Pennsylvania, West Virginia, Virginia, Tennessee, North Carolina, South Carolina, Alabama, and the District of Columbia. Doubles are permitted to a maximum length of 55 feet in New York (on designated highways only, longer permitted on turnpike), New Jersey, Mississippi, and Georgia. Sixty-five-foot doubles are restricted to designated highways in Oregon, North Dakota, Minnesota, Wisconsin, Michigan, Illinois, Missouri, Louisiana, Kentucky, Maryland, and Florida. See App. 605, 645.
Interstate Highways 80, 35, 280, 380, 29, 680, and 235.
Congress has considered the question of regulating truck length several times but has consistently left the matter for state regulation. See, e. g., S. Rep. No. 93-1111, p. 10 (1974) (“The Committee believes that truck lengths should remain, as they have been, a matter for State decision”).
It should not escape notice that a majority of the Court goes on record today as agreeing that courts in Commerce Clause cases do not sit to weigh safety benefits against burdens on commerce when the safety benefits are not illusory. See opinion concurring in judgment, ante, at 681, n. 1. Even the plurality gives lipservice to this principle, ante, at 670. I do not agree with my Brother BrenNAN, however, that only those safety benefits somehow articulated by the legislature as the motivation for the challenged statute can be considered in supporting the state law. See infra, at 702-703.
The plurality points out that “AASHTO specifically recommends that States permit 65-foot doubles,” ante, at 674, n. 16. But in the absence of its adoption by the Iowa legislative process, an AASHTO recommendation as to a particular length limit remains exactly that: a recommendation which no State is bound to follow.
Although greater passing time was offered as a safety justification in Raymond, the Court noted that the trucking companies there “produced uncontradicted evidence that the difference in passing time does not pose an appreciable threat to motorists traveling on limited access, four-lane divided highways.” 434 U. S., at 444 (emphasis supplied). That is not the case here. Iowa indicated before the trial court the connection between greater passing time and greater hazard, primarily the longer exposure to splash and spray. For a vehicle traveling at 55 miles per hour passing a truck traveling at 52 miles per hour, the additional exposure from a 65-foot truck as opposed to a 60-foot truck would be 92 feet and more than a full second. App. 505. The greater passing distance and time would become even more significant off the Interstates when oncoming traffic is involved, and the District Court order permits the longer trucks to operate off the Interstates.
Although the District Court noted that doubles are more maneuverable, it certainly is reasonable for a legislature to conclude that stability is a more critical factor than maneuverability on the straight expanses of the Interstates.
The opinion of my Brother BreNNAN concurring in the judgment mis-characterizes this dissent when it states that I assume “resolution of the case must hinge upon the argument offered by Iowa’s attorneys: that 65-foot doubles are more dangerous than shorter trucks.” Ante, at 681. I assume nothing of the sort. As noted in the immediately preceding paragraph, the point of this dissent is that the District Court and the Court of Appeals erred when they undertook to determine if the prohibited trucks were as safe as the permitted ones on the basis of evidence presented at trial. As I read this Court’s opinions, the State must simply prove, aided by a “strong presumption of validity,” that the safety benefits of its law are not illusory. I review the evidence presented at trial simply to demonstrate that Iowa made such a showing in this case, not because the validity of Iowa’s law depends on its proving by a preponderance of the evidence that the excluded trucks are unsafe. As I thought was made clear, it is my view that Iowa must simply show a relation between vehicle length limits and safety, and that the benefits from its length limit are not illusory. Iowa’s arguments on passing time, intersection obstruction, and problems at the scene of accidents have validity beyond a comparison of the 65- and 60-foot trucks. In sum, I fully agree with Justice Bren-Nan that the validity of Iowa’s length limit does not turn on whether 65-foot trucks are less safe than 60-foot trucks.
The extent to which the assertion of a violation of the Commerce Clause is simply an effort to compel Iowa to yield to the decisions of its neighbors is clearest if one asks whether Iowa’s law would violate the Commerce Clause if the 17 States which currently prohibit Consolidated’s 65-foot doubles were not in the East and Southeast but rather surrounded Iowa.
The opinion concurring in the judgment begins by stating that the regulation involved here is “nearly identical” to the one struck down in Raymond, ante, at 679, but then approaches the case in a completely different manner than the Court in Raymond. My Brother BrenNAN votes to strike down Iowa’s law not because the safety benefits of Iowa’s law are illusory — indeed, he specifically declines to consider the safety benefits — but because he views it as protectionist in nature. As I read the various opinions in this case, therefore, only four Justices invalidate Iowa’s law on the basis of the analysis in Raymond.
Justice Blackmun filed a concurring opinion, joined by three others, “to emphasize the narrow scope of [the] decision.” 434 U. S., at 448.
