108OAG81

Gen. 81] 81

TRANSPORTATION

LOCAL GOVERNMENT – PREEMPTION – TRAFFIC STOPS –
WHETHER A LOCAL ORDINANCE PROHIBITING LOCAL
POLICE OFFICERS FROM STOPPING DRIVERS SOLELY FOR
CERTAIN TRAFFIC OFFENSES WOULD BE PREEMPTED BY
THE MARYLAND VEHICLE LAW

September 15, 2023
The Honorable Evan Glass
President, Montgomery County Council

The Maryland Vehicle Law—the State statute regulating the
use of motor vehicles—defines numerous offenses for which police
officers may issue traffic citations. Motor vehicle offenses can be
categorized as either “primary” or “secondary.” If a police officer
observes a primary offense, they may ordinarily stop and cite the
driver for that offense, without more. But an officer cannot stop a
driver for a secondary offense standing alone. Instead, an officer
may issue a citation for a secondary offense only after stopping the
driver for a separate primary offense. A bill pending before the
Montgomery County Council—the Safety and Traffic Equity in
Policing Act, or “STEP Act”—would require Montgomery County
police officers to treat certain traffic offenses as secondary, even
though the Maryland Vehicle Law has not defined them as such.
The STEP Act would also limit Montgomery County officers’
ability to ask for consent to search a vehicle, or its occupants,
during a traffic stop.

On behalf of the Montgomery County Council, you requested
an opinion of the Attorney General on whether the Maryland
Vehicle Law would preempt the STEP Act. In accordance with our
policy on opinion requests, you provided a memo from the County
Attorney concluding that the Vehicle Law would preempt the
provisions of the STEP Act relating to secondary offenses but that
the STEP Act’s remaining provisions would be valid. You also
provided a memo from a Legislative Attorney for the Council,
concluding that the Vehicle Law would not preempt any portion of
the STEP Act.

In our view, the Vehicle Law would expressly preempt the
STEP Act’s provision designating certain traffic offenses as
secondary. Under the Vehicle Law, no local government may
make or enforce a “local law, ordinance, or regulation on any
subject covered by the Maryland Vehicle Law.” Md. Code Ann.,
82 [108 Op. Att’y

Transp. (“TR”) § 25-101.1(b)(3). As we will explain, the Maryland
Vehicle Law covers the subject of which motor vehicle offenses
are subject to primary enforcement and which are subject to
secondary enforcement. More specifically, the Vehicle Law
establishes a general rule that all motor vehicle offenses are subject
to primary enforcement. It then exempts certain specific offenses
from that rule, explicitly providing secondary enforcement for
those specific offenses. Because the Vehicle Law addresses the
subject of primary versus secondary enforcement, and because the
General Assembly has chosen to designate certain offenses as
secondary while leaving the rest as primary, a local law designating
further offenses as secondary would address a subject that the
Vehicle Law covers and would thus be preempted.

Although the Vehicle Law reserves certain powers to local
governments, none of those reserved powers would authorize the
secondary-offense provisions of the STEP Act. To be clear, we do
not question a local government’s general authority to establish
rules for its own police department. Nor do we address a local
legislative body’s ability to set enforcement priorities for its local
police department in areas not subject to express preemption. We
conclude only that, whatever legislative authority a local
government otherwise has, the General Assembly has overridden
that authority for subjects the Vehicle Law addresses, including the
subject of which motor vehicle offenses are secondary.

On the other hand, the Vehicle Law would not preempt the
STEP Act’s remaining provisions. In particular, the Vehicle Law
would not preempt the STEP Act’s limitation on consent searches.
That provision would preclude an officer from requesting consent
to search a vehicle or its occupants during a traffic stop, unless
there is at least reasonable suspicion to believe a crime has been
committed. The Maryland Vehicle Law does not address the
subject of searches during traffic stops. The consent-search
provision also would not tread on an impliedly preempted field.
Nor would it conflict with any provision of the Vehicle Law,
because, again, the Vehicle Law does not address searches. There
is thus no basis to say that the Vehicle Law would preempt the
consent-search provision.1
1
We received three sets of comments on this opinion request,
generally supporting the STEP Act on legal or policy grounds. Angela
J. Davis et al., Testimony in Support of the Safety and Traffic Equity in
Policing (STEP) Act—Bill 12-23 (July 5, 2023) (“Davis Comments”);
Robert Landau, Comments of Robert Landau on the Legality of the
Montgomery County Bill 12-23 (July 25, 2023); Letter from Chelsea J.
Gen. 81] 83

I
Background
A. Traffic Stops

Traffic stops are the most common interaction between police
officers and members of the public in the United States.
Montgomery County Office of Legislative Oversight, OLO Report
No. 2021-10, A Study on Reassigning Traffic Enforcement from the
Montgomery County Police Department to the Montgomery
County Department of Transportation 5 (2021) (“OLO Report”).
Maryland law empowers police officers to order a driver to stop by
means of a “visual or audible signal.” TR § 21-904. Because the
driver, once pulled over, is not free to leave at will, a traffic stop is
a “seizure” governed by the Fourth Amendment and Article 26 of
the Maryland Declaration of Rights.2 See, e.g., Byndloss v. State,
391 Md. 462, 465 & n.1, 480 (2006). Ordinarily, though, an officer
can conduct a traffic stop without a warrant if they have reasonable
suspicion—usually through direct observation—that the driver is
violating the motor vehicle laws. State v. Williams, 401 Md. 676,
690-91 (2007). Indeed, the Maryland Vehicle Law affirmatively
authorizes officers to issue citations for motor vehicle offenses,
which in turn implies the power to stop the driver. See TR
§ 26-201. For some specific offenses, though, the authority to
conduct a stop is limited by statute, as we discuss further below.3

Crawford, Esq., to Hon. Anthony G. Brown, Attorney General (Aug. 10,
2023). We thank the commenters for their views, and we have
considered their comments in developing the analysis below.
2
Article 26 provides: “That all warrants, without oath or affirmation,
to search suspected places, or to seize any person or property, are
grievous and oppressive; and all general warrants to search suspected
places, or to apprehend suspected persons, without naming or describing
the place, or the person in special, are illegal, and ought not to be
granted.” Md. Decl. Rights Art. 26. The scope of Article 26’s protection
against searches and seizures is generally the same as the Fourth
Amendment’s. See, e.g., King v. State, 434 Md. 472, 482-83 (2013).
3
While the default rule is that motor vehicle offenses in Maryland are
misdemeanors, see TR § 27-101, some are felonies, e.g., TR
§ 20-102(c)(3) (leaving the scene of an accident when the defendant
knew or reasonably should have known that the accident resulted in
serious bodily injury or death), and others are subject only to civil
penalties, e.g., TR § 21-1414(c) (failing to pay a toll assessed by a video
monitoring system). We do not consider the question of when an officer
can stop a driver who has committed only a civil offense.
84 [108 Op. Att’y

Constitutional limits also control what the officer can do once
the driver has been stopped. A stop generally cannot last longer
than necessary to accomplish its original purpose, which is
normally to investigate the traffic violation and issue a warning or
citation if appropriate. See, e.g., Ferris v. State, 355 Md. 356, 372
(1999). But an officer may continue to detain the vehicle if the
officer has reasonable suspicion that some other criminal activity
is afoot. Id. And an officer may also request consent to search the
vehicle or its occupants. See id.; Scott v. State, 247 Md. App. 114,
132, 150-52 (2020). A warrantless search based on consent is
ordinarily valid with or without reasonable suspicion or probable
cause, even in the context of a traffic stop. See State v. Green, 375
Md. 595, 609-10 (2003); Gamble v. State, 318 Md. 120, 123-24
(1989). But see Md. Code Ann., Crim. Proc. (“CP”) § 1-211(c)
(providing that evidence obtained through certain cannabis-related
searches is inadmissible even if obtained with consent).4

