*1008Real party in interest Laurel Way Joint Venture (LWJV) appeals from the trial court's order setting aside a planned development permit (PDP) issued by the City of Redwood City (City). LWJV represents 14 sets of owners of 18 undeveloped lots in the City who seek to build up to 16 homes on a street known as Laurel Way. Following the preparation of an environmental impact report (EIR), the City issued the PDP for a planned upgrade to Laurel Way, covering the first phase of a development project referred to as the Laurel Way Development Project (Project). The PDP includes such elements as a cul-de-sac for a fire truck turnaround, a fire hydrant, new streetlights, pedestrian pathways, an open space land dedication, and other civic improvements. It does not include any development on the individual lots. The court set aside the PDP, concluding the City had abused its discretion by failing to evaluate the legal status of the 18 lots under the Subdivision Map Act ( Gov. Code, § 66410 et seq. )1 (SMA or the Act).

*556Because issues regarding the legal status of the individual lots under the SMA are not ripe for judicial review, we now reverse.

FACTUAL BACKGROUND AND PROCEDURAL HISTORY

The Project site along Laurel Way consists of approximately 4.75 acres. The site is contained in a hillside canyon and is steeply sloped. Laurel Way is currently a private, dead end street that is only partially paved. The Project includes undeveloped properties located along the unpaved end of the street.2 The subject lots on the site range in size from between approximately 7,200 to 24,525 square feet, which is similar to the lot sizes found elsewhere in the general neighborhood. The average slopes on the subject lots range from 19 percent to 41 percent.

The City has divided the Project into two phases. The first phase involves improvements to the Project area, including paving the roadway, installing utilities and sewer connections as well as retaining walls, landscaping, drainage infrastructure, and planting replacement trees. The second phase involves the construction of individual residences on the lots. The second phase is not to commence until the first phase has been completed and approved by the City's community development director. The PDP at issue in this case pertains to the first phase of the Project.

*1009On May 1, 2006, LWJV filed its first application with the City for a PDP. Seven months later, the City commenced review for an EIR.3 Between October 2007 and June 2009, the City planning staff held several workshops and public meetings concerning the Project.

In February 2010, the City circulated a draft EIR for public review, detailing the Project's potential environmental impacts and proposed mitigation measures.

On August 24, 2010, the City's planning commission certified a final EIR, adopting findings for mitigation measures, including a mitigation monitoring program. The EIR concluded that the Project as then proposed would have no significant environmental impact after mitigation.

On September 9, 2011, LWJV withdrew its original PDP application and submitted a new application, reducing by two the proposed number of residences.

In March 2013, a revised final EIR was prepared. The EIR was approved by the City's planning commission.

On April 1, 2013, the City's planning commission adopted a resolution approving the PDP. The resolution includes 63 conditions of approval.

On January 13, 2014, the City Council passed a resolution (Resolution) upholding the City planning commission's decision to certify the EIR and modifying the commission's approval of the PDP. The Project as approved contemplates that up to 16 new houses will be built, subject to additional permits, as well as to extensive additional conditions, and requirements.4

On February 13, 2014, respondent Save Laurel Way (SLW) filed a petition for writ *557of mandate and a complaint for injunctive relief asserting four causes of action for (1) violation of the City's municipal code and zoning ordinance, *1010(2) violation of the state Planning and Zoning Law (§ 65300 et seq.), (3) violation of the SMA, and (4) violation of CEQA ( Pub. Resources Code, § 21000 et seq. ).

On August 8, 2014, the City filed its answer to the petition and complaint.5 In its answer, it indicated its view that the "lots within the Project area are legal conforming lots created by a tentative map in 1926, which lots do not conform with the current requirements of the [Redwood City] Zoning Code [RZO], but which the Zoning Code allows to nonetheless be developed." That same day, LWJV also filed its answer to the petition and complaint.

On October 24, 2014, a court trial was held, consisting of oral argument based on the administrative record and trial briefs filed by the parties.

On January 23, 2015, the trial court issued a proposed statement of decision.

On February 8 and 9, 2015, petitioners and real parties filed objections to the proposed statement of decision.

On November 20, 2015, the trial court issued the final statement of decision setting aside the PDP and vacating the City's certification of the EIR. Invoking the SMA and recent cases addressing older subdivision maps, the court concluded the City had abused its discretion in approving the Project because "[t]he facts and law do not support a finding that there are 16 legal lots upon which 16 homes can be built, and do not support a finding that the property owners have a vested right to develop each of the 16 alleged lots." LWJV has appealed.

