The Dallas Independent School District (DISD), the eighth largest urban school district in the country, has been the subject of desegregation litigation for over twenty years.1 In 1975, a panel of this court remanded the case to the district court with instructions that a plan be implemented that would effectively desegregate the school system. Tasby v. Estes, 517 F.2d 92 (5th Cir.), cert. denied, 423 U.S. 939, 96 S.Ct. 299, 46 L.Ed.2d 271 (1975). On remand, a new school desegregation plan was adopted by the district court. Tasby v. Estes, 412 F.Supp. 1192 (N.D.Tex. 1976). In these consolidated appeals, the NAACP, intervenors in the desegregation case2, primarily challenge the student assignment portion of the district court’s order; this will be referred to as the main appeal. The NAACP claims that the student assignment plan cannot pass constitutional muster because of the large number of one-race schools it establishes. The plan divides the DISD into six subdistricts, one of which is nearly all black and contains only one-race schools.3 In the other five subdistricts, containing some 160 schools, approximately fifty are still essentially one-race schools. Two other matters concerning the DISD are also before this court: the exclusion of the Highland Park Independent School District from the district court’s desegregation plan4 and the acquisition and sale of certain school sites by the DISD.5

I. The Main Appeal

A detailed description of the proceedings in this complex litigation prior to 1975 can *1013be found in the opinion of the previous panel, which is reported at 517 F.2d 92 (5th Cir.), cert. denied, 423 U.S. 939, 96 S.Ct. 299, 46 L.Ed.2d 271 (1975). That panel disapproved the district court’s 1971 plan, which sought to eliminate the vestiges of a dual school system in the DISD, and remanded the case for the formulation of a more effective student assignment plan.

Since 1971, substantial changes have occurred in the DISD. The residential patterns of Dallas have shifted; many areas are now naturally integrated. What was formerly a majority Anglo system has become a predominantly minority one, although the population of the city of Dallas remains majority Anglo.6 As the district court recognized in fashioning the plan now before us, there may be special considerations involved in devising a school desegregation plan in an urban area with a predominantly minority enrollment that may justify the maintenance of some one-race schools. 412 F.Supp. at 1195-1199. See Calhoun v. Cook, 522 F.2d 717 (5th Cir.), rehearing denied, 525 F.2d 1203 (5th Cir. 1975) (discussing similar developments in Atlanta, Georgia).

In devising its plan, the district court considered numerous proposals to desegregate the school system. Plans were submitted by the original plaintiffs; the NAACP; the DISD; Dr. Joseph A. Hall, a court-appointed expert; and the Education Task Force of the Dallas Alliance, a triethnic group and amicus curiae in this suit.7 After developing a voluminous record and holding hearings for over a month on the feasibility and effectiveness of these proposals, the district judge drew a comprehensive plan dealing, inter alia, with special programs, transportation, discipline, facilities, personnel, and an accountability system, as well as student assignments. 412 F.Supp. at 1195, 1212-21. We find it necessary to remand again the student assignment portion of the plan for further consideration. On remand, the district court should reconsider the other provisions of its plan in the light of the relief it ultimately orders.8

The order under review calls for the creation of six subdistricts, generally reflecting the geographical sections of the DISD, for student assignment purposes. Four of these subdistricts, Southwest, Northwest, Northeast, and Southeast, have approximately the racial makeup, plus or minus five percent, of the DISD as a whole. The other two subdistricts each contain a predominant ethnic group. Seagoville, geographically isolated from the rest of the DISD, has an approximately eighty-two percent Anglo enrollment and is the only predominantly Anglo subdistrict. East Oak Cliff, bounded by the Trinity River bottom on one side and by Interstate 35 on the other, is approximately ninety-eight percent black.

The district court order provides for uniform grade configurations throughout the DISD: kindergarten through third grades (K-3) Early Childhood Education Centers, fourth through sixth grades (4-6) Intermediate Schools, seventh and eighth grades (7-8) Middle Schools, and ninth through twelfth grades (9-12) High Schools.9 Wherever possible, present student assign*1014ments are retained in “naturally integrated” areas. Students in the K-3 Early Childhood Education Centers remain in their neighborhood schools.10 In the areas that are not naturally integrated, students in grades 4-8, the Intermediate and Middle Schools, are assigned to centrally located schools. High school students are assigned to their traditional neighborhood schools.

Various programs to increase the desegregation of the DISD’s schools are to be implemented. Majority-to-minority transfers are permitted at all grade levels.11 Present magnet high schools and magnet comprehensive high schools12 are to be maintained and new ones are to be established. The goal is the institution of magnet 9-12 schools throughout the DISD. 412 F.Supp. at 1205.

