I respectfully dissent.
There is no substantial evidence showing that parking needs, which will be inexorably generated by the massive convention center project, can be mitigated without construction of additional parking facilities. Therefore, construction of additional parking facilities is a direct, inevitable effect of the project, a conclusion which (given the size and location of the project) should come as no surprise to anyone. Yet no environmental consideration was given to the inevitable effects of constructing additional parking facilities.
The environmental impact report (EIR) did not pretend there were no parking problems. Rather, the EIR acknowledged serious parking problems and proposed a “menu” of mitigation measures to meet the demand for 2,621 spaces. The question is whether there was substantial evidence, as required by California Environmental Quality Act (CEQA), supporting the city council’s conclusion that the documented adverse environmental impacts of parking had been mitigated to a point of insubstantiality. The only mitigation measures that are relevant are those expressly found and adopted by the city council (City Council):
1. Promote regional/national conventions;
2. Provide satellite parking;
3. Promote alternative transportation modes for attendees;
4. Promote alternative transportation modes for existing area employees and visitors;
5. Construct additional parking.
Even assuming the parking reduction measures adopted by the City Council are supported by substantial evidence showing a reduction of parking problems to insignificance, the possible adverse effects of some of the mitigation measures (construction/expansion of additional parking, satellite parking, and promotion of national/regional conventions) should have been considered in the EIR. (Cal. Code Regs., tit. 14 (Guidelines) §§ 15064, subd. (d),1 15126, subd. (c).2
*1041Here, the effects of the mitigation measures were not discussed at all. There is no discussion of possible adverse effects of building additional parking facilities or expanding existing facilities. The City does not argue that it sufficiently discussed the adverse impacts of mitigation measures. Rather, the City’s position is that it was not possible or necessary to do so at this stage, because until a definite site was set, the City could not determine which mitigation measure would be selected or the size/location of new or expanded parking facilities.
The City’s argument is not valid. Based on the evidence before the City Council, it was clear that the fifth option (construct additional parking) would have to be chosen, because the other four mitigation measures combined are insufficient to meet the parking demand. Thus, disregarding the option of constructing new parking, the City’s projections show that only 1,070 spaces can be provided by two of the remaining four mitigation measures: promotion of alternative transportation for office workers (720 spaces) and the provision of satellite parking (350 spaces). Apart from the problem that these figures are unsupported by any evidence, the City is still left with an unmet demand of more than 1,500 parking spaces. There do not appear to be any specific figures in the EIR for the projected success of the other two mitigation measures: promoting alternative transportation for convention center attendees and promoting regional/national conventions.3 Therefore, construction of additional spaces is not merely an option but is a reasonably foreseeable and significant action that should have been addressed in the EIR in accordance with the Guidelines and the requirement that the EIR “must include an analysis of the environmental effects of future expansion or other action if: (1) it is a reasonably foreseeable consequence of the initial project; and (2) the future expansion or action will be significant in that it will likely change the scope or nature of the initial project or its environmental effects.” (Laurel Heights Improvement Assn. v. *1042Regents of University of California (1988) 47 Cal.3d 376, 396 [253 Cal.Rptr. 426, 764 P.2d 278].)
As to construction of new parking spaces, the EIR describes a downtown Sacramento parking study (Wilbur Smith Associates, Jan. 1988), which involves proposals to expand and develop three specific parking structures that would provide a total of 2,172 spaces.4 However, there is no discussion of the environmental effects of these proposals. Moreover, it does not appear that that study was prepared in connection with the convention center expansion, because the EIR states that at least two of those projects would be available to the general public but “could be designated for Convention Center use.”
On the record before us, the City’s conclusion in the EIR that the spaces identified in the Downtown Sacramento Parking Study “could be designated for convention center use” is nothing more than “[m]ere uncorroborated opinion,” which does not constitute substantial evidence. (Guidelines § 15384.)
The majority correctly conclude the trial court erroneously considered a subsequent outline of a draft EIR that was not before the City at the time the convention center expansion was approved. A court’s task is to determine “whether substantial evidence supports the agency’s determination. [Citations.]” (Laurel Heights, supra, 47 Cal.3d at p. 392, fn. 5, italics added.) Because the draft outline of a supplemental EIR has never been presented to the City Council, it cannot constitute evidence supporting the council’s determination.5 The document is simply a preliminary draft document, never circulated for public comment nor certified, which was lodged in the administrative record in an attempt to shore up what the City Council already did.6
*1043The traffic management plan does not help. It merely describes the kinds of efforts that may be made to promote alternative transportation for employees—carpooling, transit pass subsidies—but does not show how the parking needs identified in the EIR will be solved.
