OPINION

Robinswood Community Club and a class comprised of its members (Robins-wood) appeal from the denial of a preliminary injunction to enjoin federal and state officials from completing construction of the Eastgate interchange on a segment of Interstate Highway Project 1-90 near Seattle, Washington. Robins-wood alleges noncompliance with section 102(2)(C) of the National Environmental Policy Act of 1969 (NEPA), 42 U.S.C. § 4332 (2)(C), the Federal-Aid Highway Act, 23 U.S.C. § 109 (b) and FHWA Policy and Procedure Memorandum (PPM) 20-8, 34 Fed.Reg. 728 (1969).

The design for the Eastgate interchange was conceived in 1962, though program and route approval by the Secretary of Transportation was not given until several years later. This controversy centers around the engineering design stage. 1

The State of Washington, pursuant to PPM 20-8, held numerous meetings with community groups to explain the Richards Road to Lake Sammamish segment of 1-90, of which the Eastgate interchange is an integral part. Comments and suggestions were solicited resulting in revisions to the state developed design. Several meetings were held in 1969 with representatives of the Robinswood Community Club. Based on the Club’s recommendations the design of the interchange was altered and the Club expressed its appreciation by a letter approving the revised design.

A combined corridor and highway design public hearing for the Richards Road to Lake Sammamish segment was held on July 29, 1969, in accordance with PPM 20-8 § 6(b). At the hearing, a report was submitted which dealt with 23 social, economic and environmental effects of the proposed segment. Although the subjects of noise, air and water pollution were treated in a cursory fashion in the report, affidavits in the record reveal that the ecological effects of the design were discussed at the hearing. Suggestions offered at the design hearing were incorporated into the final design which was submitted to and approved by the Secretary of Transportation on December 11, 1969.

In 1970, after final design approval by the federal government and absent any objection, the Washington State Department of Highways proceeded with detailed design, acquisition of right of way and preparation of contract plan documents.

Robinswood first sought injunctive relief supported by a single affidavit alleging irreparable harm on April 13, 1971. The motion was denied on August 27, 1971. Eight months later, during which the State of Washington let some $10,000,000 in construction contracts, Robinswood again sought a preliminary injunction, which was denied on April 21, 1972. The district judge concluded that since final design approval by the federal government had been given prior to the effective date of NEPA, an impact statement was not required. This appeal followed. We affirm.

To obtain a preliminary injunction Robinswood must satisfy at least two requirements: First, it must demonstrate a strong likelihood or reasonable certainty that it will prevail on the merits; second, it must show it will suffer irreparable injury if the injunction is not granted. Sierra Club v. Hickel, 433 F.2d 24, 33 (9th Cir. 1970), aff’d on other grounds, 405 U.S. 727 , 92 S.Ct. 1361 , 31 L.Ed.2d 636 (1972). The granting or denial of a motion for preliminary injunction rests within the sound discretion of the trial court. County of Santa Barbara v. Hickel, 426 F.2d 164, 168 (9th Cir. 1970). Accordingly, we must decide whether the district judge abused his discretion.

*1369 I. The National Environmental Policy Act of 1969

Section 102(2)(C) of NEPA requires an impact statement for major federal actions significantly affecting the quality of the human environment. Complications arise when a project such as we are concerned with here, straddles the effective date of NEPA, January 1, 1970.

The Council on Environmental Quality (CEQ), the watchdog organization created by NEPA, issued guidelines requiring all federal agencies to direct their efforts at meeting national environmental goals. Each agency was ordered to comply with section 102(2)(C) to the fullest extent possible. Specific reference was made to existing projects or programs:

36 Fed.Reg. 7727 (1971).

Each agency was entrusted with the responsiblity of developing its own formal procedures to identify instances where environmental impact statements were required. The procedures were to be consonant with the Council’s guidelines. Pursuant to this mandate, the Department of Transportation issued PPM 90-1 on August 24, 1971. Section 5b of the Memorandum, designating when a section 102(2)(C) statement shall be prepared for a highway segment, provides:

The district court ruled that PPM 90-1 § 5b did not require compliance with section 102(2)(C) because the Secretary of Transportation had given final design approval prior to the effective date of NEPA. The issue presented is whether the date of final design approval is the controlling criterion for determining the applicability of NEPA to ongoing highway projects.