According to 1980 preliminary census data, the population of Iowa is 2,908,797. Cities with border-city ordinances, and their populations, are: Akron, 1,514; Bettendorf, 27,377; Clinton, 32,779; Council Bluffs, 56,269; Davenport, 103,036; Dubuque, 61,932; Hawarden, 2,719; and Sioux City, 81,434. Iowa’s largest city and capital, Des Moines, with a population of 190,910, cannot avail itself of (he border-cities exception, nor can Cedar Rapids, the second largest city, with a population of 110,124, or Waterloo, the fifth largest city, with a population of 75,535. Census Bureau, Population Division, Preliminary Count.
It is not a particularly pleasant task for the author of a dissent joined by two other Members of the Court to take issue with a statement made by the author of a concurrence in that same case which is joined by only one Member of the Court. Such fragmentation, particularly between two opinions neither of which command the adherence of a majority of the Court, cannot help but further unsettle what certainty there may be in the legal principles which govern our decision of Commerce Clause cases such as this and lay a foundation for similar uncertainty in other sorts of constitutional adjudication. Nonetheless, I feel obliged to take up the cudgels, however unwillingly, because Justice BrenNAn’s concurrence, joined by Justice Marshall, is mistaken not only in its analysis but also in its efforts to interpret the meaning of today’s decision.
Although both my Brother BrenNan and I have cited cases from the equal protection area, it is not clear that the analysis of legislative purpose in that area is the same as in the present context. It may be more reasonable to suppose that proffered purposes of a statute, whether advanced by a legislature or post hoc by lawyers, cloak impermissible aims in Commerce Clause cases than in equal protection cases. Statutes generally favor one group at the expense of another, and the Equal Protection Clause was not designed to proscribe this in the way that the Commerce Clause was designed to prevent local barriers to interstate commerce. Thus even if my Brother BrenNAN’s arguments were supportable in Commerce Clause cases, that analysis would not carry over of its own force into the realm of equal protection generally.
But even in the Commerce Clause area, his arguments arc unpersuasive. Allied Stores of Ohio, Inc. v. Bowers, 358 U. S. 522 (1959), see ante, at *704682-683, n. 3, seems to me to cut against, rather than in favor of, his position. The Court in Bowers stated:
“What were the special reasons, motives or policies of the Ohio Legislature for adopting the questioned proviso we do not know with certainty, nor is it important that we should, Southivestem Oil Co. v. Texas, 217 U. S. 114, 126, for a state legislature need not explicitly declare its purpose. But it is obvious that it may reasonably have been the purpose and policy of the State Legislature, in adopting the proviso, to encourage the construction or leasing and operation of warehouses in Ohio by non-residents with the attendant benefits to the State’s economy, or to stimulate the market for merchandise and agricultural products produced in Ohio by enabling nonresidents to purchase and hold them in the state for storage only, free from taxes, in anticipation of future needs. Other similar purposes reasonably may be conceived.” 358 U. S., at 528-529.
The statute involved in Bowers was upheld on the basis of the various purposes which “reasonably may be conceived,” without any effort to determine what the “actual” purpose was or any requirement that the purposes being considered somehow have been articulated by the lawmakers. Wheeling Steel Corp. v. Glander, 337 U. S. 562 (1949), simply did not consider the present question, since the State in Glander did not proffer any possible purposes beyond the one stated by the legislature in the statute.
Nor do the more recent decisions cited by my Brother BRENNAN support his argument. For example, the fact that we “need not . . . accept at face value assertions of legislative purposes, when an examination of the legislative scheme and its history demonstrates that the asserted purpose could not have been a goal of the legislation,” Weinberger v. Wiesenfeld, 420 U. S. 636, 648, n. 16 (1975) (emphasis supplied), hardly supports the proposition that we cannot consider assertions of legislative purpose which could have been a goal of the legislation, even though such purposes may not have been identified as goals by the legislature. To take another example, the upholding of the law in Massachusetts Board of Retirement v. Murgia, 427 U. S. 307, 314 (1976), because it “rationally furthers the purpose identified by the State,” certainly does not suggest that by “State” this Court meant only “legislature,” and not the State’s attorneys, or that only those purposes identified by the State could be considered in reviewing legislation.
Although Justice BREnnan “would emphasize” the significance the *705plurality opinion attaches to the Governor’s articulation of what is viewed as an impermissible purpose, this hardly supports the proposition that permissible purposes cannot be considered by a court unless they were somehow identified by the legislature as goals of the statute. The plurality opinion in fact examines the asserted safety purpose of the Iowa statute at some length. Indeed, Justice BRENNAN criticizes the plurality for examining the safety purpose and “disregarding the intention of Iowa’s lawmakers,” ante, at 681.
Finally, Justice BRenNan’s statement that we have strayed from what he regards as the true faith in our recent decision in United States Railroad Retirement Board v. Fritz, 449 U. S. 166 (1980), albeit over his vigorous dissent, does not aid his argument. His dissent, while undoubtedly vigorous, was not sufficiently persuasive to deter six Members of the Court from joining that opinion.
Consolidated was a plaintiff in Raymond as well as this case.