Traffic stops serve an important public safety function. They
enable officers to deter and stop dangerous driving, which in turn
helps reduce crashes and injuries. OLO Report at i, 5. But
advocates and researchers have raised concerns about racial
disparities in the frequency of traffic stops, especially in the
frequency of traffic stops where the officer’s primary motivation is
to search for evidence of other crimes. Id. at 76-77. Such
“investigatory” stops have been upheld against Fourth Amendment
challenge by the United States Supreme Court, see Whren v. United
States, 517 U.S. 806, 813 (1996), but are often criticized as
“pretextual,” see, e.g., Wayne R. LaFave, The “Routine Traffic
Stop” from Start to Finish: Too Much “Routine,” Not Enough
Fourth Amendment, 102 Mich. L. Rev. 1843, 1852-61, 1902-03
(2004); Snyder v. State, No. 1127, Sept. Term, 2021, 2023 WL
1497289, *8-*10 (Md. App. Ct. Feb. 3, 2023) (unreported)
(Friedman, J., concurring) (criticizing Whren and arguing that the
Supreme Court of Maryland should adopt a rule against
“pretextual” stops under Article 26 of the Declaration of Rights).5
4
Other exceptions to the warrant requirement, such as the “plain
view” exception or the “automobile exception,” may apply in the context
of a traffic stop. See Livingston v. State, 317 Md. 408, 412-13 (1989);
107 Opinions of the Attorney General 153, 162-63, 166 n.20 (2022).
However, because the STEP Act does not address these exceptions, we
need not discuss them here.
5
As the law professors’ comments to our Office put it, “some police
officers use traffic stops to racially profile black and brown drivers.
They use traffic stops as a pretext for stopping these drivers so they can
look inside their cars and ask for consent to search, even though they
Gen. 81] 85

Research indicates that Black and Latino drivers are stopped at
higher rates than white drivers for “minor” or “technical” offenses
(i.e., those that do not directly threaten a crash or injury). OLO
Report at 76-77 & nn.4-6 (citing social science literature). And
such “technical” violations are the most common basis for
“investigatory” stops. See id. The concern, then, is that police
freedom to conduct traffic stops for “technical” violations is a
major source of racial disparity in traffic enforcement.
In Maryland, 125 law enforcement agencies conducted more
than 482,000 traffic stops in 2021. See Governor’s Office of Crime
Prevention, Youth, and Victim Services, Race-Based Traffic Stop
Data Dashboard, https://goccp.maryland.gov/data-dashboards/traffic-
stop-data-dashboard/ (enter “2021” for “Year”) (last visited Sept.
12, 2023) (“Data Dashboard”). There are several law enforcement
agencies with the power to make traffic stops in Montgomery
County (or at least parts of the County), including the Montgomery
County Police Department (“MCPD”), the Maryland State Police,
the Montgomery County Sheriff’s Office, and municipal police
departments. See id.; OLO Report at 13 n.17. Because some of
these agencies are created by local law as arms of local
government, the question arises whether local governments can
regulate the ability of their police departments to make traffic stops.
The answer to that question depends on the preemptive scope of
the Maryland Vehicle Law.

B. The Maryland Vehicle Law

The Maryland Vehicle Law (Titles 11 through 27 of the
Transportation Article, Maryland Code) regulates motor vehicle
ownership and operation in the State. Its purpose is to ensure “that
traffic shall move smoothly, expeditiously and safely [and] that no
legitimate user of the highway . . . shall be killed, injured or
frustrated in such use by the improper behavior of others.”
Uniform Vehicle Code vii (National Comm. on Unif. Traffic Laws
& Ordinances 1968 rev.); see also Committee to Study Revision of
the Motor Vehicle Laws, Proposed Revision of the Motor Vehicle
Laws of the State of Maryland iii (1968) (explaining that most
recent substantive revision of the Vehicle Law was based on the
Uniform Vehicle Code).

The Vehicle Law expressly limits the lawmaking authority of
local governments. “Except as otherwise expressly authorized . . .

have no legal grounds to suspect them of criminal behavior.” Davis
Comments at 2.
86 [108 Op. Att’y

no local authority or political subdivision of this State may . . .
make or enforce any local law, ordinance, or regulation on any
subject covered by the Maryland Vehicle Law.” TR § 25-101.1(b)(3).
The statute then reiterates that “[t]he provisions of the Maryland
Vehicle Law prevail over all local legislation and regulation on any
subject with which the Maryland Vehicle Law deals.” TR
§ 25-101.1(c)(1). At the same time, the Vehicle Law grants certain
express powers to local governments, including the power of
“[r]egulating traffic by means of police officers or traffic control
devices,” TR § 25-102(a)(2), and of “regulating or prohibiting the
stopping, standing, or parking of vehicles,” TR § 25-102(a)(1).

The General Assembly enacted the earliest precursor of the
Vehicle Law in 1904, just a few years after the first automobiles
appeared in Maryland. 1904 Md. Laws, ch. 518; see also Carriage
Without Horses, Balt. Sun, Dec. 20, 1898, at 10 (announcing the
expected arrival in February 1899 of the first “horseless carriage”
in Baltimore). As cars proliferated, the rules governing them grew
more complex, and legislators became more interested in ensuring
statewide uniformity. In 1916, the General Assembly prohibited
local governments from establishing their own speed limits,
licensing or registration requirements, or motor vehicle taxes. 1916
Md. Laws, ch. 687. But State authorities soon decided stronger
preemption was needed. In 1927, the General Assembly expressly
preempted local lawmaking on any subject covered by the State
vehicle law.6 That preemption provision remains in effect, with

6
As originally enacted, the preemption provision read:
Except to the extent that they may be specifically
authorized by other provisions of this sub-title
[Article 56, Subtitle “Motor Vehicles”], no city,
county or other political sub-division of this State
shall have the right to make or enforce any
ordinance or regulation upon any subject for
which provision is made in this sub-title. The
provisions of this sub-title (except as herein
otherwise specifically provided), are intended to
be exclusive of all local and municipal legislation
or regulations, upon the various subjects with
which this sub-title purports to deal, and all public
local laws, ordinances and regulations,
inconsistent or identical therewith, or similar or
equivalent thereto, are hereby repealed; and the
charters of all municipal corporations of this State
are hereby modified so as to prohibit such
corporations from making or enforcing any
Gen. 81] 87

only limited changes, as today’s TR § 25-101.1. Former Attorney
General Thomas H. Robinson, who drafted the preemption statute,
explained that it was intended to “remove all doubt . . . and to make
it clear that the provisions of the general motor vehicle law were
exclusive of all public local laws and municipal ordinances and
regulations, covering the same subject matter.” 14 Opinions of the
Attorney General 210, 214 (1929).

The General Assembly apparently had second thoughts about
the preemption provision’s breadth. In 1929, it amended the
preemption language to recognize local governments’ authority to
adopt “reasonable traffic regulations” notwithstanding the State
law. 1929 Md. Laws, ch. 319. But in 1943, as part of a general
substantive revision of the Vehicle Law, the General Assembly
repealed that exception, restoring the preemption provision to its
1927 scope. 1943 Md. Laws, ch. 1007.

There have been two comprehensive revisions of the Vehicle
Law. Each has drawn on the Uniform Vehicle Code developed by
the National Committee on Uniform Traffic Laws and Ordinances.
The first revision, in 1943, aimed at “promoting greater uniformity
and thereby achieving greater safety.” Report of the Commission
on the Revision of the State Motor Vehicle Laws 8 (1942) (“1942
Report”). As mentioned, this revision (among other changes)
repealed the authority of local governments to adopt “reasonable
traffic regulations.” At the same time, the General Assembly
codified a list of express powers of local governments, drawn from
the Uniform Code. These included the power of “[r]egulating
traffic by means of peace officers or traffic control devices” and
“[r]egulating the standing or parking of vehicles.” Compare 1943
Md. Laws, ch. 1007 (enacting Art. 66 ½, § 135), with Uniform
Vehicle Code, Uniform Act Regulating Traffic on Highways § 28,
at 5 (Nat’l Conference on Street & Highway Safety 1938 rev.); see
also 1942 Report at 2.