Federal courts have frequently grappled with the question of the retrospective application of NEPA. Some courts have adopted the date of final design approval by the Secretary of Transportation as the peg date for the application of NEPA. Concerned Citizens of Marlboro v. Volpe, 459 F.2d 332, 335 (3d Cir. 1972); see Pennsylvania Environmental Council, Inc. v. Bartlett, 454 F.2d 613, 624 (3d Cir. 1971) (Secretary’s final approval). Other courts have focused on *1370 the degree of completeness of a federal highway project and denied retrospective application of section 102(2)(C) to projects where federal participation was virtually complete. Ragland v. Mueller, 460 F.2d 1196 (5th Cir. 1972). Still other courts have determined the application of section 102(2)(C) not solely on the basis of the date of final approval, but also on the basis of a number of factors including, among others, CEQ guidelines, extent of construction on the project, extent of public participation in the planning stages and likelihood of harm to the environment. E. g., Northside Tenants’ Rights Coalition v. Volpe, 346 F.Supp. 244 (E.D.Wis.1972); Indian Lookout Alliance v. Volpe, 345 F.Supp. 1167 (S.D.Iowa 1972), modified, 484 F.2d 11 (8th Cir. 1973); Conservation Society v. Volpe, 343 F.Supp. 761 (D.Vt.1972); Environmental Law Fund v. Volpe, 340 F.Supp. 1328 (N.D.Cal. 1972).

Although not faced with the issue in a case involving a highway project, we have already spoken on the general issue involved here in determining at what stage of development we can say a project is pre-NEPA. In San Francisco Tomorrow v. Romney, 472 F.2d 1021 (9th Cir. 1973), we analyzed the applicability of the Act in two urban renewal programs, both of which commenced prior to January 1, 1970. We held that section 102(2)(C) required that an environmental impact statement be filed in one case, but not in the other. The deciding factor was not whether buildings would be built or earth moved after the beginning date of the Act, but whether there were any further stages requiring major action by the government. That the government would later monitor the project was not a “major Federal action” pursuant to section 102(2)(C).

The same theory has application here. Once the engineering design stage is finalized, the plan, the implementation of which results in an impact on the environment, has been completed. Each house that is moved, each mound of dirt that is excavated, each ribbon of concrete that is laid has an impact on the environment, but that impact is determined by the plan already adopted. Of course, the government will have substantial participation in the project subsequent to January 1, 1970. But mere participation is not enough. The real question is whether the government’s continued participation constitutes "further major Federal actions having a significant effect on the environment . . . 36 Fed.Reg. 7727 (1971) (emphasis added). After final design approval, nothing further occurs which (1) is major and (2) has a significant effect on the environment other than what is contemplated by the approved design. This analysis is completely consistent with our holding in San Francisco Tomorrow ; indeed, a contrary holding would contravene its basic thrust.

We, therefore concur with the Secretary’s apparent interpretation that NEPA becomes applicable only when the final design approval occurs after January 1, 1970. PPM 90-1 § 5b. We hold that NEPA is not applicable when final design approval occurred prior to that date and the subsequent participation does no more than carry out the approved design.

Admittedly, the cutoff line could be drawn anywhere. Every major federal action has at least a conception and an execution; every execution may adversely affect the environment. But governments, just as ordinary citizens, have a need for definiteness in the conduct of their affairs. In this sense, we view the applicability of NEPA to a project begun prior to its effective date as similar to that of a statute of limitations. Some rights will be saved but others will be lost when we apply an arbitrary standard to an ongoing series of events. Nevertheless, the standard must be applied and we believe that the point of final approval is the logical place. This makes a definitive point which can be appropriately called “major Federal action.”

*1371 II. The Federal-Aid Highway Act

Robinswood contends that 23 U.S.C. § 109 (b) 2 was not complied with because the geometric and construction standards for the Eastgate interchange were not adequate to meet anticipated traffic projections for the twenty-year period commencing on the date of federal approval. Robinswood produced an engineering study which purported to show that current traffic flow is at the projected 1990 level. Based on the record before us we cannot agree. The State of Washington made a traffic study which indicated compliance with the mandates of section 109(b). We are aware that such projections are rarely entirely accurate and that data can be contorted to produce a desired statistic. Nonetheless, the state traffic study was clearly admissible into evidence and we cannot say on the record before us that the trial judge could not rely on that report. His findings in regard to the report are not clearly erroneous.

III. FHWA Policy and Procedure Memorandum 20-8

Robinswood alleges that because of certain deficiencies in the combined corridor and highway design hearing on July 29, 1969, a new design hearing is required. The deficiencies allegedly involved the failure to consider 23 social, economic and environmental factors in approving the location of the Eastgate interchange. We disagree. The record reveals that not only was a report prepared by the State of Washington concerning the 23 factors but also the factors were discussed at the design hearing. This was sufficient for compliance with PPM 20-8.

Robinswood neither demonstrated a strong likelihood that it would prevail on the merits nor irreparable injury. Therefore, the district judge did not abuse his discreton in denying the injunction.

■Affirmed.

. This circuit recently, examined the five stages in the construction of a federally financed highway in Lathan v. Volpe, 455 F.2d 1111 (9th Cir. 1971). The stages are: ixrogram, routing, engineering design, right-of-way acquisition and actual construction.

. 23 U.S.C. § 109 (b) provides in pertinent part: