Did Maryland prosecutors have to prove a driver was actually driving unsafely to convict them of DUI, or was proof of intoxication itself enough?

Plain-English summary

A State's Attorney asked the Attorney General whether the State had to prove that a driver was operating a vehicle unsafely, and that the unsafe operation was caused by alcohol, in order to convict someone of driving while intoxicated or driving while under the influence of alcohol, since at least one District Court judge had read the statute that way. The opinion concluded that unsafe operation was not a required element of either alcohol offense under Tr §21-902(a) and (b). It reasoned that the Maryland Vehicle Law's separate drug-related offense, §21-902(c)(1), expressly required proof that the driver "cannot drive a vehicle safely," a restrictive clause the opinion found, as a matter of grammar, confined to that subsection alone and absent from the two alcohol-based subsections. Because the alcohol offenses instead came with their own statutory measurements, namely, the prima facie evidence thresholds for blood alcohol content in CJ §10-307(d) and (e), the opinion concluded the General Assembly deliberately chose not to impose the same unsafe-operation requirement for alcohol offenses that it imposed for drug offenses, a difference the opinion attributed to alcohol's more uniformly predictable, scientifically measurable effects on driving compared to the widely varying effects of different drugs.

Currency note

This opinion was issued in 1983. 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.

The opinion interpreted Tr §21-902 as it existed after a 1981 amendment and traced its legislative history back to 1969 and 1970 enactments. Maryland's DUI and driving-under-the-influence statutes, and the required elements of proof for each, have likely been revised since 1983; verify the current version of Tr §21-902 and current case law before relying on any specific description of what the State must prove.

Common questions

Did Maryland prosecutors have to show that a drunk driver was actually swerving, speeding, or driving dangerously to get a conviction?
No, according to this opinion. It concluded that proof of unsafe vehicle operation was not a required element of driving while intoxicated or driving while under the influence of alcohol, unlike the separate offense of driving under the influence of drugs, which did require proof the driver "cannot drive a vehicle safely."

Why did drug-related driving offenses require proof of unsafe driving when alcohol-related offenses didn't?
The opinion explained that alcohol has fairly uniform, scientifically measurable effects on driving ability that a blood alcohol test can reliably capture, while drugs vary widely in type and effect, making a chemical test alone insufficient, so the legislature required behavioral proof of actual unsafe driving only for the drug-based offense.

Did the State have to prove that a driver's alcohol consumption actually caused any unsafe driving?
No. The opinion concluded that because the State was not required to prove unsafe operation at all under §21-902(a) or (b), it followed that the State also did not need to prove any causal link between the driver's alcohol consumption and unsafe driving.

Background and statutory framework

The opinion analyzed Tr §21-902, which set out driving while intoxicated in subsection (a), driving under the influence of alcohol in subsection (b), and driving under the influence of drugs, or a combination of drugs and alcohol, "to a degree that he cannot drive a vehicle safely" in subsection (c)(1). Applying the statutory construction canon from Sullivan v. Dixon that a qualifying clause ordinarily modifies only the immediately preceding words, the opinion found the "cannot drive a vehicle safely" clause confined to subsection (c)(1) alone, with its absence from subsections (a) and (b) reflecting the General Assembly's deliberate choice not to require that proof for the alcohol offenses, following the interpretive principle recognized in American Security and Trust Co. v. New Amsterdam Casualty Co. that omission of a requirement from parallel statutory language implies its rejection.

The opinion supported this reading by pointing to the alcohol offenses' own built-in measurement standards, the blood-alcohol prima facie evidence thresholds in CJ §10-307(d) (0.08% for under the influence) and (e) (0.13% for intoxication), which it read as the General Assembly's chosen substitute for a behavioral unsafe-driving requirement. Tracing the statute's legislative history from a 1969 enactment splitting a single impaired-driving offense into separate alcohol and drug provisions, through a 1970 amendment creating the modern drug-offense structure, and a 1981 amendment removing a lingering "driving ability" reference from the alcohol-under-the-influence offense, the opinion found the legislative trend consistently moved toward decoupling the alcohol offenses from any unsafe-operation requirement while retaining that requirement only for drugs, whose effects vary too widely for a single chemical threshold to capture. The opinion clarified, citing Brooks v. State, that this conclusion did not make chemical test evidence mandatory or behavioral evidence inadmissible, only that neither was legally required to establish the offense.