The DISD acknowledges that the creation of the all black East Oak Cliff subdistrict and the existence of a substantial number of one-race schools militate against the finding of a unitary school system. It contends, however, that this is the only feasible plan in light of natural boundaries and “white flight.” The district court was instructed in the opinion of the prior panel to consider the techniques for desegregation approved by the Supreme Court in Swann v. Charlotte-Mecklenburg Board of Education, 402 U.S. 1, 91 S.Ct. 1267, 28 L.Ed.2d 554 (1971). We cannot properly review any student assignment plan that leaves many schools in a system one race without specific findings by the district court as to the feasibility of these techniques. Davis v. East Baton Rouge Parish School Board, 570 F.2d 1260 (5th Cir. 1978). There are no adequate time-and-distance studies in the record in this case. Consequently, we have no méans of determining whether the natural boundaries and traffic considerations preclude either the pairing and clustering of schools or the use of transportation to eliminate the large number of one-race schools still existing. See Mims v. Duval County School Board, 329 F.Supp. 123, 133-34 (M.D.Fla.) aff’d 447 F.2d 1330 (5th Cir. 1971).

Of particular concern are the high schools that are one race. Although students in the 4-8 grade configurations are transported within each subdistrict to centrally located schools to effect desegregation, the district court’s order leaves high school students in the neighborhood schools. Within three of the four integrated subdistricts 13, this results in high schools that are still one-race schools.14 The district court is *1015again directed to evaluate the feasibility of adopting the Swann desegregation tools for these schools and to reevaluate the effectiveness of the magnet school concept.15 If the district court determines that the utilization of pairing, clustering, or the other desegregation tools is not practicable in the DISD, then the district court must make specific findings to that effect.

The district court’s current desegregation plan requires the DISD to provide transportation for students who are reassigned to a new attendance zone or who choose to attend a magnet school. 412 F.Supp. at 1218. A similar provision was not made for those students who choose the majority-to-minority transfer option. This omission was error by the district court. The school board, not the students or their parents, must assume the burden of transporting the students. Swann, 402 U.S. at 26-27, 91 S.Ct. at 1281. On remand, the district court is directed to include the majority-to-minority transfer option in the transportation provision of the plan finally adopted.

II. The Highland Park Independent School District

After the prior panel remanded this case to the district court, the plaintiffs joined seven independent suburban school districts in the Dallas area as defendants.16 The plaintiffs alleged that these school districts retained vestiges of dual school systems and that they joined with the DISD in utilizing a student transfer procedure that aided the DISD in maintaining segregated schools. On the basis of this allegedly unlawful procedure, the plaintiffs sought to have the suburban school districts included in the DISD desegregation plan.

The plaintiffs moved for the voluntary dismissal of all but one of the suburban school districts, and the district court dismissed them without prejudice. The remaining school district, Highland Park Independent School District, was dismissed with prejudice by the district court after an evidentiary hearing. Tasby v. Estes, 412 F.Supp. 1185 (N.D.Tex. 1975).

The Highland Park Independent School District was created in 1914. It generally serves as the school district for the cities of Highland Park and University Park, although its boundaries are not coterminous with those of the cities. At the time of its inception, the Highland Park school system was outside the city limits of Dallas; now, the city of Dallas completely surrounds Highland Park and University Park. The school system is comprised of six schools,17 and the current enrollment has stabilized at approximately 4,600 students, all of whom are Anglo. The DISD has approximately thirty times more students than the Highland Park system.

Prior to 1958, the Highland Park System conformed with Texas law and segregated school children by race.18 In order to accomplish this, the few black school children residing within the school district were transported to the DISD, with their tuition being paid by the Highland Park school system.19 Some Anglo students were allowed to transfer into the Highland Park system until 1971, primarily because either *1016they resided in the cities of Highland Park or University Park or they had moved out of the school district and were being allowed to continue their education in the system. 412 F.Supp. at 1190-91.

The district court found that the Highland Park Independent School District has not maintained a policy of school segregation since 1958. This finding is supported by the record and, as it is not clearly erroneous, is accepted by this court. Fed.R.Civ.P. 52(a). Given this twenty year history of nondiscrimination and the negligible effect that the system’s prior policy of segregation had on the DISD or its own system, we find that the district court did not err in refusing to include the Highland Park Independent School District in the student assignment plan for the DISD. See Dayton Board of Education v. Brinkman, 433 U.S. 406, 97 S.Ct. 2766, 2775-76, 53 L.Ed.2d 851 (1977); Milliken v. Bradley, 418 U.S. 717, 94 S.Ct. 3112, 41 L.Ed.2d 1069 (1974).

III. The Acquisition and Sale of School Sites.

On October 11, 1976, following the implementation of the district court’s plan to desegregate DISD, the Board of Education of the DISD20 unanimously resolved that an election be called to authorize the Board to issue $80,000,000 in bonds for school site acquisitions, construction, and equipment. The bond issue passed overwhelmingly in all subdistricts on December 11, 1976.

