MEIERHENRY, Justice.

[¶ 1.] The question in this case is whether a city can enforce its speed limit ordinance, instead of state law, on a state trunk highway and thereby direct the fine to city coffers rather than local school districts. This question was brought to the South Dakota Attorney General's attention after the City of Colman, South Dakota, ticketed speeders on State Highway 34 with a city ordinance violation rather than a state law violation. The Attorney General notified Colman that the city did not have authority to enforce the city's speed limit ordinance on the state highway. Colman rejected the Attorney General's opinion and filed an action for declaratory judgment in circuit court. The circuit court agreed with the Attorney General. Colman appeals. We affirm and hold that Colman does not have authority to enforce its city ordinance rather than state law.

[¶ 2.] Highway 34 is part of the state trunk highway system and passes through Colman's city limits. The speed limit on Highway 34 is set by state law and violations are classified as misdemeanors. See SDCL 32-25-7. Colman's city council enacted city ordinance 10.0201, which duplicated the state speed limit and penalty classification. See SDCL 32-25-7. When enforcing the speed limit, Colman's law enforcement officers ticketed speeders with a city ordinance violation rather than a state law violation.1

[¶ 3.] The main difference between enforcing the city ordinance rather than state law lies in the distribution of the fine proceeds. South Dakota law directs that 65 percent of fines collected from city violations go to the city treasury and 35 percent to the State. SDCL 16-2-34. In contrast, 100 percent of the fines collected from state law violations go to school districts in the county where the fine is assessed. S.D. Const. art. VIII, § 3.2

[¶ 4.] Colman claims it has statutory authority to enforce its own ordinance rather than state law. Colman gleans its authority from the following four statutes: SDCL 9-31-1; SDCL 9-31-3; SDCL 9-29-1; and, SDCL 32-14-5. The first statute, SDCL 9-31-1, gives a city the power to regulate the use of certain vehicles. It provides that "[e]xcept as otherwise provided, every [city] may regulate the use of motor vehicles, bicycles, house cars, house trailers, trailer coaches, traction engines, tractors, and road rollers." Id. The second statute, SDCL 9-31-3, grants a city the power to regulate the speed of vehicles. It provides that "[e]very [city] shall have power to regulate the speed of animals, vehicles, motor vehicles, cars, and locomotives." Id. The third statute, SDCL 9-29-1, gives a city the power to enforce its ordinances within, and one mile surrounding, the city limits.3 Id. Finally, SDCL 32-14-5 provides cities with limited regulatory authority for "traffic on highways under their jurisdiction." Id.4 Colman claims these statutes, collectively, demonstrate that the Legislature "intended to empower [cities] with the authority to regulate traffic over all territory within their corporate limits."

[¶ 5.] In analyzing Colman's claim, we continue to apply our longstanding rule that cities have only those powers expressly granted to them by the Legislature. Elkjer v. City of Rapid City, 2005 SD 45, ¶ 9, 695 N.W.2d 235, 239. "A grant of authority includes those incidental or implied powers that are necessary to enable a municipality to perform the function authorized." Id. (citations omitted). Because cities have "no inherent powers, and none of the attributes of sovereignty," the scope of their implied powers falls under "a reasonably strict standard." Id. "Whatever latitude these implied powers might include will depend upon the circumstances of each case." Id.

[¶ 6.] We acknowledge that the four statutes Colman relies on give a city the power to regulate certain traffic within its jurisdiction. But we must view the city's limited jurisdiction in the context of the broader jurisdictional scheme of the state highway system. The Legislature categorizes state highways as: (1) municipal streets and alleys; (2) state trunk highways; (3) county highways; and, (4) secondary highways. See SDCL 31-1-4.

[¶ 7.] The Legislature also "clarif[ies] the duties and powers of the various governmental state agencies charged with the administration of the highways in South Dakota." SDCL 31-1-5.5 The Legislature charges the Department of Transportation with the "control[ ] and supervis[ion]" of "highways designated by statute" as the "state trunk system." SDCL 31-1-5(1). County commissioners oversee county and secondary highways, and township supervisors administer township highways. Id.

[¶ 8.] Additionally, the Legislature specifically gives the State Transportation Commission, a commission in the South Dakota Department of Transportation, the authority to regulate speed limits on the state trunk highway system. SDCL 1-44-4; SDCL 32-25-7. State law outlines how speed limits on state trunk highways are set and what penalties exist for violations:

SDCL 32-25-7.

[¶ 9.] The Legislature's overall scheme and apportionment of authority over the various highways signals legislative intent to preempt the field. This scheme confines a city's authority to the "streets and alleys within the limits of municipal corporations." SDCL 31-1-4. Other highways are under the supervision and control of other governmental agencies. See SDCL 31-1-5. Notably, the Legislature gives the control and supervision of a state trunk highway, such as Highway 34, to the State Department of Transportation and the specific power to set speed limits to the State Transportation Commission. SDCL 31-1-5(1). This delegation of control and supervision of state trunk highways to state agencies demonstrates the Legislature's intent in this field.

[¶ 10.] We have said that one way to determine if a state law preempts a local ordinance is to look at whether the state law "occup[ies] a particular field to the exclusion of all local regulation." In re Yankton County Com'n, 2003 SD 109, ¶ 15, 670 N.W.2d 34, 39. We find preemption if "the scheme of [state] regulation is sufficiently comprehensive to make [a] reasonable [] inference that [the Legislature] `left no room' for supplementary [city] regulation." Id. ¶ 16, 670 N.W.2d at 39.

[¶ 11.] Here, the regulatory scheme gives control of state trunk highways to a state agency. The speed limits are set by a state agency and violations are state offenses. Moreover, the Legislature has not expressly authorized cities to regulate speed limits on state trunk highways. See SDCL 32-14-3. A reasonable inference drawn from the statutes is that the Legislature intended to "occupy the field" of regulating state trunk highways and did not intend to leave "room for supplementary [city] regulation[.]" See Yankton County Com'n, 2003 SD 109, ¶ 21, 670 N.W.2d at 41. Consequently, we hold that Colman did not have authority to enforce a city speed limit ordinance on state Highway 34.

[¶ 12.] Affirmed.

[¶ 13.] GILBERTSON, Chief Justice, and KONENKAMP, ZINTER, and SEVERSON, Justices, concur.