Citations

Statutes:

• Tr §21-902(a) (driving while intoxicated)
• Tr §21-902(b) (driving while under the influence of alcohol)
• Tr §21-902(c)(1) (driving under the influence of drugs or drugs and alcohol to a degree rendering unsafe driving)
• CJ §10-307(d) (0.08% blood alcohol prima facie evidence of under the influence)
• CJ §10-307(e) (0.13% blood alcohol prima facie evidence of intoxication)
• Chapter 158, Laws of Maryland 1969 (original split into alcohol and drug offenses)
• Chapter 534, Laws of Maryland 1970 (creation of modern drug-offense structure)
• Former Article 66½, §206 (pre-1969 combined impaired-driving offense)
• Former Article 66½, §11-902 (predecessor to current §21-902)

Cases:

• Sullivan v. Dixon, 280 Md. 444, 451 (1977)
• American Security and Trust Co. v. New Amsterdam Casualty Co., 246 Md. 36, 41 (1967)
• Brooks v. State, 41 Md. App. 123, 128 (1979)

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/1983/Volume68_1983.pdf

Original opinion text

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

Vehicle Laws—Alcohol-Related Offenses—Evidence Required—Proof of Unsafe Vehicle Operation not a Necessary Element of Driving While Intoxicated or Under the Influence of Alcohol.

May 2, 1983

The Honorable Walter B. Dorsey
State's Attorney for St. Mary's County

You have requested our opinion on the scope of the evidence required to sustain a conviction for the offenses of driving while intoxicated or driving while under the influence of alcohol. Specifically, you ask whether the State, in order to obtain a conviction under the applicable provisions of the Maryland Vehicle Law, must establish that the driver was operating a vehicle unsafely and that such unsafe operation was caused by the driver's consumption of alcohol.1

For the reasons given below, it is our opinion that proof of unsafe operation is not a necessary element of the offenses of driving while intoxicated or driving while under the influence of alcohol.

1 You indicate that at least one District Court Judge has construed the statute to require that the State bear this burden of proof.

I
The Statute

The Maryland Vehicle Law, in §21-902 of the Transportation Article, specifies a number of offenses involving impaired driving. Section 21-902(a) provides that: "A person may not drive or attempt to drive any vehicle while intoxicated." Section 21-902(b), in turn, provides that: "A person may not drive or attempt to drive any vehicle while under the influence of alcohol." Finally, Section 21-902(c)(1) provides that: "A person may not drive or attempt to drive any vehicle while he is so far under the influence of any drug, any combination of drugs, or a combination of one or more drugs and alcohol that he cannot drive a vehicle safely."2

2 The remaining provisions in §21-902 are not pertinent to the analysis of your question.

II
Analysis

As your inquiry notes, proof of unsafe operation is undoubtedly a necessary element of the State's case in a prosecution for a violation of §21-902(c)(1), driving under the influence of drugs or a combination of drugs and alcohol. In our view, however, the presence in §21-902(c)(1) of the restrictive clause "that he cannot drive a vehicle safely", and the absence of that or a similar clause from §21-902(a) and (b), establish that the General Assembly did not intend to require proof of unsafe operation in a prosecution under §21-902(a) or (b).

As a matter of both grammar and statutory construction, the restrictive clause modifies only the immediately preceding provisions of §21-902(c)(1): "while he is so far under the influence of any drug, any combination of drugs, or a combination of one or more drugs and alcohol". See Sullivan v. Dixon, 280 Md. 444, 451 (1977) ("the generally recognized rule of statutory construction [is] that a qualifying clause ordinarily is confined to the immediately preceding words or phrase").3 Thus, proof "that [the driver] cannot drive a vehicle safely" is a statutorily required measurement of the degree of drug (or drug and alcohol) influence.

3 In Sullivan v. Dixon, the qualifying clause was held to modify only the last in a series of nouns within the same sentence. Surely the qualifying clause "that he cannot drive a vehicle safely" in §21-902(c)(1) cannot possibly modify language in entirely different subsections.