The prior panel had directed the district court

to evaluate all of the site acquisition, school construction and facility abandonment plans put forward by the DISD in light of the impact which these undertakings will have upon the disestablishment of the dual school system. Only those projects which will foster the desegregation process should be approved by the district court and such approval should be given only after full hearing and after the making of findings of fact and conclusions of law regarding each such project.

517 F.2d at 110. The DISD submitted forty-two plans, including thirty-two site acquisitions and constructions and ten abandonments, to the district court on February 17, 1977, and a hearing was held on February 24. On March 2, the district court approved each of the plans. In appeal No. 77-1752, the NAACP questions the district court’s approval of two of these plans: the acquisition of the A. Harris Shopping Center for conversion into a school21 and the sale of one parcel of unimproved land. The shopping center and the land in question are both located in the East Oak Cliff sub-district.

The A. Harris Shopping Center site occupies twenty-eight acres of land, divided into two tracts by a street. There are 305,000 square feet of existing building space on the eighteen acre tract. The site was purchased by the DISD for approximately $1,800,000, an amount far below what it would cost the DISD to purchase twenty-eight acres and build comparable floor space.22 The DISD proposed an initial outlay of $500,000 for renovation of the existing structures, with an additional $1,000,000 to be spent over the next five years. 2d Supp.Record, vol. 1, at 29, 167, No. 77-1752.

The DISD’s plans for the shopping center complex include a K-12 school23, facilities *1017to provide a number of education services24, and facilities to provide social services25. There will also be traditional grade levels K-3, 4-6, 7-8, and 9-12. These different educational operations will be conducted as distinct facilities with separate administrations, teaching staffs, and physical education programs. The DISD anticipates that it will ultimately assign approximately 2,400 students to the traditional K-12 school units.

The crux of the NAACP’s argument about the shopping center site is that its location in East Oak Cliff, with an attendance zone that encompasses only East Oak Cliff schools, perpetuates school segregation in Dallas. Virtually all of the students to be assigned to the new school will be black. NAACP also raises questions concerning the combination of programs to be implemented in the shopping center site. One of the programs is to be a “metropolitan” school, an alternative school for “troubled” students, i. e., those students who experience difficulty in the more traditional school setting. Also raised as grounds for not converting the shopping center to educational use are the traffic problem because of its location near two freeways and the inferiority of the facilities.26

We defer to the DISD’s expertise in establishing suitable programs for the school children of Dallas. The long-range plans for the shopping center site include many valuable facets for the education of the community. The DISD has stated that the programs will be separated, the existing structures will be renovated, and unoccupied space will be converted to traditional recreational and playground space suitable for the various grade-level school units. We are remanding this case to the district court for further consideration of its student assignment plan; on remand, the district court is directed to consider assigning Anglo students to the new complex. As the DISD notes, the shopping center site is easily accessible to the entire city. 2d Supp. Record, vol. 1, at 30, No. 77-1752. Time- and-distance studies should emphasize the feasibility of transporting Anglo students to attend school there.

The unimproved land in question is located on the southern edge of East Oak Cliff, some twenty-five miles from the northern edge of the DISD. It is therefore isolated from the remaining Anglo students who do not reside in naturally integrated areas. The record also reflects that the site has poor access potential. Given these facts in the record, we find no error in the district court’s approval of the sale of this land.

The Concerned Citizens of Glenview, a corporation of parents of school children who will be assigned to the shopping center complex under the present student assignment plan, brought a separate action to enjoin construction and renovation of the A. Harris Shopping Center. On May 18, 1977, the district court held a hearing on the Concerned Citizens’ request for injunctive relief. At that hearing, the district judge ruled that this case should be dismissed on the basis of the doctrine of virtual representation, i. e., Concerned Citizens was in effect represented by the NAACP when the issue was presented in the Tasby case. The Concerned Citizens claims on appeal that the focus of its suit, that the shopping center facility will be inferior thereby denying the students equal protection of the *1018laws, is different from that of the NAACP, that the use of the shopping center will perpetuate a dual school system.

We have considered the adequacy of the proposed shopping center facility in connection with the NAACP’s appeal. Our disposition in that case renders moot the appeal of the Concerned Citizens of Glenview.

IV. Conclusion

In No. 76-1849, we REMAND the case to the district court for the formulation of a new student assignment plan and for findings to justify the maintenance of any one-race schools that may be a part of that plan. The district court is directed to include in its plan a majority-to-minority transfer option with adequate transportation. As for the remaining provisions of its order here under review, the district court is to reassess such provisions in light of the remedy it fashions with respect to school assignments. The district court’s exclusion of the Highland Park Independent School District from its desegregation plan for the DISD is AFFIRMED.

In No. 77-1752, the district court’s approval of the sale of the ten-acre parcel of land in East Oak Cliff and the acquisition of the A. Harris Shopping Center is AFFIRMED, with the proviso that the district court consider the feasibility of desegregating the new complex. The appeal in No. 77-2335 is DISMISSED as moot.