DISCUSSION

Among the arguments advanced on appeal, LWJV contends that the SMA does not require a city to evaluate lot legality before granting development permits or preparing an EIR under CEQA. The contention is persuasive. Because the SMA's provisions were not invoked by the City's action in approving the PDP and the EIR, we conclude the subdivision map issues addressed by the trial court are not ripe for judicial review.

I. Standard of Review

" Code of Civil Procedure section 1094.5, the state's administrative mandamus provision ... structures the procedure for judicial review of adjudicatory *1011decisions rendered by administrative agencies. ... Subdivision (b) of section 1094.5 prescribes that when petitioned for a writ of mandamus, a court's inquiry should extend, among other issues, to whether 'there was any prejudicial abuse of discretion.' " ( Topanga Assn. for a Scenic Community v. County of Los Angeles (1974) 11 Cal.3d 506, 514-515, 113 Cal.Rptr. 836, 522 P.2d 12.) "Abuse of discretion" is defined to include instances in which the administrative agency "has not proceeded in the manner required by law, the order or decision is not supported by the findings, or the findings are not supported by the evidence." ( Code Civ. Proc, § 1094.5, subd. (b).) Additionally, the state Planning and Zoning Law provides: "No action ... by any public agency ... on any matter subject to this title shall be held invalid or set aside by any court ... by reason of any error, irregularity, informality, neglect, or omission (hereafter, error) as to any matter pertaining to ... findings ... subject to this title, unless the court finds that the error was prejudicial and that the party complaining or appealing suffered substantial injury from that error and that a different result would have been probable if the error had not occurred. There shall be no presumption that error is prejudicial or that injury was done if the error is shown." (§ 65010, subd. (b).) *558It is presumed that an administrative agency regularly performed its duty, and the burden is on the party challenging the agency's actions to prove an abuse of discretion. ( Young v. Gannon (2002) 97 Cal.App.4th 209, 225, 118 Cal.Rptr.2d 187 ; see Kutzke v. City of San Diego (2017) 11 Cal.App.5th 1034, 1042, 218 Cal.Rptr.3d 206 ["[i]t is ' "not the role of the courts to micro-manage these development decisions. Our function is simply to decide whether the city officials considered the applicable policies and the extent to which the proposed project conforms with those policies, whether the city officials made appropriate findings on this issue, and whether those findings are supported by substantial evidence." ' " ].)

Our role on appeal is identical to that of the trial court. Thus, we are not bound by the trial court's determinations. ( Lucas Valley Homeowners Assn. v. County of Marin (1991) 233 Cal.App.3d 130, 142, 284 Cal.Rptr. 427 ; Alberstone v. California Coastal Com . (2008) 169 Cal.App.4th 859, 863, 86 Cal.Rptr.3d 883.) The only exception to this standard of review arises where the trial court has made findings as to foundational matters of fact that could be conclusive on appeal; such findings must be accorded deference where supported by substantial evidence. ( Mike Moore's 24-Hour Towing v. City of San Diego (1996) 45 Cal.App.4th 1294, 1303, 53 Cal.Rptr.2d 355.)

*1012II. The SMA

1. General Principles

The SMA is " 'the primary regulatory control' " which governs the subdivision of real property. ( Gardner v. County of Sonoma (2003) 29 Cal.4th 990, 996, 129 Cal.Rptr.2d 869, 62 P.3d 103 ( Gardner ); Hill v. City of Clovis (2000) 80 Cal.App.4th 438, 445, 94 Cal.Rptr.2d 901 ( Hill ).) Under the SMA, the " '[r]egulation and control of the design and improvement of subdivisions' "6 is vested in local agency legislative bodies such as a city council, which must adopt ordinances on the subject. (See § 66411; Gardner, at pp. 996-997, 129 Cal.Rptr.2d 869, 62 P.3d 103.) Generally, developers must design their subdivisions in conformity with applicable general and specific plans and comply with local ordinances. ( Id . at p. 997, 129 Cal.Rptr.2d 869, 62 P.3d 103 ; see Hill, at p. 445, 94 Cal.Rptr.2d 901.)

