Opinion

— On October 3, 1991, the San Francisco District Attorney, acting on behalf of the People of the State of California (appellant), filed a civil action against PKS, Inc. The complaint sought injunctive relief, restitution of moneys paid and civil penalties from PKS, based on certain alleged unfair business practices: (a) charging more for the recovery of towed vehicles than allowed by Vehicle Code1 sections 21100, subdivision (g), and 22658, subdivision (i), and San Francisco Traffic Code2 section 172.04; (b) towing parked vehicles from private property without the request or authorization of the property owner to tow each specific vehicle in violation of section 22658, subdivisions (a) and (f), and section 10851; and (c) towing parked vehicles from private property held open to the public for parking at no fee within one hour of the time the vehicles were parked in violation of section 22953, subdivision (a). The complaint was later amended to assert the same claims against Peter Koehler, president of PKS, Inc., on “alter ego” grounds.

*403Following a court trial, judgment was entered against appellant and in favor of PKS, Inc., and Peter Koehler (respondents). Appellant seeks reversal of that judgment. We affirm.

I. Procedural History

A. Summary of Appellant’s Case

As developed through extensive pretrial briefing, argument, and evidence introduced at trial, appellant attempted to demonstrate that respondents engaged in three practices which were allegedly barred under the state and local statutes set forth in the introduction to this opinion. Appellant’s first claim was that respondents violated Traffic Code section 172.043 by charging $100 per tow for vehicles towed from private property. Per appellant, it was illegal for respondents to charge more than $80 per (private) tow because the agreement between the San Francisco Police Department and the towing company with which the police had contracted set a fee of $80.4

Appellant next charged that respondents had violated the provisions of section 22658, subdivision (a), by engaging in “patrol towing.” Per appellant, respondents traveled a prescribed circuit of lots owned by private businesses with which respondents had contractual arrangements and towed cars from those lots without securing prior approval from the lot owners for each individual tow. Third, appellant charged that respondents engaged in a practice of “quick towing” — removing vehicles from lots which provide free parking to the public less than one hour after the vehicles had been parked.

B. Decision of the Trial Court

Pursuant to appellant’s request, the trial court issued a statement of decision. On the claim that respondents charged excessive fees for towing under Traffic Code section 172.04, the court found that the Legislature had preempted the field where the issue of excessive charges by towing companies is concerned. The court determined that the enactment of section 22658, *404subdivisions (i) and (j)5 precluded San Francisco’s enactment of a statute which attempted to set a standard fee or a maximum fee, employing a formula different from the one established by the Legislature. Moreover, the court noted that the provisions of section 21100, subdivision (g), which permit local authorities to license and regulate tow truck services and drivers, enable those authorities to regulate only those entities whose principal place of business or employment is within their jurisdiction. The court found that respondents’ principal place of business and employment was in San Mateo County (South San Francisco). Thus, reasoned the court, San Francisco was not expressly authorized to regulate respondents under section 21100, subdivision (g).

As to “patrol towing,” the court found that appellant failed to prove that respondents violated the provisions of section 22658, subdivision (a) or (f). The court found that appellant failed to introduce any competent evidence that respondents towed vehicles without the permission of the private property owners from whose lots the vehicles were towed. Moreover, the court determined that the 1991 enactment of subdivision (Z) of section 22658 (effective Jan. 1, 1992)6 reflected a change in existing law and that prior to January 1, 1992, a towing company was not required to obtain specific authorization for each tow.

As to appellant’s “quick tow” claim, the court determined that appellant failed to prove that respondents towed vehicles in violation of section 22953, subdivision (a). The court also determined that section 22658, subdivision (f) provided immunity for tows (including “quick tows”) requested by a property owner.7

*405H. Arguments and Standards for Review

A. Contentions on Appeal

Appellant first argues that the trial court erred in determining that section 22658, subdivision (i), has the effect of invalidating Traffic Code section 172.04. Appellant goes on to argue that section 21100, subdivision (g),8 constitutes legislative authorization for enactment of local legislation dealing with towing charges from private lots and that the trial court erred in determining that respondents’ principal place of business and employment was in San Mateo County, thus precluding San Francisco’s regulation of respondents’ business.

Appellant next contends that the trial court erred in determining that respondents’ “patrol towing” did not violate the provisions of section 22658 because (per appellant) the statute clearly requires that each tow be authorized/initiated by an individual lot owner. Finally, appellant contends with reference to the “quick tow” issue that the trial court erred in determining that towing companies, as agents of lot owners, are beyond the reach of section 22953, subdivision (a) — at least where injunctive relief is concerned.