The record fails to contain any substantial evidence showing that the convention center expansion can be accomplished without construction of additional parking facilities. Yet, the City has failed to consider the environmental effects of the inevitable construction of parking spaces that will be required by the convention center expansion. This case sets a dangerous precedent because it allows proponents of major projects to defer a consideration of the environmental effects of constructing inevitably necessary parking structures. Once the project is approved, it can then be presented as a fait accompli in connection with the later environmental review of parking structures. “[T]he later the environmental review process begins, the more bureaucratic and financial momentum there is behind a proposed project, thus providing a strong incentive to ignore environmental concerns that could be dealt with more easily at an early stage of the project.” (.Laurel Heights, supra, 47 Cal.3d at p. 395.) Here, proponents of parking structures will be able to say, “Well, we’ve got the convention center, so what do we do with all the cars if we don’t build the structures?” In my view, this is not what CEQA has in mind when it requires environmental review of all reasonably foreseeable consequences of a project. (Id. at p. 396.)
On the record before us, the judgment should be reversed.
A petition for a rehearing was denied May 28, 1991, and appellants’ petition for review by the Supreme Court was denied August 22, 1991.
Section 15064, subdivision (d) provides: “In evaluating the significance of the environmental effect of a project, the lead agency shall consider both primary or direct and secondary or indirect consequences. [][] (1) Primary consequences are immediately related to the project such as the dust, noise, and traffic of heavy equipment that would result from construction of a sewage treatment plant and possible odors from operation of the plant. []J] (2) Secondary consequences are related more to effects of the primary consequences than to the project itself and may be several steps removed from the project in a chain of cause and effect. For example, the construction of a new sewage treatment plant may facilitate population growth in the service area due to the increase in sewage treatment capacity and may lead to an increase in air pollution.”
Section 15126, subdivision (c), entitled “Environmental Impact,” provides: “Mitigation Measures Proposed to Minimize the Significant Effects. Describe measures which could mini*1041mize significant adverse impacts, including where relevant, inefficient and unnecessary consumption of energy. The discussion of mitigation measures shall distinguish between the measures which are proposed by project proponents to be included in the project and other measures that are not included but could reasonably be expected to reduce adverse impacts if required as conditions of approving the project. This discussion shall identify mitigation measures for each significant environmental effect identified in the EIR. Where several measures are available to mitigate an impact, each should be discussed and the basis for selecting a particular measure should be identified if one has been selected. Energy conservation measures, as well as other appropriate mitigation measures, shall be discussed when relevant. Examples of energy conservation measures are provided in Appendix F. If a mitigation measure would cause one or more significant effects in addition to those that would be caused by the project as proposed, the effects of the mitigation measure shall be discussed but in less detail than the significant effects of the project as proposed. (Stevens v. City of Glendale, 125 Cal.App.3d 986.)” (Italics added.)
The promotion of regional/national conventions itself creates significant consequences, because the EIR states this measure “would probably” require more hotel accommodations in order to make it viable.
The EIR says the downtown Sacramento parking study notes a proposal to expand lot E (12th and I St.) to provide 381 spaces; expand the east end garage (I St. between 10th and 11th) to provide 1,058 spaces; and develop lot C (14th and H St.) to provide 733 spaces. In addition, the Hyatt Hotel is intended to provide some public parking. “This additional parking was not included in the demand analysis.”
At oral argument, the City asserted consideration of this document was sanctioned by the decision of our Supreme Court in Citizens of Goleta Valley v. Board of Supervisors (1990) 52 Cal.3d 553 [276 Cal.Rptr. 410, 801 P.2d 1161]. I find nothing in the case supporting the City’s view.
In any event, the document does not help the City’s case. As with the EIR, the numbers reflecting parking availability are unsupported by substantial evidence and indeed contradict the numbers in the EIR. Thus, the document refers to the downtown Sacramento parking study cited in the EIR but gives different numbers. Whereas the EIR says the three parking proposals listed in the study will provide a total of 2,172 spaces, the document says the same three proposals will create 1,669 spaces. Another contradiction is that the EIR says satellite lots will provide 350 spaces, but the document places the number at 1,300. The document fails to explain how it arrives at its figure. The document further states that elimination of *1043monthly permits in lots C and E will free up 647 spaces. I fail to see how the elimination of permits will create any new spaces or reduce demand.
The only specific information that the document adds to the EIR is that 600 spaces will be built underneath the convention center expansion site.