Under the current version of the SMA, subdivisions ordinarily " 'may be lawfully accomplished only by obtaining local approval and recordation of a tentative and final map pursuant to section 66426, when five or more parcels are involved, or a parcel map pursuant to section 66428 when four or fewer parcels are involved. [Citation.] A local agency will approve a tentative and final map or a parcel map only after extensive review of the proposed subdivision and consideration of such matters as the property's suitability for development, the adequacy of roads, sewer, drainage, and other services, the preservation of agricultural lands and sensitive natural resources, and dedication issues. [Citations.]' [Citation.] The [SMA] prohibits the sale, lease, financing or improvement of any parcel or parcels of real property for which a final map or parcel map is required under the Act unless a final map or parcel map has been recorded." ( Abernathy Valley, Inc. v. County of Solano (2009) 173 Cal.App.4th 42, 48, 92 Cal.Rptr.3d 459 ( Abernathy ).)

The subject lots at issue in the present case were created as part of a residential *559subdivision when the Project area was under the unincorporated San Mateo County jurisdiction. The applicable 1926 subdivision map (1926 Map) reflected a survey, platting into lots, and creation of hundreds of numbered parcels, for purposes of division of land for sale. The City annexed the property along the end of Laurel Way, including the lots that are the *1013subject of the PDP, in 1969. The Project area is currently designated Low Density Residential under the General Plan, and Residential-Hillside under the Zoning Ordinance.

2. Historical Overview of the SMA

As noted above, the lots within the Project site were subdivided in 1926. To understand the basis of the trial court's ruling it is necessary to review the history of the SMA.

"The Subdivision Map Act has regulated the division of land in California since the nineteenth century. 'The first Subdivision Map Act was enacted in 1893. Subsequent versions of the Act were enacted in 1907, 1929, 1937 and 1943. The modern latest version of the Act was enacted as part of the Government Code in 1974.' [Citation.] 'All versions of the Act enacted subsequent to the first Act in 1893 contained grandfather clauses exempting from the current Act those subdivisions established in compliance with laws in effect when recorded.' [Citation.]

"In the earliest twentieth-century version of the Act, 'development was left almost entirely to the discretion of the developer. The act provided for no governmental regulation, and required submission of a subdivision map to local officials only to allow them to check its accuracy in order to assure good title to the resulting parcels.' [Citation.] 'With the advent of zoning in the 1920s, subdivision mapping began to assume some importance as a land use control.' [Citation.] The 1929 version of the Act first authorized local subdivision regulations. [Citation.] The 1937 enactment first prohibited sellers from conveying subdivided lots without prior local approval. [Citation.] 'The 1937 enactment was the basis for the 1943 codification which, together with many amendments thereto, remained in effect until the 1974 recodification. [Citation.]' [Citation.] But by the late 1960's, 'many uncoordinated amendments' had rendered the Act 'so complex and disorganized that the need for recodification was apparent. Following attempts in 1971, 1972 and 1973, the Subdivision Map Act, which had been codified in the Business and Professions Code ( [§] 11500 et seq. ), was recodified in [ Government Code section] 66410 et seq. ' " ( V an't Rood v. County of Santa Clara (2003) 113 Cal.App.4th 549, 563, 6 Cal.Rptr.3d 746.)

3. The SMA's Grandfather Provision

The trial court focused on whether the 1926 Map is covered by the SMA's current grandfather provision, which provides that the prohibitions on selling, leasing, financing, or improving parcels on maps that do not comply with the SMA do not apply to "any parcel or parcels of a subdivision offered *1014for sale or lease, contracted for sale or lease, or sold or leased in compliance with or exempt from any law (including a local ordinance), regulating the design and improvement of subdivisions in effect at the time the subdivision was established ." (§ 66499.30, subd. (d), italics added; see Gardner, supra, 29 Cal.4th at p. 998, 129 Cal.Rptr.2d 869, 62 P.3d 103.) The trial court concluded it was "highly unlikely" that the 1926 Map was " 'in compliance with or exempt' " from any law " 'regulating the design and improvement' " of subdivisions as specified in this provision because the County of San Mateo did not have any such laws in 1926.7 *560Gardner , the leading case interpreting section 66499.30, subdivision (d), stands for the proposition that maps recorded before the effective date of the first statewide map legislation (which was enacted in 1893), and that were not subject to other local statutes or regulations governing the subdivision of property at the time they were recorded, are not entitled to the protection of the grandfather provision. ( Gardner, supra, 29 Cal.4th at pp. 1001, 1002-1003, 129 Cal.Rptr.2d 869, 62 P.3d 103.) Specifically, the Supreme Court held that the recording of a map before 1893 did not "establish" the subdivision depicted on the map within the meaning of section 66499.30. ( Gardner , at pp. 1000-1001, 129 Cal.Rptr.2d 869, 62 P.3d 103 ; see pp. 1003-1004 [recordation before 1893 also did not "create" subdivision within meaning of § 66451.10, subd. (a) ]; p. 1006.) Gardner left open the question of whether maps recorded under statewide subdivision map laws in effect between 1893 and 1929 legally created or "established" subdivision parcels when recorded and thus were covered by the grandfather provision. ( Gardner, at p. 1001, fn. 7, 129 Cal.Rptr.2d 869, 62 P.3d 103.)

