As this case demonstrates, a school board’s adoption of a geographic zoning system instead of a “freedom of choice” system is not a guarantee of effective desegregation. “Geographic zoning, like any other attendance plan adopted by a school board in this Circuit, is acceptable only if it tends to disestablish rather than reinforce the dual system of segregated schools.” United States v. Greenwood Municipal Separate School District, 5 Cir. 1968, 406 F.2d 1086. In Davis v. Board of School Commissioners of Mobile County, 5 Cir. 1968, 393 F.2d 690, we recognized that in many instances geographic zoning offers “administrative improvement and *684greater desegregation” but required the Board to make a new effort to draw zone lines “on a nonracial basis so that the attendance-area plan will promote desegregation rather than perpetuate segregation”.
Here the district court found that the school board acted in good faith. But good faith does not excuse a board’s non-compliance with its affirmative duty to liquidate the dual system. Good faith is relevant only as a necessary ingredient of an acceptable desegregation plan.
In 1964, under court order, the Clarksdale Municipal Separate School District of Mississippi redrew its attendance zones and adopted the geographic zoning system as the basis for desegregating its schools. In the fall of that year, not a single child in Clarksdale was enrolled in any school with members of the other race. Again, for the spring semester of the 1964-65 year, not a single child was enrolled in a school attended by children of the other race. When this case was tried in April 1965, 2800 Negro pupils attended the five “Negro” schools in Clarksdale and 2100 white children attended white schools along with two Negro girls who had transferred to the white high school to obtain a course, Latin, not available in the Negro high school.
In Jefferson this Court considered freedom of choice plans in operation in Jackson, Biloxi, and Leake County, Mississippi, and in other parish and county school districts throughout this circuit. United States v. Jefferson County Board of Education, 5 Cir. 1966, 372 F.2d 836, adopted en banc, 380 F.2d 385, cert. denied sub nom. Caddo Parish School Board v. United States, 1967, 389 U.S. 840, 88 S.Ct. 67, 19 L.Ed.2d 103. Much of what we said in our opinion in that ease applies to any school desegregation plan. We held that school officials have an “affirmative duty” to reorganize their schools into “an integrated, unitary school system in which there are no Negro schools and no white schools — just schools”. 380 F.2d at 389. We recognized that freedom-of-choice plans have “serious shortcomings” and suggested a detailed order to attempt to overcome some of the shortcomings. We pointed out, “The only school desegregation plan that meets constitutional standards is one that works.” (Original emphasis.) 372 F.2d at 847. Recently, the Supreme Court has underscored a school board’s “affirmative duty” today “to come forward with a plan that promises realistically to work, and promises realistically to work now”. (Original emphasis.) Green v. County School Board of New Kent County, Virginia, 1968, 391 U.S. 430, 88 S.Ct. 1689, 20 L.Ed.2d 716. In Green the Court found that the freedom of choice plan used in New Kent County was ineffective and suggested alternatives, including zoning, that might bring about a “speedier and more effective conversion [of the dual system] to a unitary, nonracial school system”.1
A geographic system of allocating students to schools is a pragmatic solution that avoids the “haphazard”2 element in administering a freedom of choice plan based on the individual pupil’s considered or perhaps capricious selection of a school to attend. A district court in Louisiana recently observed:
If this Court must pick a method of assigning students to schools within *685a particular school district, barring very unusual circumstances, we could imagine no method more inappropriate, more unreasonable, more needlessly wasteful in every respect, than the so-called “free-choice” system. Moses v. Washington Parish School Board, E.D.La. 1967, 276 F.Supp. 834.
Historically, a compulsory attendance zone system almost invariably prevailed in the school districts in this circuit3 — until Brown4 ordered an end to school segregation. But an attendance zone plan also may fail to work. When a particular plan does not succeed in converting a dual system into a unitary system, the school board must find ways for the plan to succeed.
The plaintiffs contend that the attendance zone plan in Clarksdale extends promises it cannot fulfill. They allege also that the zones were drawn for the purpose and have had the effect of maintaining the racial identity of each formerly white and formerly Negro school.
The plaintiffs raised additional issues in the district court. One concerned the speed of desegregation to take place in Clarksdale. This issue, of course, is settled: The time is now. As Green puts it, “delays are no longer tolerable * * * [and] a plan that at this late date fails to provide meaningful assurance of prompt and effective disestablishment of a dual system is also intolerable’. 391 U.S. at 438, 88 S.Ct. at 1694. Other issues in the district court involved the qualitative differences between “white” schools and “Negro” schools.5 Jefferson tried to put an end to such differences by requiring integration “lock, stock, and barrel”: faculty and staff (part VIII), services, facilities, extracurricular activities and programs (part V), and school equalization (part VI).6 Similarly, Green requires “dismantling” of the state-imposed dual system “root and branch”.
The issue on this appeal centers on the geographic zones established by the school board. The record clearly establishes that all pupils living in each zone are required to attend the school in that zone. As we recognized in Jefferson, however, such factors as residential patterns, the mushrooming of private schools, and a minority-to-majority transfer policy may bring about a school attended exclusively or almost exclusively by students of one race, although the zone originally etched out to supply students for that school may have been racially mixed.
Clarksdale is bisected from the northeast to the southwest by a main line of the Illinois Central Railroad. Commercial and Industrial establishments lie adjacent to both the northern and southern side of the railroad tracks, accentuating the division of the residential areas of the town. Elevated tracks on an embankment add to this division.
Clarksdale is also bisected by the Sunflower River running north-south through the city. The southern half of the city is divided by another line of railroad tracks running north-south, which is built on the same grade as *686the surrounding lands. There are four underpasses and one grade crossing transversing the embanked railroad tracks. Only one of these underpasses is west of the Sunflower River, and it is next to the river. The central business district is in the northern half of Clarksdale, and east of the Sunflower River. Two bridges span the river in both the northern and southern sections of the community.
Traditionally, most Negro residents in the city have lived south of the Illinois Central tracks, while the great majority of the white residents have lived north of the tracks. Under the school board’s proposed attendance-zone plan, no school child will cross those tracks. The result was obvious from the beginning-: the zoning could produce only token desegregation.
The plaintiffs attempted to prove that the purpose behind the board’s drawing of the present zone lines is to perpetuate a dual, segregated school system in Clarksdale.7 They allege that certain pockets of Negro residences north of the tracks were purposefully removed through deannexation, purchase, or urban renewal by public authorities so that no Negroes would reside in the attendance zones of the northern half of Clarksdale.8 We agree with the district *687court that evidence on this issue is irrelevant, but not for the reasons supporting the district judge’s conclusion. It is irrelevant because the ultimate inquiry is not whether the school board has found some rational basis for its action, but whether the board is fulfilling its duty to take affirmative steps, spelled out in Jefferson and fortified by Green, to find realistic measures that will transform its formerly de jure dual segregated school system into a “unitary, nonracial system of public education”.
In Monroe v. Board of Commissioners of the City of Jackson, 1968, 391 U.S. 450, 88 S.Ct. 1700, 20 L.Ed.2d 733, a companion case to Green, the school board for the city of Jackson, Tennessee, established a plan involving attendance zones drawn according to certain established criteria and containing a free-transfer provision. The schools of Jackson retained their racial identity, with only token integration. The Supreme Court, focusing on the free-transfer aspect of the plan, observed:
Plainly, the plan does not meet respondent’s “affirmative duty to take whatever steps might be necessary to convert to a unitary system in which racial discrimination would be eliminated root and branch.” Green v. County School Board, supra, 391 U.S. at p. 437-438, 88 S.Ct. at 1694. Only by dismantling the state-imposed dual system can that end be achieved. And manifestly, that end has not been achieved here, nor does the plan approved by the lower courts for the junior high schools promise meaningful progress towards doing so. * * * That the Board has chosen to adopt a method achieving minimal disruption of the old pattern is evident from its long delay in making any effort whatsoever to desegregate * * *.
The Court concluded that “free transfer”, like “freedom of choice”, can have no place in a desegregated plan * * “if it cannot be shown that such a plan will further rather than delay conversion to a unitary, nonracial, nondiscriminatory school system * *
In Clarksdale only two elementary schools are likely to be attended by children of both races. All other schools will be “white” or “Negro”, corresponding to their status before the present plan was adopted. It is evident then that the board here has not fulfilled its duty, spelled out in Green, “to come forward with a plan that promises realistically to work, and promises realistically to work now.”
