Can a Maryland town legally install speed bumps on its own streets, and could it get sued if someone is hurt by one?

Plain-English summary

A member of the Maryland House of Delegates asked the Attorney General whether a municipality could install "speed bumps," raised pavement features meant to force drivers to slow down, on public streets within town limits, and what liability risk the town would face for doing so.

The Attorney General drew a sharp line based on who controls the road. On State highways running through a municipality, the State Highway Administration has exclusive statutory authority over design, construction, and maintenance, and SHA's own policy is not to install speed bumps anywhere due to safety concerns, so a municipality has no independent authority to put speed bumps on those roads. On a town's own streets, though, the opinion found the Maryland Vehicle Law does not actually address speed bumps at all, since they don't fit the statutory definition of a "traffic control device" (they don't regulate, warn, or guide traffic the way a sign or signal does; they physically slow vehicles), so the Vehicle Law's general preemption of local traffic ordinances does not block a municipality from installing them under its separate, general police power to protect public safety on streets it controls. However, the opinion cautioned that a municipality's duty to keep its streets reasonably safe for travelers is real, and that installing a hazard like a poorly placed or unmarked speed bump could expose a town to liability if someone is injured, so any municipality going this route should study the engineering carefully, place bumps only on lightly traveled, low-speed streets, and post adequate warning signs.

Currency note

This opinion was issued in 1986. Subsequent statutory amendments, court decisions, or later AG opinions may have changed the analysis. Treat this page as historical context, not current legal advice. Verify current law before relying on any specific rule, deadline, or remedy mentioned here.

Common questions

Can a Maryland town put a speed bump on a state highway that runs through town?
No, according to this opinion. The Attorney General concluded that the State Highway Administration has exclusive authority over State highways, including those passing through municipalities, and does not permit speed bumps on any road it controls.

Does Maryland's Vehicle Law let a town install speed bumps on its own local streets?
The opinion found the Vehicle Law neither authorizes nor prohibits speed bumps on municipal streets because they don't meet the statutory definition of a "traffic control device." Instead, a municipality's authority comes from its separate general police power to protect public safety.

Could a town be sued if a speed bump it installed caused an accident?
Potentially, yes. The opinion warned that a municipality has a legal duty to keep its streets reasonably safe and to warn of hazards, so an improperly designed, placed, or unmarked speed bump could expose the town to liability, especially since speed bumps can pose risks to bicycles, motorcycles, and emergency vehicles.

Background and statutory framework

The State Highway Administration has statutory authority to determine the location, design, construction, and maintenance of the entire State highway system, a grant of authority Maryland courts have long read as vesting SHA with plenary, exclusive control, extending to State roads that happen to run through a municipality. Because SHA's own policy rejects speed bumps anywhere on roads it controls, and because a municipality cannot pass an ordinance contrary to state law or exercise control over roads under SHA's jurisdiction, the opinion found no room for a municipality to install speed bumps on a State highway.

For municipal streets, the analysis was different. The Maryland Vehicle Law is generally preemptive, meaning local governments cannot make their own rules on any subject the Vehicle Law already covers, but local authorities retain specific carved-out powers, including regulating traffic through police officers or "traffic control devices" that conform to state specifications. The opinion worked through the statutory definition of "traffic control device," a sign, signal, marking, or device placed to regulate, warn, or guide traffic, and the state and national manuals implementing that definition, and found speed bumps did not fit: they are a physical pavement feature that slows vehicles directly rather than a device that communicates a rule or warning, and they are omitted entirely from both the state and federal uniform traffic control device manuals. Because speed bumps therefore are not a "subject covered by the Maryland Vehicle Law" at all, the Vehicle Law's preemption provisions simply do not reach them, leaving a municipality free to rely on its independent, broadly granted police power (the authority to preserve peace, order, and public safety) to decide whether a speed bump is warranted on a residential street it controls. The opinion then layered on ordinary municipal tort-liability principles: because Maryland law recognizes a municipality's duty to keep its own streets reasonably safe as a significant exception to governmental immunity, and requires warning of hazards that are "unusual and extraordinary in nature," a town installing a device that engineering literature had flagged as a hazard to cyclists, motorcyclists, and emergency vehicles needed to exercise real care in siting, designing, and marking any bump it installed.