B. Standards for Review

Appellant asserts that the issues raised on appeal involve questions of law (only) and that, consequently, this court should examine the trial court’s determination “de nova.” In our view, appellant mischaracterizes certain of the trial court’s determinations. Where the trial court relied on matters of law, we review its determinations de nova. (Goddard v. South Bay Union High School Dist. (1978) 79 Cal.App.3d 98, 105 [144 Cal.Rptr. 701].) However, where its determinations were factual, we apply a “substantial evidence” test. (Crawford v. Southern Pacific Co. (1935) 3 Cal.2d 427, 429 [45 P.2d 183].)

*406HI. Analysis

A. The Question of What Constitutes an “Excessive” Charge for Private Tows Has Been Determined by the Legislature

“The people of California have made a limited delegation of the police power to cities. It is found in the state’s Constitution, article XI, section 7, which declares: ‘A . . . city may make and enforce within its limits all local, police, sanitary, and other ordinances and regulations not in conflict with general laws.’ ” (City of Lafayette v. County of Contra Costa (1979) 91 Cal.App.3d 749, 754 [154 Cal.Rptr. 374], italics in original.)

“Under this high authority a city’s police power ‘is subject to displacement by general state law. . . .’ [Citation.] And: ‘Whenever the Legislature has seen fit to adopt a general scheme for the regulation of a particular subject, the entire control over whatever phases of the subject are covered by state legislation ceases as far as local legislation is concerned.’ [Citation.]” (City of Lafayette v. County of Contra Costa, supra, 91 Cal.App.3d atp. 754.)

“Upon recodification of the Vehicle Code in 1959, the Legislature preempted the entire field covered by that code by substituting in place of section 458 the new section 21 which now states: ‘Except as otherwise expressly provided, the provisions of this code are applicable and uniform throughout the State and in all counties and municipalities therein, and no local authority shall enact or enforce any ordinance on the matters covered by this code unless expressly authorized herein.' ” (City of Lafayette v. County of Contra Costa, supra, 91 Cal.App.3d at p. 755, italics in original.)

Section 21100, subdivision (g), permits a local entity to “license” and “regulate” tow truck services and drivers under certain limited circumstances — specifically, when their principal place of business or employment is within the jurisdiction of the local entity. The question then becomes whether or not the right to determine what constitutes an excessive charge for private tows has been “expressly” conveyed to local entities under section 21100, subdivision (g). The simple answer is “no.”

The purpose for which section 22658, subdivision (i), was enacted was to address the problem of “excessive” charges for tows from private property.9 Appellant argues that Traffic Code section 172.04 provides “a clear designation as to the ‘law enforcement agency’ referenced in subdivision [(i)] . . . .” Appellant goes on to argue that Traffic Code section 172.04 “thus *407clarifies that the city agreement on behalf of the San Francisco Police Department is to be the determinant of what is an ‘excessive charge.’ ”

Appellant’s argument misses the mark. Traffic Code section 172.04 does not clarify section 22658, subdivision (i); it establishes a different, conflicting standard from the one set by the Legislature. The Legislature established what constitutes an “excessive” charge in enacting subdivision (i). The Legislature set a clear standard — a charge for towing from private property is excessive if it is greater than that charged for towing made at the request of “a law enforcement agency under an agreement between the law enforcement agency and a towing company” in the city or county in which the private property is located. (Italics added.)

Contrary to appellant’s argument, the Legislature did not provide that a local authority could or should set a separate standard, based on one specific contract between one specific towing company designated by that local authority and one specific law enforcement agency within the jurisdiction of that authority. Our view of the Legislature’s intent is reinforced by other provisions of section 22658. For example, in enacting subdivision (a) of section 22658, the Legislature established a uniform system under which private property owners may cause the removal of vehicles from their property. Subdivision (1) of subdivision (a) requires that a private property owner display a sign with the telephone number of “the local traffic law enforcement agency. . . .” (Italics added.) If the Legislature had intended that the standard of subdivision (i) be that of a specific agreement between a specific towing company and the local traffic law enforcement agency, as set forth in subdivision (a), it would have done so. A fair reading of section 22658, subdivision (i), and section 21100, subdivision (g), taken together, is that local authorities may license and regulate tow truck services or drivers whose principal place of business or employment is within their jurisdiction; however, that regulation cannot include setting a separate standard for the determination of “excessive” charges for private tows from that established by the Legislature.10

In the case at hand, uncontradicted evidence was introduced that respondent had several contracts with law enforcement agencies in the City and County of San Francisco which set rates for tows requested by those *408agencies of $100 to $116.11 Thus, charges by respondents at a rate of $100 for the period covered by the complaint did not exceed the standard set by the Legislature.12

B., C *

The judgment is affirmed.

Reardon, J., concurred.

— I concur in the judgment and in the reasoning of part III(A) of the lead opinion. With respect to parts 111(B) and III(C), I concur in the judgment only.

A petition for a rehearing was denied July 22, 1994.