By contrast, neither §21-902(a) nor §21-902(b) contains that qualifying clause. Rather, the only specified measurements of intoxication and of driving under the influence of alcohol are those found in §10-307(d) and (e) of the Courts Article: "(d) Prima facie evidence of impairment.—If at the time of testing there was in the person's blood 0.08 percent or more by weight of alcohol, as determined by an analysis of the person's blood or breath, it shall be prima facie evidence that the defendant was driving under the influence of alcohol. (e) Prima facie evidence of intoxication.—If at the time of testing there was in the person's blood 0.13 percent or more by weight of alcohol, as determined by an analysis of the person's blood or breath, it shall be prima facie evidence that the defendant was intoxicated."

In our view, having provided that intoxication and driving under the influence of alcohol may be measured by these forms of evidence, the General Assembly should not be understood to have imposed an unstated, additional evidentiary requirement such as proof of unsafe operation. To the contrary, under the principles of statutory construction reiterated by the Court of Appeals, the absence of the additional requirement from §21-902(a) and (b) implies its deliberate rejection. See, e.g., American Security and Trust Co. v. New Amsterdam Casualty Co., 246 Md. 36, 41 (1967).

Here, the statutory language plainly conveys the elements, all of the elements, of each alcohol-related offense: (i) proof that the defendant drove or attempted to drive the vehicle; and (ii) proof that the defendant was, at the time, intoxicated [§21-902(a)] or under the influence of alcohol [§21-902(b)].4

4 Given the clarity of the statutory language, recourse to legislative history is unnecessary. In any event, the legislative history supports our construction of §21-902. Formerly, then Article 66½, §206 declared it unlawful for "any person who is under the influence of intoxicating liquor or narcotic drugs to drive or attempt to drive any vehicle". In 1969, this provision was amended to state two separate offenses: (a) driving while "in an intoxicated condition, or under the influence of narcotic drugs"; and (b) driving while one's "driving ability is impaired by the consumption of alcohol". Chapter 158, Laws of Maryland 1969. In 1970, the General Assembly deleted the reference to "narcotic drugs" in subsection (a) of then Article 66½, §11-902. In its stead, the predecessor of current subsection (c)(1) was enacted: "It shall be unlawful for any person to drive . . . while he is under the influence of any narcotic drug or while under the influence of any other drug to a degree which renders him incapable of safely driving a vehicle." Chapter 534, Laws of Maryland 1970. Thus, by 1970 the General Assembly had adopted essentially the current statutory scheme: two alcohol-related offenses, neither of which required proof of unsafe operation; and a drug-related offense, which (as to non-narcotic drugs) did not require proof of unsafe operation. Although the lesser of the two alcohol-related offenses retained a vague reference to "driving ability", "while [the defendant's] driving ability is impaired by the consumption of alcohol", even this reference was removed in 1981 when the General Assembly changed §21-902(b) to its current language: "A person may not drive . . . while under the influence of alcohol."

The different element of proof for the drug-related offense set out in §21-902(c)(1) presumably reflects a significant difference between alcohol and drugs. All forms of alcohol have similar, harmful effects on coordination and other driving skills, and these harmful effects can be accurately inferred from a blood alcohol test. Behavioral evidence, such as evidence of unsafe operation, is therefore unnecessary to the proof of the offenses under §21-902(a) or (b).5 By contrast, the wide variety of drugs and their widely varying effects mean that a scientific measure like blood alcohol testing is not feasible. Only behavioral evidence, proof that the driver "cannot drive a vehicle safely", can establish the harmful effects of a given drug.

5 We do not mean to imply that the results of a blood alcohol test are always needed to sustain a conviction under §21-902(a) or (b) or that evidence of a driver's behavior is inadmissible in such a prosecution. See generally Brooks v. State, 41 Md. App. 123, 128 (1979) (Chemical evidence "is probative, but it is unnecessary for conviction. Other evidence, particularly the personal observations by a witness of the individual's behavior may be sufficient.")

III
Conclusion

In summary, it is our opinion that a showing of the unsafe operation of a motor vehicle is not a necessary element of proof in a prosecution under §21-902(a) or (b) of the Transportation Article of the Maryland Code.6

Stephen H. Sachs, Attorney General
Jack Schwartz, Assistant Counsel,
Opinions and Advice
Avery Aisenstark
Chief Counsel
Opinions and Advice

6 Just as the State need not prove that the vehicle was driven unsafely to sustain a conviction under §21-902(a) or (b), it follows that the State need not prove any causative link between alcohol consumption and unsafe driving.