Citations

Statutes:

• TR §8-204(c) and (i) (SHA's authority over the State highway system's location, design, and maintenance)
• TR §8-101(q) (definition of "State highway system")
• TR §8-101(p) (definition of "State highway")
• Article 23A, §2 (municipal ordinances may not contravene public general law; grant of municipal police power)
• Article 23B, §75 and §76 (model municipal charter provisions on public ways, excluding SHA-controlled roads)
• TR §25-101.1(a) (Vehicle Law's statewide preemptive effect)
• TR §25-101.1(b)(3) (bar on local ordinances covering Vehicle Law subjects)
• TR §25-101.1(c)(1) (Vehicle Law prevails over conflicting local ordinances)
• TR §25-102(a)(2) (local authority to regulate traffic via police officers or traffic control devices)
• TR §25-106 (local duty to place and maintain necessary traffic control devices)
• TR §11-130 (definition of "local authority")
• TR §25-104(a) (SHA's traffic control device manual and specifications)
• TR §11-167 (definition of "traffic control device")

Cases:

• Contino v. Baltimore & Annap. R. Co., 178 F.2d 521, 523 (4th Cir. 1949)
• State Roads Comm'n v. Postal Tel. Cable Co., 123 Md. 73, 76 (1914)
• National Asphalt Pavement Ass'n v. Prince George's County, 292 Md. 75, 80 (1981)
• Lee v. Leitch, 131 Md. 30 (1917)
• McRobie v. Mayor and Commissioners, 260 Md. 464, 466 (1971)
• Weisner v. Mayor and Council, 245 Md. 225, 228 (1967)
• Tadjer v. Montgomery County, 300 Md. 539, 548 (1984)
• Mayor and City Council v. Thompson, 171 Md. 460, 467 (1937)
• Gordon v. Howard County, 13 Md. App. 42, 48 (1971)

Source

• Landing page: https://oag.maryland.gov/resources-info/Pages/attorney-general%E2%80%99s-opinions.aspx
• Original PDF: https://oag.maryland.gov/resources-info/Documents/pdfs/Opinions/1986/Volume71_1986.pdf

Original opinion text

Best-effort transcription from a scanned PDF. Minor errors may remain, the linked PDF is authoritative.

Vehicle Laws—Municipalities—"Speed Bumps"—Municipalities Have Authority To Place Speed Bumps On Municipal Streets, But Not On State Highways—Risk Of Liability Requires Careful Attention To Location, Design, And Warning Signs.

April 2, 1986

The Honorable Dennis C. Donaldson
Maryland House Of Delegates

You have requested our opinion on the authority of a municipality to install speed bumps on a public thoroughfare in the municipality and on the municipality's risk of liability for damage to vehicles if it does so. A "speed bump," we understand you to mean, is a raised area of asphalt intended to force motorists to slow down in order to avoid a potentially damaging jolt.

For the reasons given below, we conclude as follows:

(1) A municipality has no authority to install speed bumps on State highways in the municipality.

(2) A municipality may exercise its police powers by installing speed bumps on its own streets and highways.

(3) Because of the risk of liability, a municipality that installs speed bumps must exercise caution in choosing the location and design of the bumps and in placing appropriate warnings.

I
Powers of the State and Municipalities

A. State Highway Administration Authority

The State Highway Administration ("SHA") "shall determine and may change from time to time the location, construction, geometrics, design, and maintenance of the State highway system." §8-204(c) of the Transportation Article ("TR" Article). Furthermore, SHA "shall plan, select, construct, improve, and maintain the State highway system." TR §8-204(i). The "State highway system" is defined as "the system of state-owned primary and secondary highways throughout this State" [TR §8-101(q)], and "State highway" is defined as "any public highway owned by this State" [TR §8-101(p)].

Under these provisions, SHA has jurisdiction over, and the right to improve and maintain, all public highways that are part of the State highway system. This jurisdiction extends to "any" State-owned highway, including those that pass through municipalities.

This grant of authority is plainly intended to vest in SHA sole decisionmaking authority concerning State highways. "[The predecessor of SHA] was created in 1908 and by statutes then and subsequently passed it was granted plenary power to select, construct, improve and maintain a system of improved highways for the state within the limits of the funds provided therefor." Contino v. Baltimore & Annap. R. Co., 178 F.2d 521, 523 (4th Cir. 1949) (emphasis added). See also State Roads Comm'n v. Postal Tel. Cable Co., 123 Md. 73, 76 (1914) (predecessor of SHA "vested with powers of control and regulation over the public highways").

Thus, as to State highways, a municipality does not have authority to install speed bumps without SHA's approval, because SHA retains overall responsibility for maintenance and improvement. See Article 23A, §2 (municipality may not pass ordinances "contrary to ... public general law"). See also Article 23B, §75 (model municipal corporation charter excludes from town control public ways "that are under the jurisdiction of [SHA]").