The second revision, in 1970, made no substantive changes
either to the preemption provision or to the two express powers
mentioned above. 1970 Md. Laws, ch. 534 (enacting Art. 66 ½,
§§ 15-101, 15-102); see also Maryland Dep’t of Motor Vehicles,
Motor Vehicle Laws Revision 495-98 (1969) (comparing newly

ordinance or regulations in violation of this
section.
1927 Md. Laws, ch. 520, § 3 (codified as Art. 56, § 171-A).
88 [108 Op. Att’y

revised sections to prior law).7 Finally, a non-substantive code
revision in 1977 adopted the current section numbering, codifying
the preemption provision at TR § 25-101.1 and the list of local
powers at TR § 25-102. 1977 Md. Laws, ch. 14.

C. Primary and Secondary Offenses

As discussed above, officers ordinarily have broad authority
to stop drivers for motor vehicle violations. Williams, 401 Md. at
690-91. And a driver’s consent to a search can be voluntary even
if obtained during a traffic stop. Green, 375 Md. at 614-15. But
legislators can impose stricter limits on searches and seizures—
including traffic stops—than the Constitution (State or federal)
requires. See 107 Opinions of the Attorney General 153, 189-90
(2022) (concluding that, even if vehicle searches based on the odor
of cannabis would be constitutional, the General Assembly could
prohibit such searches); see also CP § 1-211 (limiting law
enforcement officers’ authority to conduct stops and searches
based solely on the odor of cannabis).

One potential statutory limit on officers’ authority to stop
vehicles is the designation of certain motor vehicle offenses as
“secondary.” A secondary violation is conduct that, although
unlawful, does not—by itself—allow an officer to initiate a traffic
stop or issue a citation. See, e.g., Christi Schofield, Comment,
Texas, Are We There Yet?, 15 Tex. Tech Admin. L.J. 399, 410
(2014) (discussing status of texting while driving as a primary or
secondary offense). The officer may only issue a citation for a
secondary offense if they have already stopped the driver for a
“primary offense” (meaning any offense that has not been
designated as secondary). Id.

The Maryland Vehicle Law expressly designates certain
traffic offenses as secondary offenses. For example, the Vehicle
Law prohibits driving “with any object, material, or obstruction
hanging from the rearview mirror that interferes with the clear view
of the driver through the windshield.” TR § 21-1104(c)(3). But a

7
The 1970 version retained prior language providing local
governments power to “[r]egulat[e] the standing or parking of vehicles”
even though the most recent Uniform Vehicle Code revision referred to
“[r]egulating or prohibiting stopping, standing or parking.” Uniform
Vehicle Code § 15-102(a)(1) (1968 rev.) (emphasis added). The word
“stopping” was later added to the Maryland provision as part of non-
substantive code revision in 1977; the Revisor’s Note stated that its
omission had been an “oversight.” 1977 Md. Laws, ch. 14 (Revisor’s
Note to TR § 25-102).
Gen. 81] 89

“police officer may enforce this [prohibition] only as a secondary
action when the police officer detains a driver of a motor vehicle
for a suspected violation of another provision of the Code.” TR
§ 21-1104(c)(3)(ii). The Vehicle Law also establishes secondary-
offense status for driving with a partly obscured license plate, TR
§ 13-411(c), violating passenger restrictions on provisional license
holders, TR § 21-1123, driving without headlights in rainy
conditions, TR § 22-201.2, and failure to wear a seatbelt by a
passenger over 16 in the back seat, TR § 22-412.3(c)(3). All of
these remain traffic violations, but they do not, standing alone,
provide a basis for an officer to stop a vehicle or cite a driver.

D. The STEP Act

The STEP Act is a bill pending before the Montgomery
County Council. The bill seeks to reduce racial disparities in traffic
enforcement while promoting traffic safety. Bill No. 12-23,
Montgomery County Council (Feb. 28, 2023) (“STEP Act”)
(proposed Montgomery County Code § 35-27(a)). The STEP Act
would make two major changes to MCPD officers’ traffic
enforcement authority. First, it would designate several offenses
under the Motor Vehicle Law as secondary offenses, beyond those
already identified as secondary by the Vehicle Law itself. Id.
(proposed § 35-27(c), (d)). Second, it would limit the ability of
MCPD officers to request consent to search during traffic stops. Id.
(proposed § 35-27(e)). The bill would also impose reporting
requirements and prohibit collective bargaining over the subjects it
covers. Id. (proposed §§ 33-80, 35-28). There is an express
severability clause. Id. (proposed § 35-29).
The secondary-offense provisions are found in proposed new
sections § 35-27(c) and (d) of the Montgomery County Code. The
STEP Act would designate as a secondary offense: Any offense
under Title 13 of the Transportation Article, relating to vehicle
titles, registration, and license plates; any offense under Title 16,
relating to driver’s licenses; any offense under Title 17, relating to
required insurance; fourteen enumerated provisions of Title 22,
relating to vehicle equipment;8 and §§ 21-203(c) and 21-503,
8
Specifically: driving a vehicle in an unsafe condition or with
improper equipment (§ 22-101(a)); driving without headlights in low-
visibility conditions (§ 22-201.1); driving without headlights while
operating windshield wipers due to low visibility (§ 22-201.2) (which is
already a secondary offense under State law); driving a vehicle that does
not have at least two headlamps (§§ 22-203(b) and 22-226(a)); driving a
vehicle that does not have the rear license plate illuminated
90 [108 Op. Att’y

which prohibit jaywalking (collectively, the “covered provisions”).
STEP Act (proposed § 35-27(c)). The covered provisions together
accounted for around 10–20% of all traffic stops by the MCPD in
2021.9 If the STEP Act were enacted, an MCPD officer could not
“stop or detain a person operating a motor vehicle, solely for a
suspected violation of” one of the covered provisions. Id.

Under the STEP Act, an officer could still issue a citation for
a secondary offense (under one of the covered provisions) after
stopping a driver for a primary offense. Even then, however, an
officer could not cite a driver for a first violation of one of the
covered provisions but rather would be required to give a verbal or
written warning. STEP Act (proposed § 35-27(d)).

The second major topic of the STEP Act is searches during
traffic stops—specifically, officers’ ability to request consent to
search. Under the bill, an officer conducting a traffic stop could
“only ask for permission to conduct a consent search of a person or
vehicle if reasonable suspicion or probable cause for a criminal
offense arises during the stop.”10 STEP Act (proposed § 35-27(e)).

(§ 22-204(f)); driving a vehicle with inadequate stop lamps or turn signal
lamps (§§ 22-206 and 22-219(a)); driving a vehicle that does not have
lamps of the required colors (§ 22-209); driving a vehicle that does not
have required rear reflectors (§ 22-210(c)); driving a vehicle with lamps
that project “glaring or dazzling light” (§ 22-219(g)); using high beams
when approaching another vehicle (§ 22-223); driving a vehicle with
window obstructions (§ 22-404(a)); and driving a vehicle without safety
glass or with window tints that are too dark (§ 22-406). The bill clarifies
that notwithstanding the bill’s designation of various headlight-related
offenses as secondary, an officer would still be able to stop a vehicle that
does not have at least one front and rear light illuminated. STEP Act
(proposed § 35-27(c)(2)(O)).
9
In 2021, violations of Title 13 (registration and license plates)
accounted for 9.08% of all traffic stops by the MCPD; violations of Title
16 (driver’s licenses) for 1.72%; and equipment violations under Title 22
for 10.19% (although the data lump all equipment violations together, so
there is no data on the number of traffic stops for the specific Title 22
provisions covered by the STEP Act). See Data Dashboard (enter
“Montgomery County Police Department” for “Agency” and “2021” for
“Year”). There was no data on traffic stops under Title 17.
10
The STEP Act would also provide that an officer may not extend a
traffic stop beyond its original purpose unless there is reasonable
suspicion of another crime. STEP Act (proposed § 35-27(e)(1)). Other
than eliminating consent as a basis for extending a stop, this is consistent
with what the Fourth Amendment and Article 26 already require. See
Ferris, 355 Md. at 372.
Gen. 81] 91

The STEP Act would thus eliminate “investigatory” traffic stops in
which an officer requests consent to search for evidence of crimes
beyond the motor vehicle offense that authorized the stop, without
particularized suspicion of the driver or vehicle at issue. See OLO
Report at 77. This rule would apply to all MCPD traffic stops, not
just traffic stops where a secondary offense is involved. See STEP
Act (proposed § 35-27(e)).