The basic criteria the school board used in this case were rational: (1) maximum utilization of school buildings; (2) density of population; (3) proximity of pupils to schools; (4) natural boundaries; and (5) welfare of students. This fifth criterion requires consideration of attractive nuisances and health hazards. The presence of public transportation for school children would be relevant to the weight to be given the proximity criterion. By the same token, natural boundaries, such as the tax districts used in Moses v. Washington Parish, are not to be confused with “historical” boundaries, i. e. those that have historically separated white and Negro residential areas.9 Finally, safety haz*688ards may be applicable to students of various ages in differing degrees, and the history of community action vis-avis those hazards should be taken into consideration.10 No one doubts the relevance of such criteria. But a relationship otherwise rational may be insufficient in itself to meet constitutional standards— if its effect is to freeze-in past discrimination. For example, a rational relationship exists between literacy or citizenship tests (fairly administered) and the right to vote. But we enjoin the use of such tests when they freeze into a voters’ registration system the effects of past discrimination.
But there is a sixth basic criterion the Board did not use: promotion of desegregation. Jefferson, Stell, Davis, Braxton, Polk County, Carr, Bessemer, Adams, Graves and Greenwood, and other cases decided by this Court,11 and now Green v. County School Board of New Kent County, require school authorities to take affirmative action that will tend to eradicate all vestiges of the dual system. For example, given a choice of alternatives, a school board should draw zone lines, locate new schools, consolidate schools, change feeder patterns, and resort to other measures that will reduce the effect of past patterns tending to maintain segregation (or token desegregation). “Where the Board is under compulsion to desegregate the schools (1st Brown case, Brown v. Board of Education of Topeka, 347 U.S. 483, 74 S.Ct. 686, 98 L.Ed. 873) we do not think that drawing zone lines in such a manner as to disturb the people as little as possible is a proper factor in rezoning the schools.” Northcross v. Board of Education of City of Memphis, 6 Cir. 1964, 333 F.2d 661. In Davis v. Board of School Commissioners of Mobile, Alabama, 5 Cir. 1968, 393 F.2d 690 we considered it our primary concern “to see that attendance zones in the urban areas * * * [are] devised so as to create a unitary racially nondiscriminatory system.” We held:
We therefore accept the board’s policy decision in this regard but insist on a survey and new effort to draw zone lines on a nonracial basis so that the attendance-area plan will promote desegregation rather than perpetuate segregation. It is intended that attendance areas be designed according to strictly objective criteria with the caveat that a conscious effort should be made to move boundary lines and change feeder patterns which tend to preserve segregation. 393 F.2d at 694.
As stated by the U. S. Dept, of Health, Education, and Welfare, in its Policies on Elementary and Secondary School Com*689pliance with Title VI of the Civil Rights Act of 1964 (March 1968):
School systems are responsible for assuring that to the extent it is administratively feasible, the zone boundaries do not perpetuate any vestiges of a dual school structure and that among the various attendance zone arrangements which are possible, it establishes the one which best promotes elimination of its dual school structure.
Bearing in mind the historical background of state-compelled educational segregation, consideration of race may be necessary to provide an adequate remedy that will erase or minimize the effects of the dual school system. “The court has not merely the power but the duty to render a decree which will so far as possible eliminate the discriminatory effects of the past as well as bar like discrimination in the future.” United States v. State of Louisiana, 1965, 380 U.S. 145, 154, 85 S.Ct. 817, 822, 13 L.Ed.2d 709. A school board’s zoning policy may appear to be neutral but in fact tend to retard desegregation because it binds pupils to custom-segregated neighborhoods. In this situation, the board’s failure to take corrective action amounts to the State’s giving official sanction to continued school segregation, contrary to the mandate of this Court and of the Supreme Court.12 Black nationalists and white racists notwithstanding, school integration is relevant: It is an educational objective as well as a constitutional imperative.
At the time this case was tried Clarksdale still had segregated schools. A long time has' elapsed since the trial, partly because this Court delayed rendering its decision in order to obtain further enlightenment from the Supreme Court on the subject of attendance zones plans as against freedom of choice plans. In view of the delay, we believe that the interests of justice require that the case be remanded for a hearing to determine the effectiveness of the Clarksdale plan in today’s factual setting and in the light of Green and other decisions of the Supreme Court and of this Court. The Board should bear in mind that it bears the burden of proving that its existing plan of desegregation is adequate now “to convert [the dual system] to a unitary system in which racial discrimination would be eliminated root and branch”. If the plan does not promise “realistically to work now”, the Board bears the burden of taking corrective action. An effective plan should produce desegregated faculties, staff, facilities, transportation, and school activites (such as athletics) along with integrated student bodies. If there are still all-Negro schools, or only a small fraction of Negroes enrolled in white schools, or no substantial integration of faculties and school activities then, as a matter of law, the existing plan fails to meet constitutional standards as established in Green and its companion cases. The board should consider redrawing its attendance-zone boundaries, incorporating a majority-to-minority transfer provision in its plan,13 closing all-Negro *690schools, consolidating and pairing schools, rotating principals, and taking other measures to overcome the defects of the present system. As to its attendance zones,
zone boundaries or feeder patterns designed or used to perpetuate or promote segregation shall be discontinued, and such zone lines shall be redrawn, wherever feasible, to maximize desegregation or eliminate segregation. No zone boundaries or feeder patterns which maintain what is essentially a segregated school structure shall be used. Braxton v. Board of Public Instruction of Duval County, M.D.Fla. 1967, F.Supp.
Accordingly, we remand this case to the district court for entry of a judgment or further proceedings consistent with this opinion.
. The court carefully stated, “Although the general experience under ‘freedom of choice’ to date has been such as to indicate its ineffectiveness as a tool of desegregation, there may well be instances in which it can serve as an effective device. Where it offers real promise of aiding a desegregation program to effectuate conversion of a state-imposed dual system to a unitary, nonracial system there might be no objection to allowing such a device to prove itself in operation.” Green v. School Board of New Kent County, 391 U.S. at 440, 88 S.Ct. at 1695. In areas where residential segregation is substantial, freedom of choice or free transfer plans may aid desegregation.
. See Singleton v. Jackson Municipal Separate School District, 5 Cir. 1966, 355 F.2d 865, 871.
. See Moses v. Washington Parish School Board, E.D.La.1967, 276 F.Supp. 884. See also Meador, The Constitution and the Assignment of Pupils to Public Schools, 45 Va.L.Rev. 517 (1959).
. Brown v. Board of Education (Brown I), 1954, 347 U.S. 483, 74 S.Ct. 636, 98 L.Ed. 873; Brown II, 1955, 349 U.S. 294, 75 S.Ct. 753, 99 L.Ed. 1083.
. The order of the district court corrected a number of deficiencies in the administration of schools by providing for equalization of curricula, teacher-salary scales, teacher-pupil ratios, and of per pupil expenditures for all schools of each level (elementary, junior high, and high schools). United States v. Bessemer Board of Education, 5 Cir. 1968, 396 F.2d 44; Moses v. Washington Parish, E.D.La.1967, 276 F.Supp. 834, n. 17; HEW Guidelines § 9. The court found merit in the appellants’ complaint that teachers were segregated but held that, because of teacher contracts having been signed for the 1965-66 year, faculty desegregation should be temporarily deferred.
. See especially United States v. Bessemer Board of Education, 5 Cir. 1968, 396 F.2d 44.
. A zoning ordinance, enacted in July 1964 by the City of Clarksdale, de-annexed the property on East Second Street where the Negroes lived; the City and County purchased and demolished the homes located near the County Jail; and the City purchased and demolished the homes in Tuxedo Park, after annexing adjoining territories containing white residences. The Board denies any knowledge of the City and County action, and city officials maintain that the ordinance was not intended to affect school desegregation.
. The Higgins High School, containing all the Negro pupils in grades 7-12, is located south of these tracks, while the high schools containing all the white public high school pupils are located north of the tracks. Por elementary schools, Oliver, Hall, Washington and Riverton, containing all the Negro elementary pupils, are located south of the Illinois Central’s tracks. Three of the four elementary schools serving white pupils are located north of the tracks. The fourth elementary school, Eliza Clark, is located in a white residential section south of the tracks. Based on Board statistics provided in March 1965, 865 Negro high school pupils, all but two of the total eligible to attend high school, live south of the Illinois tracks attend Higgins, and if the Board has its way, will continue at Higgins. The effect of zoning one white and four Negro elementary schools located south of the Illinois Central tracks is that all Negroes will be assigned to schools traditionally serving Negro pupils and the great majority of white pupils will be assigned to the white Eliza Clark School. The three remaining white elementary schools located north of the Illinois Central tracks serve only pupils living north of the tracks. New if any of these students are Negroes. The Board estimated that in December 1964 only one Negro elementary school child was eligible by reason of residence to attend an elementary school now serving only white pupils. The district court approved the high school zones and the elementary zones located north of the Illinois Central tracks, adding requirements that all school facilities be equalized and that students seeking courses not offered in their assigned schools be given the right to transfer to schools where such courses are offered. The order temporarily approved the school zones located south of the Illinois Central tracks, but required reconsideration of these zones by the board and a resubmission of zones “predicated on efficient utilization of available school facilities on a racially nondiscriminatory basis in accordance with sound education princples”. The order further provided