As a matter of policy, SHA does not install speed bumps on any of the highways under its control, based on its assessment of the potential hazards of speed bumps even in the best design situations. See, e.g., Department of Transportation, Federal Highway Administration, State of the Art Report: Residential Traffic Management, Report No. FHWA/RD-80/092, at 25 (1980) ("There are several reasons [why the use of speed bumps] on public streets has been limited. The major one is a real and perceived question as to their safety."). Hence, speed bumps may not be installed on any State highway, regardless of its location.

B. Municipal Authority

1. Introduction

The Maryland Vehicle Law, Titles 11 through 27 of the Transportation Article, generally covers the registration and titling of vehicles; the licensing of dealers; the licensing of drivers; rules of the road; and restrictions on the size, weight, and permissible loads of various vehicles. TR §25-101.1(a) describes the Vehicle Law's preemptive scope: "Except as otherwise expressly provided, the provisions of the Maryland Vehicle Law are statewide in their effect." Local authorities and political subdivisions are prohibited from "mak[ing] or enforc[ing] any local law, ordinance, or regulation on any subject covered by the Maryland Vehicle Law." TR §25-101.1(b)(3). Furthermore, its provisions prevail over all local ordinances and regulations on "any subject covered by the Maryland Vehicle Law." TR §25-101.1(c)(1). See generally 10 McQuillan, Municipal Corporations §30.40 at 685-86 (3d ed. 1981) ("Municipal control and regulation of streets must harmonize with the laws and policy of the state. This is so because all public highways are under the paramount control of the state, and municipal powers related thereto are mere delegations of state authority.").

2. Exception to preemption, "traffic control devices"

The preemption of the Maryland Vehicle Law over municipal ordinances is not complete, however. Local authorities, including municipalities, do retain certain specified powers over highways under their jurisdiction, including the "regulating [of] traffic by means of police officers or traffic control devices." TR §25-102(a)(2). A local authority is "a political subdivision or a local board or other body that, under the laws of this State, has authority to enact laws and adopt local police regulations relating to traffic." TR §11-130. Under TR §25-102(a), a local authority may, among other things: (2) Regulate traffic by means of police officers or traffic control devices; (10) Alter speed limits as provided in Title 21, Subtitle 8 of the Vehicle Law; and (12) Adopt any other traffic regulations as specifically authorized in the Maryland Vehicle Law.

In addition, pursuant to TR §25-106, a local authority is required "to place and maintain" on highways under its jurisdiction "those traffic control devices that it considers necessary to carry out the provisions of the Maryland Vehicle Law or local traffic ordinances or to regulate, warn, or guide traffic." However, these traffic control devices must "conform to the manual and specifications" of SHA, which in turn is to adopt "a manual and specifications for a uniform system of traffic control devices." TR §25-104(a). Accordingly, if speed bumps are a "traffic control device" under SHA's manual and specifications, then a municipality would be authorized to place speed bumps on public thoroughfares.

The term "traffic control device" is defined in TR §11-167 as follows:

"'Traffic control device' means any sign, signal, marking, or device that:

(1) Is not inconsistent with the Maryland Vehicle Law; and

(2) Is placed by authority of an authorized public body or official to regulate, warn, or guide traffic."

At first glance, a speed bump would appear to fall within this definition. However, traffic control devices installed by municipalities must conform to SHA's manual and specifications, and that manual is to conform, as far as possible, to the most recent edition of the Manual on Uniform Traffic Control Devices for Streets and Highways ("Uniform Manual"). TR §25-104(a). The Uniform Manual, which is published by the Federal Highway Administration, includes specifications for signs, signals, markings, and traffic islands, but makes no mention of speed bumps. SHA's manual adopts the Uniform Manual in toto, and similarly does not include speed bumps. In fact, manuals on traffic control devices throughout the country exclude speed bumps. "[Speed bumps] are not included in the Manual of Uniform Traffic Control Devices and parallel state traffic control and design guides." Federal Highway Administration, State of the Art Report: Residential Traffic Management at 25.

Furthermore, in contrast to the definition of "traffic control device," a speed bump is not intended to "regulate, warn, or guide traffic," as a sign, signal, or marking would. Rather, in engineering terms, a speed bump is a pavement design feature intended to reduce speed on a street or highway. SHA administratively has never considered speed bumps to be traffic control devices, and that kind of consistent construction by the agency responsible for administering a statute is entitled to considerable weight. E.g., National Asphalt Pavement Ass'n v. Prince George's County, 292 Md. 75, 80 (1981).

For these reasons, speed bumps do not fall within the definition of "traffic control devices" in TR §11-167.

3. Residual police power

Because speed bumps are not traffic control devices, there is no specific authorization under TR §§25-102 or 25-106 for municipalities to place speed bumps on public streets under their jurisdiction. Indeed, we conclude that the matter of speed bumps is altogether beyond the purview of the Vehicle Law. It is simply not a "subject covered by the Maryland Vehicle Law." TR §25-101.1(b)(3). Therefore, while the Vehicle Law does not itself authorize speed bumps on municipal streets, it does not preempt whatever authority a municipality otherwise has to place speed bumps.

A municipality generally has the power to control and supervise its streets and highways. This power is part of the grant of police power to municipalities. See Lee v. Leitch, 131 Md. 30 (1917). Broad police powers have been expressly granted to incorporated municipalities by Article 23A, §2 of the Maryland Code. A municipal corporation can exercise powers "'granted in express words'"; "'necessarily or fairly implied in or incident to'" the express powers; or "'essential to the accomplishment of the declared objects and purposes'" of the municipality. McRobie v. Mayor and Commissioners, 260 Md. 464, 466 (1971) (quoting 1 Dillon, Municipal Corporations §237 (5th ed.)) (emphasis omitted).

These powers include the power "to preserve peace and good order [and] to secure persons and property from danger and destruction." Article 23A, §2. In our view, a municipality would be acting well within this grant of authority if it determined that a speed bump were necessary to achieve this objective on a public thoroughfare under its jurisdiction, that is, to protect the residents of a residential street against the danger of speeding vehicles. See also Article 23B, §§75 and 76 (model municipal corporation charter provisions concerning municipal public ways).

II
Municipality's Risk of Liability

Under Maryland law, a municipal corporation owes a duty to persons lawfully using the public streets under its control to make those streets "reasonably safe for passage." Weisner v. Mayor and Council, 245 Md. 225, 228 (1967). See generally 10 McQuillan, Municipal Corporations §30.41 at 695 ("It is elementary that it is the duty of municipalities to exercise ordinary care to keep and maintain its streets, sidewalks and alleys in repair and safe for public use."). However, this is not an absolute duty; the municipality is not an insurer of safe passage.

A municipality's "duty to maintain streets and highways in a reasonably safe condition is a major exception to the immunity from suit" otherwise enjoyed by Maryland counties and municipalities. Tadjer v. Montgomery County, 300 Md. 539, 548 (1984). As stated by the Court of Appeals:

"[A municipality] may ... be liable for injuries caused by an obstruction in a public highway of which it had sufficient notice, even though the obstruction is authorized by proper municipal and legislative authority, where it is reasonably foreseeable that it will endanger persons using the highway while in the exercise of reasonable care, unless it takes the precaution of warning such persons of the danger by some reasonably adequate means." Mayor and City Council v. Thompson, 171 Md. 460, 467 (1937).

The legal duty to post warning signs or take other precautionary methods to guard the safety of the travelling public arises if the hazardous condition is "unusual and extraordinary in nature." Gordon v. Howard County, 13 Md. App. 42, 48 (1971).

In light of these principles of law, we are of the opinion that a municipality could be exposing itself to possible liability for failing to keep its streets safe and failing to warn the public of hazardous conditions if it were to construct speed bumps without special consideration as to their construction and location and without providing proper signs warning of upcoming bumps. While intended as a safety measure to reduce the speed of vehicles, speed bumps can be a hazard of a kind that is not ordinarily expected on a public thoroughfare. There are no Maryland cases regarding the liability issues raised by speed bumps, but one engineering study has flatly concluded that "[they] present an immediate and specific hazard to some vehicles, (the bicycle, the motorcycles, and the fire truck) and a potential hazard to all vehicles." City of San Jose, California, A Study of Speed Bumps (1975). The study also concluded that speed bumps are not effective in reducing vehicle speeds.

Therefore, we caution any municipality considering the installation of speed bumps to be aware of the potential risks involved. Speed bumps should be installed only after careful engineering study and should be used only where the potential safety hazard from their use is low, on lightly travelled, low speed thoroughfares, such as those in residential neighborhoods.

III
Conclusion

In summary, it is our opinion that:

(1) A municipality has no authority to install speed bumps on State highways in the municipality.

(2) A municipality may exercise its police powers by installing speed bumps on its own streets and highways.

(3) Because of the risk of liability, a municipality that installs speed bumps must exercise caution in choosing the location and design of the bumps and in placing appropriate warnings.

Stephen H. Sachs
Attorney General
Thomas G. Peter
Assistant Attorney General

Jack Schwartz
Chief Counsel
Opinions and Advice