The STEP Act limits its coverage to the MCPD. It would not
affect traffic stops by the State Police, municipal police, and other
law enforcement agencies. STEP Act (proposed § 35-26(a))
(defining “police officer” as “a sworn officer employed by the
County”). An officer conducting a traffic stop or search in
violation of the STEP Act would be subject to discipline. Id.
(proposed § 35-27(f)).

II
Analysis

You have asked whether the Maryland Vehicle Law would
preempt the proposed STEP Act. Preemption occurs when State
law precludes a local government from enacting a measure that
would otherwise be within the local government’s power.
Preemption may result from the express terms of a State statute,
may be implicit in the comprehensiveness of a State statute’s
coverage, or may occur when a local law directly conflicts with
State law. See, e.g., 101 Opinions of the Attorney General 35, 55
(2016). As we will explain, the Maryland Vehicle Law expressly
preempts local governments from making law on any subject the
Vehicle Law covers. And the Vehicle Law covers the subject of
primary versus secondary offenses: it establishes a default rule of
primary enforcement by empowering officers to issue a citation for
any Vehicle Law offense, while mandating secondary enforcement
for some specific offenses. Because the General Assembly has
addressed the issue, local legislation cannot make different
determinations on which traffic offenses should be primary and
which secondary. But because the Vehicle Law says nothing about
searches during traffic stops, it would not preempt the STEP Act’s
limitations on consent searches. Nor would those limitations on
searches conflict with any provision of the Vehicle Law.

A. General Principles of Preemption

Montgomery County has adopted the charter home rule form
of government. See generally Md. Const., Art. XI-A. This status
grants the county broad authority to enact local laws. See, e.g.,
92 [108 Op. Att’y

Montgomery Citizens League v. Greenhalgh, 253 Md. 151, 160-62
(1969). But a charter county’s power has limits. Even a local law
that is otherwise within the county’s power must yield if State law
preempts it. See, e.g., Edwards Sys. Tech. v. Corbin, 379 Md. 278,
296-97 (2004).
State law can preempt local law in one of three ways. E.g.,
Worton Creek Marina, LLC v. Claggett, 381 Md. 499, 512 (2004).
First, express preemption occurs when a State statute explicitly
precludes local governments from making law in a certain area. 98
Opinions of the Attorney General 60, 88 (2013). We interpret
express preemption provisions under the normal rules of statutory
construction. See, e.g., 75 Opinions of the Attorney General 308,
311-12 (1990). Under those rules, our primary objective is to
determine and effectuate the intent of the General Assembly,
beginning with the ordinary meaning of the language used,
considered in context, and considering other sources of meaning,
such as legislative history and the statute’s general purpose. E.g.,
107 Opinions of the Attorney General 196, 203 (2022).

The second form of preemption is implied preemption. “State
law can preempt local ordinances by implication when ‘the
ordinance deals with an area in which the General Assembly has
acted with such force that an intent to occupy the entire field must
be implied.’” Board of County Comm’rs v. Perennial Solar, LLC,
464 Md. 610, 619 (2019) (quoting Howard County v. Potomac
Elec. Power Co., 319 Md. 511, 522 (1990)). But a statute with an
express preemption provision is unlikely to implicitly preempt, in
this way, more than it expressly preempts. See Browning-Ferris,
Inc. v. Anne Arundel County, 292 Md. 136, 153 (1981); see also
107 Opinions of the Attorney General 74, 83-84 (2022) (discussing
this point in the context of federal-state preemption).
Third, conflict preemption occurs when a local law directly
conflicts with State law. Maryland courts have recognized two
sub-types of conflict preemption. First, a “verbal” conflict, also
known as “prohibit-permit” conflict, exists when the local law
would authorize something State law prohibits or would prohibit
something State law expressly authorizes. 98 Opinions of the
Attorney General at 91; Worton Creek, 381 Md. at 513. Second, a
“functional” conflict exists when the impact of the local law
Gen. 81] 93

interferes with the State law’s function. 96 Opinions of the
Attorney General 139, 144 (2011).11
B. The STEP Act’s Secondary-Offense Provisions

We first consider whether the Vehicle Law would preempt the
STEP Act’s secondary-offense provisions. Under the Vehicle
Law, a local government may not “make or enforce any local law,
ordinance, or regulation on any subject covered by the Maryland
Vehicle Law” except as expressly authorized. TR § 25-101.1(b)(3);
accord TR § 25-101.1(c)(1). Our Office has described this
provision as representing “some of the most far-reaching
preemption in State law.” Letter from Kathryn M. Rowe, Assistant
Attorney General, to Del. Brooke E. Lierman, at 1 (Oct. 10, 2018);
see also 93 Opinions of the Attorney General 126, 134 (2008)
(characterizing the Vehicle Law’s express preemption provision as
especially “open-ended”).

To determine whether the Vehicle Law preempts a local law
under § 25-101.1, we must answer three questions: First, is the
local measure at issue a “local law, ordinance, or regulation”?
Second, does it address a “subject covered by the Maryland Vehicle
Law”? Third, does any other State law “expressly authorize[]” the
measure? If the measure is a “local law, ordinance, or regulation”
on a “subject covered by the Maryland Vehicle Law,” and no other
State law expressly authorizes it, the local enactment is preempted.
Answering the first question is straightforward: if enacted by
the County Council, the STEP Act would clearly be a “local law”
or “ordinance” within the meaning of TR § 25-101.1. The other
two questions require more detailed analysis.

1. Subject Covered by the Maryland Vehicle Law

As to the second question, our opinion is that the STEP Act’s
secondary-offense provisions address a “subject covered by the
Maryland Vehicle Law”: the determination of which motor vehicle
offenses are primary and which are secondary.

11
Federal law also recognizes “obstacle” or “frustration of purpose”
preemption, when a state law “stands as an obstacle to the
accomplishment and execution of the full purposes and objectives of
Congress.” E.g., Arizona v. United States, 567 U.S. 387, 399 (2012)
(quoting Hines v. Davidowitz, 312 U.S. 52, 67 (1941)). But Maryland
courts have so far declined to import this doctrine into the State versus
local law context. E.g., County Council of Prince George’s County v.
Chaney Enters. Ltd. P’ship, 454 Md. 514, 541 n.19 (2017).
94 [108 Op. Att’y

Several of our prior opinions have considered whether
particular local laws addressed subjects covered by the Vehicle
Law. For example, in one opinion, we concluded that when State
law required minors (and only minors) to wear motorcycle helmets,
Baltimore City could not impose the same requirement on adults,
because the Vehicle Law covered the subject of “safety equipment
required of motorcycle operators,” 65 Opinions of the Attorney
General 483, 484, 486-87 & n.7 (1980). Later, our Office
concluded in a different opinion that a city ordinance could address
charitable and employment solicitations from sidewalks, from
vehicles, and in parking lots, where the Vehicle Law addressed
only solicitation by pedestrians standing in the roadway. 93
Opinions of the Attorney General 31, 33, 36-37 (2008). Another
opinion concluded that a city could regulate parking on private
property with the property owner’s consent because the Vehicle
Law only regulates parking on private property without the
property owner’s consent. 73 Opinions of the Attorney General
252, 254-55 (1988).12

As these opinions illustrate, the level of generality at which
the Vehicle Law’s preempted “subjects” should be defined is not
always clear. Our 2008 opinion on roadway solicitation, for
example, would presumably have reached the opposite result if we
had defined the covered “subject” as solicitation in a roadway
rather than solicitation by pedestrians in a roadway; this would
have preempted the local ban on solicitation from vehicles.
Similarly, our 1980 opinion on motorcycle helmets would likely
have reached the opposite result if it had defined the covered
subject as “motorcycle safety equipment required of minors,”
thereby saving Baltimore City’s adult helmet requirement from
preemption.

Even though it may not always be clear how broadly (or
narrowly) to define the “subjects” covered by the Vehicle Law, it
is clear that when a local law addresses a matter that specific
provisions of the Vehicle Law also directly address, the local law

12
In Mayor & City Council of Baltimore v. Hart, 395 Md. 394 (2006),
Maryland’s highest court held that the Vehicle Law did not preempt a
Baltimore City Police Department general order setting rules for
emergency vehicles that were stricter than State law, id. at 406.
However, for reasons that are not clear from the opinion or briefing, the
question of express preemption under TR § 25-101.1 was not presented
in Hart. See id. at 406-10 (discussing conflict preemption only). It is
also possibly relevant that Hart involved a departmental order rather than
a “local law, ordinance, or regulation.” See id. at 404; see also infra Part
II.B.3.
Gen. 81] 95

will be preempted. The level of generality problem has arisen only
when a local law has addressed something that the Vehicle Law
does not directly address—such as motorcycle helmets for adults
or solicitation from cars—but that was arguably related to, and thus
possibly part of the same broader “subject” as, a matter the Vehicle
Law did address. But there is no question that the Vehicle Law
would preempt a local law on a subject the Vehicle Law directly
speaks to. See, e.g., 58 Opinions of the Attorney General 462, 464
(1973) (concluding that a local ordinance, intended to prevent
debris from falling off trucks, was preempted because the Vehicle
Law also had a provision requiring the securing of truck loads).

Here, the Vehicle Law directly addresses which offenses are
primary and which are secondary through a rule that applies to all
offenses under the Vehicle Law. More specifically, § 26-201 of
the Transportation Article establishes that an officer may issue a
citation for a violation of any Vehicle Law provision, if the officer
has probable cause to believe the person has committed or is
committing the violation. TR § 26-201(a). The General Assembly
added this provision in 1977 to make explicit a power that had
previously been implicit. 1977 Md. Laws, ch. 186; Commission to
Revise the Annotated Code, Report on S.B. 501, 1977 Leg., Reg.
Sess., at 4 (Feb. 22, 1977). Although the statute refers only to
citations and not explicitly to traffic stops, the authority to issue a
citation for a motor vehicle offense implies the authority to make a
traffic stop, because the statute requires that the citation be issued
to and acknowledged by the driver. See TR §§ 26-201(b), 26-203.
And more importantly, by authorizing an officer to issue a citation
for any motor vehicle offense without regard to whether another
offense has been committed, TR § 26-201 provides for primary
enforcement of all motor vehicle offenses. If an officer can cite a
driver for a given offense, without more, that offense is necessarily
primary. The Vehicle Law thus addresses the subject of primary
versus secondary enforcement of the motor vehicle laws by
establishing a general rule of primary enforcement.

As exceptions to that general rule, the General Assembly has
expressly designated some specific motor vehicle violations as
secondary. See, e.g., TR § 21-1104(c)(3) (driving with an object
hanging from the rearview mirror); TR § 13-411(c)(2) (driving
with a frame or border partially obscuring the license plate); see
also supra Part I.C (listing other examples). Typically, an officer
may enforce one of these provisions only after stopping a driver for
a suspected violation of a different provision. E.g., TR
§ 21-1104(c)(3)(ii). So, for example, an officer could not stop or
cite a driver who was driving with an object hanging from the
96 [108 Op. Att’y

rearview mirror but otherwise obeying the law. If the driver then
ran a red light, however, an officer could stop the driver and cite
them for both offenses. The General Assembly’s express
categorization of certain offenses as secondary confirms that the
Vehicle Law covers the subject of which motor vehicle offenses
are primary and which are secondary. Reading the Vehicle Law as
a whole, as we are required to do, e.g., 105 Opinions of the Attorney
General 3, 16 (2020), these secondary-offense provisions are best
read as exceptions to the general rule of primary enforcement
established by TR § 26-201.

Indeed, under standard principles of statutory interpretation,
the General Assembly’s establishment of these specific exceptions
indicates an intent that the general rule should apply in all cases not
expressly excepted. See, e.g., 85 Opinions of the Attorney General
80, 83 (2000) (noting that “exceptions are strictly construed”);
Leppo v. State Highway Admin., 330 Md. 416, 423 (1993) (“When
the legislature has expressly enumerated certain exceptions to a
principle, courts normally should be reluctant thereafter to create
additional exceptions.” (quoting Ferrero Constr. Co. v. Dennis
Rourke Corp., 311 Md. 560, 575 (1988)); Department of Motor
Vehicles v. Greyhound Corp., 247 Md. 662, 668 (1967) (“By
making these two items the sole exceptions, the statute is as plain
as if it had listed all of the [items] not included in the exceptions.”).
And, consistent with that understanding, where the General
Assembly has chosen to make particular offenses secondary, the
legislative history of those enactments expressly recognized that
“[e]xcept as otherwise specified, violations of the Maryland
Vehicle Law are subject to primary enforcement.” Fiscal & Policy
Note, H.B. 1335, 2017 Leg., Reg. Sess., at 1; accord Fiscal &
Policy Note, S.B. 859, 2020 Leg., Reg. Sess., at 2 (same). Thus,
read as a whole, the Vehicle Law addresses the subject of primary
versus secondary enforcement: it establishes a rule that, unless the
Vehicle Law has expressly designated a motor vehicle offense as
secondary, the offense is subject to primary enforcement.

Especially illustrative are the instances where the General
Assembly has redesignated a formerly primary offense as
secondary. 2020 Md. Laws, ch. 107 (frame or border partly
obscuring license plate); 2017 Md. Laws, ch. 756 (object hanging
from rearview mirror). In each of these cases, a major purpose of
the change was to reduce racially disparate traffic enforcement.
Hearing on H.B. 200 Before the House Env’t & Transp. Comm.,
2020 Leg., Reg. Sess., at 1:08:10-1:09:50 (Feb. 13, 2020) (“H.B.
200 Hearing”) (statement of Del. Fisher); Hearing on H.B. 1335
Before the House Env’t & Transp. Comm., 2017 Leg., Reg. Sess.,
Gen. 81] 97

at 2:29:40-2:30:30 (Mar. 9, 2017) (“H.B. 1335 Hearing”)
(statement of Del. Wilkins). But, in each case, the Legislature
chose to establish secondary enforcement for only some of the
conduct the provision covered and keep primary enforcement for
the rest. As to license plates, for instance, the Legislature provided
secondary offense status only for objects obscuring the frame or
border of a license plate and left primary enforcement in place for
material covering the actual plate number. See 2020 Md. Laws, ch.
107. Similarly, as to windshield obstruction, the General Assembly
downgraded driving with material hanging from the rearview
mirror to a secondary offense, while retaining primary enforcement
for other instances where an object obstructs a driver’s view
through the windshield. See 2017 Md. Laws, ch. 756.

In other instances, legislative proposals to make particular
offenses secondary have failed. For example, when the General
Assembly in 2009 passed legislation to prohibit texting while
driving, see 2009 Md. Laws, ch. 194 (enacting TR § 21-1124.1),
the Senate rejected a proposed floor amendment that would have
made texting while driving a secondary offense, see Amend. No.
463122/1, S.B. 98, 2009 Leg., Reg. Sess., with the understanding
that if the amendment were rejected the offense would be primary,
see Senate Floor Proceedings No. 43, 2009 Leg., Reg. Sess., at
23:00-23:48 (Mar. 13, 2009) (statement of Sen. Zirkin). This
further supports the view that the Vehicle Law establishes a general
rule of primary enforcement for motor vehicle offenses and that
preservation of that general rule, for offenses not explicitly
declared secondary, is intentional on the part of the Legislature.
Balancing the benefits and costs of secondary enforcement for a
given offense is a policy judgment, and the Vehicle Law’s express
preemption provision reserves that policy judgment to the General
Assembly.
Perhaps if the Vehicle Law only designated certain offenses
as secondary, and was otherwise silent as to how the traffic laws
are to be enforced, the case for preemption would be weaker. But
the combination of the general rule allowing police officers to cite
drivers for any Vehicle Law offense—which indicates that such
offenses are generally subject to primary enforcement—and the
specific exemptions for situations where the Legislature has
determined secondary enforcement to be appropriate, causes us to
conclude that the Maryland Vehicle Law covers the subject of
primary versus secondary enforcement of motor vehicle offenses.
Thus, a local law may not address that subject absent express
authorization by the General Assembly.
98 [108 Op. Att’y

2. Express Authorization by Other State Law

The third question under the Vehicle Law’s express
preemption provision is whether, even if the STEP Act’s
secondary-offense provisions involve a subject covered by the
Vehicle Law, there is nonetheless a separate express authorization
for local governments to legislate on that subject. The Vehicle Law
does, alongside its broad preemption provision, expressly reserve
certain powers to localities. TR § 25-102(a). We thus need to
consider whether any of those powers would authorize the STEP
Act’s secondary-offense provisions.

The list of enumerated local powers in § 25-102(a) dates back
to 1943. Before that year, the Vehicle Law had contained—
alongside the general preemption provision enacted in 1927—a
provision authorizing local governments to promulgate
“reasonable traffic regulations.” Md. Ann. Code, Art. 56, § 145
(1939). As part of its 1943 revision to the Vehicle Law, which
sought to “promot[e] greater uniformity,” 1942 Report at 8, the
General Assembly repealed that broad power. See 1943 Md. Laws,
ch. 1007. In its place, the Legislature enacted a list of six specific
local powers (copied almost verbatim from the 1938 Uniform
Vehicle Code) and provided that the Vehicle Law “shall not be
deemed to prevent local authorities” from exercising those powers.
Compare 1943 Md. Laws, ch. 1007 (enacting Art. 66 ½, § 135),
with Uniform Vehicle Code, Uniform Act Regulating Traffic on
Highways § 28, at 5 (1938 rev.).13

One of the reserved powers is “regulating or prohibiting the
stopping, standing, or parking of vehicles.” TR § 25-102(a)(1)
(emphasis added). On its face, this provision might appear to cover
traffic “stops” by police. But “stop” is a defined term under the

13
The six local powers enumerated in 1943 were: “(1) Regulating the
standing or parking of vehicles; (2) Regulating traffic by means of police
officers or traffic control devices; (3) Regulating or prohibiting
processions or assemblages on the highways; (4) Designating particular
highways as one way highways and requiring that all vehicles thereon be
moved in one specific direction; (5) Regulating the speed and weight of
vehicles in public parks; (6) Designating any intersection as a stop
intersection requiring all vehicles to stop at one or more entrances to such
intersections.” 1943 Md. Laws, ch. 1007 (enacting Art. 66 ½, § 135).
These provisions are now codified, with minimal changes, at TR
§ 25-102(a)(1)-(6). The General Assembly has since added further items
to the list, but the new items are not substantially different in character
from the original six; all essentially relate to the control of traffic on
roads under the local government’s jurisdiction. See TR § 25-102(a).
Gen. 81] 99

Vehicle Law, TR § 11-162, and when used in a “prohibitory
sense”—the sense in which § 25-102(a)(1) uses it—the term “stop”
excludes instances where a vehicle stops “in compliance with the
directions of a police officer,” TR § 11-162(2). Also, the context
in which the word “stopping” is used in § 25-102(a)(1)—together
with “standing” and “parking”—implies that the provision is
concerned with where and when a driver may stop or park their
vehicle safely, not with officer-initiated traffic stops. See Shivers
v. State, 256 Md. App. 639, 664 (2023) (noting that in statutory
interpretation “the meaning of a word is or may be known from the
accompanying words” (quoting Emmert v. Hearn, 309 Md. 19, 25
(1987)).

The provision’s history accords with that understanding.
Section 25-102(a)(1) originally omitted the word “stopping,” even
though that word had appeared in the Uniform Vehicle Code
provision on which the Maryland provision was modeled.
Compare 1970 Md. Laws, ch. 534 (enacting Art. 66 ½,
§ 15-102(a)(1)), with Uniform Vehicle Code § 15-102(a)(1), at 230
(1968 rev.). The word “stopping” was added seven years later
during the code revision process to correct this “oversight.” 1977
Md. Laws, ch. 14 (Revisor’s Note to TR § 25-102). Because the
code revision process generally is not intended to make substantive
changes to the law, this history implies that the General Assembly
did not see the addition of “stopping” alongside “standing” and
“parking” as changing the scope of the power. See, e.g.,
Comptroller v. Blanton, 390 Md. 528, 538-39 (2006).

Local governments also have the power of “[r]egulating
traffic by means of police officers or traffic control devices.” TR
§ 25-102(a)(2). This provision, in our view, recognizes that local
governments may employ police officers to direct traffic and
control the movement of vehicles on the roadway, as necessary to
ensure safe and efficient traffic flow. But we do not think it
empowers local authorities to revise the General Assembly’s
determination on whether a traffic offense is primary or secondary.

To begin, we note that the provision speaks of “regulating
traffic.” “Traffic” means the physical movement of vehicles on a
highway. See TR § 11-166. So “regulating traffic” most naturally
means directing traffic, i.e., controlling the movement of vehicles
and traffic flow. The provision recognizes that local governments
may regulate traffic in two ways—“by means of” either police
officers or traffic control devices, TR § 25-102(a)(2), with the latter
referring to traffic lights, stop signs, and the like, TR § 11-167.
This, again, suggests that § 25-102(a)(2) contemplates police
100 [108 Op. Att’y

officers acting in a role similar to a traffic light or stop sign—
directing traffic in the ordinary course of its movement. The other
provisions enacted alongside § 25-102(a)(2) in 1943 similarly
relate to the control of physical traffic movement, akin to the
placement of traffic signals, such as designation of a street as a one-
way street or of an intersection as a four-way stop. See 1943 Md.
Laws, ch. 1007. As Maryland courts often say, “the meaning of the
plainest language is controlled by the context in which it appears.”
E.g., Elsberry v. Stanley Martin Cos., 482 Md. 159, 181 (2022)
(quoting Building Materials Corp. of Am. v. Board of Educ., 428
Md. 572, 585 (2012)). Here, the context indicates that
§ 25-102(a)(2)’s reference to “regulating traffic by means of police
officers” addresses what it seems, at first glance, to address—local
authority to have police officers control and direct traffic
movement.

But even if § 25-102(a)(2)’s coverage is broader than just that,
we cannot identify a reading of that provision that is both broad
enough to encompass the authority to redesignate primary offenses
as secondary and also consistent with the provision’s text, context,
and history. That is, we doubt that the General Assembly intended
to enable localities to alter the legislative judgment that “[e]xcept
as otherwise specified, violations of the Maryland Vehicle Law are
subject to primary enforcement.” E.g., Fiscal & Policy Note, H.B.
1335, 2017 Leg., Reg. Sess. at 1. A police officer’s statutory
authorization to issue a citation for any Maryland Vehicle Law
offense, except those explicitly designated as secondary offenses
by the General Assembly, reflects that general rule of primary
enforcement. See TR § 26-201. Again, we interpret statutory
schemes, as far as possible, to form a harmonious whole. E.g.,
Lockshin v. Semsker, 412 Md. 257, 276 (2010). For example, in a
prior opinion, we concluded that even though local governments
have the express authority to regulate parking, they cannot adopt
procedures for handling parking violations that differ from the
procedure in State law. 78 Opinions of the Attorney General 263,
264-65 (1993). Here, too, we think the exercise of any power under
§ 25-102(a)(2) must be consistent with the overall statutory scheme
of the Vehicle Law.14
14
Our reading of § 25-102(a)(2) is also consistent with the principle
that a statute should be construed so that none of its language “is
rendered surplusage, superfluous, meaningless, or nugatory.” E.g., Rowe
v. Maryland Comm’n on Civil Rights, 483 Md. 329, 342 (2023) (quoting
Mayor & Town Council of Oakland v. Mayor & Town Council of
Mountain Lake Park, 392 Md. 301, 316 (2006)). In particular,
§ 25-102(a)(1) and § 25-102(a)(2) address distinct topics under our
Gen. 81] 101

Authority from other jurisdictions supports our view as well.
As noted above, § 25-102(a)(2)’s language comes from the
Uniform Vehicle Code. Other states have interpreted their parallel
provisions consistent with our view that § 25-102(a)(2) authorizes
localities to use police to regulate the movement of traffic in
accordance with law but not to alter the rules of traffic enforcement
themselves. For example, the Minnesota Supreme Court held that
the effect of a provision with near-identical language “is only to
authorize a city to direct the movement of vehicles on the
roadway.” State v. Kuhlman, 729 N.W.2d 577, 582 (Minn. 2007);
see also id. at 582-84 (holding that state law preempted city attempt
to authorize red light cameras). Similarly, the Florida Supreme
Court in Masone v. City of Aventura, 147 So.3d 492, 497 (Fla.
2014), concluded that the purpose of its own parallel statutory
language was to allow local governments to control the movement
of traffic but not to alter the statutory rules of traffic enforcement.
In contrast, we know of no jurisdiction that has interpreted this
provision to authorize a locality to redesignate a primary traffic
violation as secondary.

3. The Role of Enforcement Discretion

One might argue that our conclusion clashes with the
enforcement discretion normally vested in police departments and,

interpretation: § 25-102(a)(1) covers rules for where drivers can stop or
park their vehicles, and § 25-102(a)(2) deals with the control of active
traffic flow by official authority, namely officers or traffic signals. One
might also argue that, unless § 25-102(a)(2) authorizes some subject
matter that would otherwise be preempted, § 25-102(a)(2) serves no
purpose. But the provisions of § 25-102(a) may have been intended
primarily for the avoidance of doubt, that is, to eliminate any suggestion
that the listed subjects are preempted. Indeed, § 25-102(a) seems to
cover at least some matters that would not have been preempted even
absent § 25-102(a)’s enactment. For example, § 25-102(a)(12)
authorizes localities to “[a]dopt[] any other traffic regulations as
specifically authorized in the Maryland Vehicle Law,” which (because it
merely refers to authorization granted elsewhere) would necessarily be
surplusage under a strict application of the canon. Finally, it is an equally
well-established rule of statutory interpretation that interpreters should
neither “add nor delete language so as to reflect an intent not evidenced
in the plain and unambiguous language of the statute,” nor should they
“construe a statute with forced or subtle interpretations that limit or
extend its application.” E.g., Rowe, 483 Md. at 342 (quoting Lockshin,
412 Md. at 275). As we have explained, § 25-102(a)(2) speaks only to
“regulating traffic,” and we think it would require a “forced”
interpretation to stretch that language to encompass the designation of
traffic violations as primary or secondary.
102 [108 Op. Att’y

thus, in the local governments that employ those police
departments. No police department enforces all of the traffic laws
all of the time—as anybody who has driven on a highway knows
from observing that the speed of traffic is usually five or ten miles
per hour above the speed limit. Generally, the decision whether to
stop or detain a driver for a motor vehicle offense is a matter of the
individual officer’s discretion, even when the officer has observed
a probable violation. See Ashburn v. Anne Arundel County, 306
Md. 617, 624 (1986). Indeed, current departmental policy of the
MCPD explicitly grants officers “discretion in the enforcement of
traffic laws” and states that “[a] written warning is appropriate . . .
where a minor equipment defect is apparent.” MCPD, FC No.
1000, Traffic Management System, § VIII(A)-(B) (July 1, 2022).

It also seems clear that a local government generally has
authority to set internal operating rules for its own agencies,
including the local police department. “The authority to establish
a police force would be futile if it did not carry with it, at least by
implication, the authority to enact reasonable rules for the effective
administration of the force . . . .” 16A McQuillin: The Law of
Municipal Corporations § 45:14 (3d ed., June 2023 update). The
question arises, then, why a local legislative body cannot adopt
something akin to the STEP Act as a way of setting rules for the
exercise of enforcement discretion for its own local police
department.

It may well be that, as a general matter, the County Council
could by ordinance set enforcement priorities for the county police
department. But whatever legislative authority the County Council
might possess is overridden in this specific area by the General
Assembly’s decision to preempt “local law[s]” and “ordinance[s]”
addressing “subject[s]” covered by the Vehicle Law. TR
§ 25-101.1(b)(3). In this particular area of motor vehicle law—that
is, whether an offense is primary or secondary—the Legislature has
decided as a policy matter that the need for statewide uniformity
outweighs local governments’ legislative autonomy. See 65
Opinions of the Attorney General at 486. Simply put, then, the
County Council may not legislate on a subject the General
Assembly has fenced off, even when it would have full power to
act but for the preemption statute. See 101 Opinions of the Attorney
General at 55-57 (concluding that preemption limits a county
governing body’s power to place conditions on appropriations in
the context of public library funding).

We also express no opinion about whether the county police
department could adopt, on its own authority, an internal policy
Gen. 81] 103

resembling the STEP Act. The MCPD currently has internal
policies, issued by the Chief of Police, on a variety of subjects. See
generally MCPD, Department Policies, https://www.montgomery
countymd.gov/pol/resource/policies.html (last visited Sept. 13,
2023). Express preemption under TR § 25-101.1 applies only to a
“local law, ordinance, or regulation,” and there is at least a question
as to whether an executive branch agency’s internal policy, which
is subject to change at any time and merely communicates how the
agency plans to exercise its discretion, would qualify as a local law,
ordinance, or regulation, especially when the policy might not need
to be promulgated as a formal regulation under the applicable
administrative procedure statute. Cf. Montgomery County Code
§ 35-3(c) (indicating that county administrative procedure law
governs the adoption of police “regulations” but not “orders”). In
any event, we need not decide whether a police department could
adopt such a policy to answer the question that you have asked. We
conclude only that a local legislative body may not designate a
traffic offense as secondary when State law has not done so.15

C. The STEP Act’s Consent-Search Provision

The STEP Act would also prohibit an MCPD officer from
requesting consent to search, during a traffic stop, unless
reasonable suspicion or probable cause “arises during the stop.”
STEP Act (proposed § 35-27(e)(2)). For the reasons explained
below, the Vehicle Law’s express preemption provision would not
cover this aspect of the STEP Act, because the Vehicle Law does
not address the conditions under which an officer may search a
vehicle, or its occupants, during a traffic stop. Nor does the
Vehicle Law establish implied field preemption beyond the scope
of its express preemption clause. And a restriction on searches
during stops would not conflict with any provision of the Vehicle
Law. Accordingly, the Vehicle Law would not preempt the STEP
Act’s consent-search provision.16

15
Because we conclude that the STEP Act’s secondary-offense
provisions would be expressly preempted, we need not consider whether
they would be subject to implied or conflict preemption.
16
Your opinion request asked only whether the Vehicle Law would
preempt the STEP Act. We thus limit our preemption analysis to the
Vehicle Law. We also note that the STEP Act’s provision precluding
collective bargaining on the matters covered by the STEP Act (proposed
§ 33-80) would not be preempted by the Vehicle Law for similar reasons
to those discussed here: the Vehicle Law does not address collective
bargaining or require collective bargaining on any particular topic, so no
form of preemption would apply.
104 [108 Op. Att’y

1. Express Preemption

As we have explained, express preemption under the Vehicle
Law applies only when a local law, ordinance, or regulation
addresses a “subject covered by the Maryland Vehicle Law.” TR
§ 25-101.1(b)(3). Although the Vehicle Law’s enforcement
provisions cover procedures for citation, arrest, and prosecution for
motor vehicle offenses, see generally TR §§ 26-201 to 26-412,
nothing in the Vehicle Law prescribes the circumstances under
which an officer may, or may not, conduct a search during a traffic
stop or otherwise. In short, the Vehicle Law is not the source of an
officer’s authority to search.17 Thus, the Vehicle Law does not
expressly preempt a local law limiting a local police department’s
authority to conduct searches, because searches are “altogether
beyond the purview of the Vehicle Law.” See 71 Opinions of the
Attorney General 400, 404 (1986) (concluding that the Vehicle
Law does not address speed bumps).

2. Implied Preemption

Implied preemption occurs when the “General Assembly has
acted with such force that an intent to occupy the entire field must
be implied.” Perennial Solar, 464 Md. at 619. But we do not think
the Vehicle Law implicitly preempts a field broader than its express
preemption provision. In other words, if a local law is not subject
to the Vehicle Law’s express preemption provision, it is likely not
subject to implied preemption either. Normally, when the General
Assembly specifies the items to which a law will apply, we will
infer that the exclusion of other items was intentional. See 98
Opinions of the Attorney General 3, 12 (2013) (discussing the
canon of construction expressio unius est exclusio alterius, or “the
expression of one thing is the exclusion of another”). That
principle applies to preemption as well. When the General
Assembly has drafted an express preemption provision, it is usually
a reasonable inference that the Legislature considered the breadth
of the field it wanted to preempt and that the express preemption
provision corresponds to that intent. See Browning-Ferris, 292
Md. at 153 (holding that the enactment of a narrower express
preemption provision overrode what had been “a very strong case”
for broader implied preemption). Although we do not foreclose the
possibility that legislative intent could indicate implied preemption
extending beyond the bounds of express preemption within the
17
TR § 25-113 requires law enforcement agencies to gather certain
data on searches during traffic stops and to adopt a policy against race-
based traffic stops that does not affect an officer’s otherwise existing
authority to search, but it does not, itself, grant authority to search.
Gen. 81] 105

context of a particular statutory scheme, we see no evidence of such
an intent here. The Vehicle Law therefore would not implicitly
preempt the STEP Act’s consent-search provision.

3. Conflict Preemption
Conflict preemption is the third and final form of preemption
Maryland law recognizes. The first type of conflict preemption,
and the one Maryland courts most frequently consider, is “verbal”
or “prohibit-permit” conflict. Under this type of conflict
preemption, local law may not permit what State law prohibits, nor
may local law prohibit what State law affirmatively permits. See
Mayor & City Council of Baltimore v. Sitnick, 254 Md. 303, 317
(1969). There is no preemption if State law permits something
simply by not addressing it; rather, State law must affirmatively
authorize an activity before a local law prohibiting that activity will
be preempted. Coalition for Open Doors v. Annapolis Lodge No.
622, Benevolent & Protective Order of Elks, 333 Md. 359, 380
(1994). As we have discussed, the Vehicle Law is silent on
searches; it neither prohibits them, nor expressly permits
them. Accordingly, there would be no verbal conflict between the
Vehicle Law and a local prohibition on consent searches.

The second type of conflict preemption is “functional
conflict.” The courts have not been as clear about what a functional
conflict involves. But, “[i]n general, some element of
irreconcilability or legal inconsistency is required, such that both
the State and local laws cannot be applied together.” 93 Opinions
of the Attorney General at 135. We see no inconsistency or
irreconcilability between the Vehicle Law and the STEP Act’s
consent-search provisions.

The consent-search provision would not create a problem
analogous to any of the situations where courts have found
functional conflicts. See Coalition for Open Doors, 333 Md. at 380
n.39 (citing functional conflict cases). First, the consent-search
provision would not create a situation where there would be
conflicting rules in the same area such that a police officer could
not simultaneously comply with State and local law. See
Montgomery County v. Board of Supervisors of Elections, 311 Md.
512, 517 (1988) (finding functional conflict when State and local
law provided irreconcilable methods of appointing the same
officers). The provision also would not prohibit a local
government from taking action that is required under State law. See
East v. Gilchrist, 296 Md. 368, 373-74 (1983) (finding functional
conflict where local charter prohibited county from spending
106 [108 Op. Att’y

money that State law required it to spend). Nor would it create a
“direct conflict with a State statute regulating the same matter,”
Worton Creek, 381 Md. at 514 (discussing Montgomery County Bd.
of Realtors v. Montgomery County, 287 Md. 101, 109-10 (1980),
in which the Court held that a local tax conflicted with the State’s
scheme for assessment of real property), because, again, the
Vehicle Law does not regulate searches.

We have also suggested that a functional conflict may exist
when a local law interferes with the functioning of a State law. See
98 Opinions of the Attorney General at 91. We would be cautious
about finding a functional conflict on this basis alone, given that
Maryland courts have repeatedly declined to adopt the similar
federal doctrine of obstacle preemption, under which a law is
preempted if it frustrates the purpose of a federal statute. E.g.,
Chaney, 454 Md. at 541 n.19. But even assuming State law can
preempt local law in this way as a general matter, this is not such a
case.

The purpose of the Vehicle Law is to ensure the safe and
efficient movement of traffic, and to prevent crashes and injuries
on roadways. Supra Part I.B. By contrast, the functional effect of
the consent-search provision of the STEP Act is to limit an officer’s
authority to search an already-stopped vehicle. Because these
provisions of the Act would only limit what an officer can do once
the vehicle has already been stopped, their impact on traffic
enforcement would be minimal—given that traffic violations are
meant to be observable before the vehicle has been stopped. When
an officer seeks consent to search a stopped vehicle, despite lacking
any particularized suspicion of a crime, their purpose is usually not
to enforce the traffic laws but to search for evidence of other
crimes, like possession of contraband. See, e.g., LaFave, supra, at
1891-92. Perhaps there might be some circumstances where
evidence of a motor vehicle offense could only be revealed through
a suspicionless consent search, but we think such cases will be
rare. The STEP Act’s consent-search provision thus would not
interfere with the Vehicle Law’s functioning to such a degree as to
be preempted.

III
Conclusion
In our opinion, the Maryland Vehicle Law would preempt a
local law, such as the STEP Act, that would designate a violation
of the Vehicle Law as secondary when State law has not designated
it as such. This is because the determination of which motor
Gen. 81] 107

vehicle offenses are primary, and which are secondary, is a subject
covered by the Vehicle Law. And neither the local power to
regulate “stopping, standing or parking,” TR § 25-102(a)(1), nor
the local power to “regulate traffic by means of police officers,”
TR § 25-102(a)(2), authorizes a local government to redesignate a
Vehicle Law offense from primary to secondary status. On the
other hand, the Vehicle Law would not preempt a local law limiting
a local police officer’s ability to request consent to search during
traffic stops. Because the Vehicle Law does not address the
conditions under which searches are permissible, such a local law
would neither intrude on a subject covered by the Vehicle Law nor
conflict with the Vehicle Law.

Anthony G. Brown
Attorney General of Maryland

Thomas S. Chapman
Assistant Attorney General

Patrick B. Hughes
Chief Counsel, Opinions and Advice