Subsequently, in Witt , the Court of Appeal ruled that maps filed in compliance with subdivision map laws in effect in 1915 are not covered by section 66499.30, subdivision (d). ( Witt, supra, 165 Cal.App.4th at p. 548, 81 Cal.Rptr.3d 123.) The court concluded these early laws did not purport to regulate the "improvement" of the subdivision and thus they did not regulate the " 'design and improvement' " of subdivisions within the meaning of the grandfather clause. ( Ibid. ) Nor did such laws regulate the " 'design' " of subdivisions since they "omitted any regulation of the primary characteristic of a subdivision-the division of a large parcel into smaller usable lots." ( Id . at p. 562, 81 Cal.Rptr.3d 123.) The 25-lot map at issue in Witt , for example, was "a planning anachronism, merely a grid laid across a parcel of land. There is no indication that any consideration was given to the appropriate siting of residences, lot drainage, the feasibility and construction of utility service, or any of the many other issues that arise when development occurs. It is difficult to imagine a plan for real estate development more at odds with modern subdivision regulation." ( Id. at p. 563, 81 Cal.Rptr.3d 123.)

*1015In Abernathy , a property owner sought a writ of mandate to compel the county to issue a "certificate of compliance"8 reflecting that one of 25 lots identified on a parcel map recorded in 1909 was in compliance with the requirements of the SMA and thus could be legally sold as a separate parcel. ( Abernathy, supra, 173 Cal.App.4th at p. 45, 92 Cal.Rptr.3d 459.) In reversing the trial court's grant of relief, the appellate court explained that "even assuming [the lot] was 'established' when the [parcel map] was recorded in 1909," the subdivision law in effect at that time was insufficiently detailed to qualify as one which " 'regulat[ed] the design and improvement of subdivisions.' " ( Id. at p. 51, 92 Cal.Rptr.3d 459.) Consequently, the court could not certify those lots as in compliance with the Act: "To permit maps recorded in compliance with these laws to *561be grandfathered under the current Act would seriously undermine the objectives of the Act." ( Abernathy, at p. 51, 92 Cal.Rptr.3d 459.)

In Hays v. Vanek (1989) 217 Cal.App.3d 271, 266 Cal.Rptr. 856 ( Hays ), the defendant asserted a subdivision map filed in 1926 had validly subdivided his 40 acres into approximately 630 parcels, all of which he was entitled to sell separately. ( Hays , at p. 287, 266 Cal.Rptr. 856.) The appellate court found that a subdivision map filed in 1926, the same year as the map at issue here, would be subject to the requirements of the 1907 version of the SMA. ( Hays , at p. 288, 266 Cal.Rptr. 856.) Significantly, the Abernathy court's holding that the lot at issue did not qualify for grandfathering was also based on the laws reflected in the 1907 SMA. ( Abernathy, supra, 173 Cal.App.4th at p. 51, 92 Cal.Rptr.3d 459.)

4. The Trial Court's Ruling

The trial court reasoned that "the issue is not whether the 1926 subdivision map here complied with the law as of 1926, but whether it complies with the law now or otherwise fits squarely within the grandfather clause under the present language." Relying on Abernathy and Hays, the court concluded there was no showing in the record that any applicable "design and improvement" laws existed when the 1926 Map was filed. Thus, it did not appear that the parcels in the Project would fall within the SMA's grandfather provision. However, the trial court did not make an ultimate finding as to whether the lots are illegal. Rather, it found that the city abused its discretion because it expressly found all 16 Project lots were legally created without having considered their status under the SMA. While the court's reasoning is not inconsistent with the pertinent authorities, its ultimate conclusion is flawed.

*1016III. Issues Under the SMA Are Not Ripe for Review9

The City concluded the subject lots are presumptively entitled to legal status based on section 33.2 of the RZO. That section provides, in part: "A nonconforming lot or parcel may be used for development subject to compliance with all other provisions of this article and other applicable codes. ..." It is true the City did not also separately evaluate the status of the lots under the SMA.10 However, it does not necessarily follow that the City committed a prejudicial abuse of discretion in issuing the PDP and certifying the EIR.