that, notwithstanding the elementary sub-districts located north of the Illinois Central tracks had been approved, the Board was free to revise these boundaries if this was necessary to accommodate changes in the elementary attendance zones located south of the Illinois Central tracks. The order awarded costs to appellants and retained jurisdiction of the case for additional orders which might become necessary or appropriate. In October 1965 the Board submitted its revised plan for the elementary attendance zones located south of the Illinois Central tracks. The sole change recommended was that the zone line dividing the white Eliza Clark school from the Negro Myrtle Hall school be eradicated and that, effective in September 1966 all first and *687second grade pupils in the combined zone be assigned to the Eliza Clark school and all pupils in grades three through six be assigned to the Myrtle Hall school. Appellants promptly filed objections to the revised plan, contending that there was no greater justification for retaining the zone lines of the other elementary schools and that, while the eradication of the line between the Myrtle Hall and Eliza Clark zones appeared to have advantages from an educational and desegregational standpoint, the practical effect of assigning the 115 white children from Eliza Clark with the approximate 415 Negro pupils from Myrtle Hall would be that white parents would refuse to send their children to the school and would move their residences to areas north of the Illinois Central tracks where, as the evidence shows, Negroes could not obtain housing.
. The school board’s original plan would have contained an irregularly drawn boundary surrounding the only all-white residential area south of the railroad tracks. This boundary would have zig*688¡sagged and followed unpaved roads; in sum, it would have cut between the white and neighboring Negro residential areas. The district court disapproved this zone, for obvious reasons.
. For example, while the use as a boundary of the elevated railroad tracks in Clarksdale would appear reasonable, such appearance must be measured against the past history of school children crossing those tracks to go to a school for their particular race. Having disregarded the tracks as impediments in order to maintain the racial purity of its schools, the school board cannot turn around and consider the tracks impenetrable when doing so will perpetuate that former racial purity. See United States v. State of Louisiana, E.D.La.1963, 225 F.Supp. 353, aff’d 380 U.S. 145, 85 S.Ct. 817, 13 L.Ed.2d 709; United States v. State of Mississippi, S.D.Miss.1964, 229 F.Supp. 925, rev’d 380 U.S. 128, 85 S.Ct. 808, 13 L.Ed.2d 717.
. Board of Public Instruction Duval County, Florida v. Braxton, 5 Cir. 1968, 402 F.2d 900; Stell v. Board of Public Education for the City of Savannah and the County of Chatham, 5 Cir. 1967, 387 F.2d 486; United States v. Board of Public Instruction of Polk County, Fla., 5 Cir. 1968, 395 F.2d 66; Montgomery Board of Education v. Carr, 5 Cir. 1968, 400 F.2d 1; United States v. Bessemer Board of Education, 5 Cir. 1968, 396 F.2d 44; Adams v. Mathews, 5 Cir. 1968, 403 F.2d 181; Graves v. Walton County Board of Education, 5 Cir. 1968, 403 F.2d 184. Jefferson, Davis and Greenwood are cited in the body of this opinion.
. “The impact [of segregation] is greater when it has the sanction of the law; for the policy of separating the races is usually interpreted as denoting the inferiority of the negro group.” Brown I, 347 U.S. at 494, 74 S.Ct. at 691. See Strauder v. State of West Virginia, 1880, 100 U.S. 303, 25 L.Ed. 664. See also United States v. School District 151 of Cook County, Illinois, 7 Cir. 1968, 404 F.2d 1125, in which the Seventh Circuit distinguished Bell v. School City of Gary, 7 Cir. 1963, 324 F.2d 209, followed by Deal v. Cincinnati Board of Education, 6 Cir. 1966, 369 F.2d 55 and Downs v. Board of Education, 10 Cir. 1964, 336 F.2d 988 on the ground that they dealt with “innocently arrived at de facto segregation with ‘no intention or purpose’ to segregate Negro pupils from White”. The dissenting opinion here cites with approval Bell, Deal and Downs.
. “If school officials in any district should find that their district still has segregated faculties and schools or only token integration, their affirmative duty to take corrective action requires them to *690try an alternative to a freedom of choice plan, such as a geographic-attendance plan, a combination of the two, the Princeton Plan, or some other acceptable substitute, perhaps aided by an educational park.” Jefferson I, 372 F.2d at 895-896.