1. New Hampshire DWI Laws
In New Hampshire, there are a few types of charges related to Driving While Intoxicated (DWI). Driving Under the Influence (DUI), and Driving While Intoxicated (DWI), are synonyms, and are used interchangeably in the statute.
1.2 Driving Under the Influence of Alcohol (Ability Impaired)
The most common DWI charge is driving while under the influence of alcohol. The statute makes it unlawful to: drive or attempt to drive a vehicle upon any way or operate or attempt to operate an OHRV: (a) While such person is under the influence of intoxicating liquor.
To be convicted of this offense, the State must prove three things beyond a reasonable doubt:
1: Driving or Operation,
2: on a public way,
3: under the influence of alcohol (ability impaired to any degree due to alcohol).
Public Way, as it relates to the DWI statute means: any public highway, street, avenue, road, alley, park, parking lot or parkway; any private way laid out under authority of statute; ways provided and maintained by public institutions to which state funds are appropriated for public use; any privately owned and maintained way open for public use; and any private parking lots, including parking lots and other out-of-door areas of commercial establishments which are generally maintained for the benefit of the public.
Practice Note: According to District Court Rule 1.22, you must specifically demand at least 10 days prior to trial notice to have the State prove public way, or else it is deemed waived.
1.3 Driving while having a Blood Alcohol Content above the Legal Limit (Per Se Offense)
The second most common type of DWI is driving while having an alcohol concentration above the legal limit. This limit is .08, or .02 for drivers under 21. If charged with a per se offense, the driver will almost always also be charged with driving while their ability is impaired (Except underage drivers, the State might not bring the ability impaired offense, particularly with a low BAC). To obtain a conviction, the State must prove three things beyond a reasonable doubt:
1: Driving or Operation
2: on a public way
3: while such person has an alcohol concentration of 0.08 or more (Or in the case of a person under the age of 21, 0.02 or more).
1.4 Driving while Ability Impaired due to a Controlled Drug (DWI Drugs)
To obtain a conviction for DWI Drugs, the State must prove three things beyond a reasonable doubt:
1: Driving or Operation
2: On a public way
3: under the influence of a controlled drug (ability can be impaired to any degree due to a controlled drug).
Practice Note: The State must prove a Controlled Drug. Many drugs are not controlled drugs.
Further, there is no equivalent per se drug statute. This means that, no matter what quantity of drugs may be in a person’s system, the State must still prove the drugs impaired the person’s ability to drive. Finally, there is no presumption that a certain quantity of a controlled drug leads to impairment.
1.5 Aggravated DWI
If a driver commits the crime of DWI, there are five additional things that can make the crime an Aggravated DWI.
1: Drives or operates at a speed more than 30 miles per hour in excess of the prima facie limit;
2: Causes a motor vehicle, boating, or OHRV collision resulting in serious bodily injury, as defined in RSA 625:11, VI, to the person or another;
3: Attempts to elude pursuit by a law enforcement officer by increasing speed, extinguishing headlamps or, in the case of a boat, navigational lamps while still in motion, or abandoning a vehicle, boat, or OHRV while being pursued; or
4: Carries as a passenger a person under the age of 16;
5: While having an alcohol concentration of 0.16 or more.
Again, besides proving the underlying DWI, the State must prove any of these aggravating factors beyond a reasonable doubt to obtain a conviction for Aggravated DWI.
1.6 Boating while Intoxicated (BWI)
No person shall operate or attempt to operate a boat while under the influence of intoxicating liquor or a controlled drug or any combination of intoxicating liquor and a controlled drug or drugs, or while such person has an alcohol concentration of 0.08 or more (Or in the case of persons under the age of 21, 0.02 or more.)
This crime is identical to the DWI ability impaired and per se offense, except that instead of proving operating a vehicle on a way, the State must prove operating a boat.
''Boat'' means and includes every type of watercraft used or capable of being used as a means of transportation on the water.
"Operate,'' when used in relation to a boat, means to drive, paddle, row, or exercise control over any boat unless the boat is at anchor, docked, made fast, or moored.
1.7 DWI Subsequent Offense
In order to obtain a conviction for DWI subsequent offense, the State must first prove the underlying DWI, and then the State must also prove beyond a reasonable doubt a previous conviction for DWI.
Additionally, for a second offense DWI charge, the previous conviction must have been within the previous 10 years.
1.8 Felony DWI
It is worth noting, that there are only two types of Felony DWI charges, all the others are either Class A or Class B misdemeanors.
N.H. RSA 265-A: Alcohol and drug impairment
 N.H. RSA 265-A:2(I)(a)
State v. Taylor, 132 N.H. 314, 316 (1989Error! Bookmark not defined.)
 N.H. RSA 259:125
 N.H. RSA 265-A:2(I)(b)
 "Alcohol concentration'' shall mean either grams of alcohol per 100 milliliters of blood, grams of alcohol per 67 milliliters of urine, or grams of alcohol per 210 liters of breath. - N.H. RSA 259-B:3
 The Motor Vehicle Chapter (N.H. RSA 259:13-b ) defines Controlled Substance as: “any substance so classified under section 102(6) of the Controlled Substances Act (21 USC section 802(6)), and includes all substances listed on schedules I through V of 21 CFR 1308, as they may be revised from time to time, or any controlled drug as defined in RSA 318-B:1, VI.” There is an argument to be made that because the DWI Statute references “controlled drug”, that the more narrow definition applies.
 N.H. RSA 265-A:3
 N.H. RSA 265-A:2(II)
 N.H. RSA 265-A:1(II)
 N.H. RSA 265-A:1(V)
State v. Lougee, 137 NH 635, 636 (1993)
 N.H. RSA 265-A:18(IV)
 N.H. RSA 265-A:18(IV)(c)
 N.H. RSA 265-A:18(I)(c)