*562Unlike the present case, in the principal cases cited to by the trial court and relied on by the respondents here, the issues concerned landowners seeking status or relief under the current version of the SMA for properties subdivided under older maps. In Abernathy , a landowner had appealed after a county denied his request to record a certificate of compliance with the SMA for a lot that had been subdivided under a map recorded under the 1907 SMA. ( Abernathy , supra , 173 Cal.App.4th at p. 45, 92 Cal.Rptr.3d 459.) In Hays, a defendant sought declaratory relief that he need not comply with current SMA based on the argument that his property had been validly subdivided under a 1926 subdivision map. ( Hays , supra , 217 Cal.App.3d at p. 287, 266 Cal.Rptr. 856.) In Gardner , the plaintiff landowners sought to establish that property subdivided under an 1865 subdivision map was entitled to legal recognition under the SMA. ( Gardner , supra , 29 Cal.4th at p. 994, 129 Cal.Rptr.2d 869, 62 P.3d 103.)11

It is undisputed that the PDP grants authorization to proceed only with infrastructure improvements to the Project area.12 As LWJV correctly notes, nothing in the SMA prohibits construction of improvements such as those *1017allowed by the PDP. The prohibitions of the SMA are found at section 66499.30, subdivisions (a) and (b): "No person shall sell, lease, or finance any parcel or parcels of real property or commence construction of any building for sale, lease or financing thereon" without compliance with, or exemption from, the SMA. (Italics added.) Here, the PDP does not allow any owner to construct any buildings on any of the subject parcels. Whether any building will be constructed will turn on the issuance of permits during the second phase of the Project.

"The ripeness requirement, a branch of the doctrine of justiciability, prevents courts from issuing purely advisory opinions. [Citation.] It is rooted in the fundamental concept that the proper role of the judiciary does not extend to the resolution of abstract differences of legal opinion. It is in part designed to regulate the workload of courts by preventing judicial consideration of lawsuits that seek only to obtain general guidance, rather than to resolve specific legal disputes. However, the ripeness doctrine is primarily bottomed on the recognition that judicial decision making is best conducted in the context of an actual set of facts so that the issues will be framed with sufficient definiteness to enable the court to make a decree finally disposing of the controversy." ( Pacific Legal Foundation v. California Coastal Com . (1982) 33 Cal.3d 158, 170, 188 Cal.Rptr. 104, 655 P.2d 306) (Pacific Legal ).To be ripe, " '[t]he controversy must be definite and concrete, touching the legal relations of parties having adverse legal interests. [Citation.] It must be a real and substantial controversy admitting of specific relief through a decree of a conclusive character, as distinguished from an opinion advising what the law would be upon a hypothetical state of facts.' " ( Id. at pp. 170-171, 188 Cal.Rptr. 104, 655 P.2d 306, quoting Aetna Life Ins. Co. v. Haworth (1937) 300 U.S. 227, 240-241, 57 S.Ct. 461, 81 L.Ed. 617.)

There are no issues ripe for adjudication under the SMA in the present case because that legislation is not squarely implicated by the City's actions in approving *563the PDP and certifying the EIR.13 Again, the SMA does not prohibit development permit approvals. Nor does it apply to the certification of environmental studies under CEQA.14 Simply put, the City did not make any decisions invoking the SMA, much less one subject to a writ of mandate for being in violation of that legislation. Unlike Abernathy, Hays, and Gardner , no party here has sought a certificate of compliance or other relief under the SMA. And while LWJV takes the position that the City's *1018grant of the "master" PDP necessarily compels the issuance of certificates of compliance for all lots in the Project area (see § 66499.35, subd. (c)), at trial the City's counsel stated that the City had not yet considered this issue because the first phase of the Project does not involve direct dealings with the individual lot owners. While it appears the SMA's provisions may come into play as the individual members of LWJV move to construct homes on their properties, at this juncture any judicial pronouncements as to these issues is premature.15

Our holding in this appeal is a limited one. We conclude the approval of the PDP in Phase 1 of the Project involves only the development of an infrastructure for the land involved. The SMA is not implicated in Phase 1. The validity of conveyance by implication in Phase 1 is not before us. Adjudication of any issue under the SMA is not ripe. In light of our conclusion, we need not address the parties' remaining arguments.

DISPOSITION

The judgment is reversed.

We concur:

Humes, P. J.

Margulies, J.