New Hampshire DWI & DUI Laws
BAC limits, penalties, license suspension periods, and ignition interlock requirements for New Hampshire drivers.
State Guide
New Hampshire DWI Laws at a Glance
Impaired driving is prosecuted under DWI in New Hampshire, with a 0.08% BAC threshold. The penalty structure that follows a conviction (license suspension, interlock requirements, how prior offenses are counted) is entirely state-specific.
| Detail | New Hampshire Rule | Notes |
|---|---|---|
| Statutory Term | DWI | The specific offense name and code section vary by state |
| Standard BAC Limit | 0.08% | The standard threshold used in nearly every state |
| First-Offense License Suspension | 9 months | Administrative and criminal suspensions can run separately; actual length depends on case specifics |
| Ignition Interlock Device | Conditional | Required for high-bac or repeat offenders, but not automatically for a standard first offense |
| Lookback Period | Not consistently published | Confirm the current lookback window against state code. This figure is not consistently published across states |
How BAC Testing and Implied Consent Work
Like every state, New Hampshire relies on implied consent: operating a vehicle on public roads means you've consented to BAC testing if lawfully arrested for suspected impairment. Refusing that test comes with its own separate consequence, usually an automatic license suspension, regardless of how the DWI charge itself is resolved.
License Suspension: Two Separate Tracks
A DWI arrest in New Hampshire can trigger two separate tracks, an administrative suspension through the motor vehicle agency that moves quickly and independently of the courtroom process, and the criminal case itself. For a first offense, New Hampshire's suspension period is 9 months.
Common Questions
Frequently Asked Questions: DWI in New Hampshire
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What is the BAC limit in New Hampshire?New Hampshire's standard illegal BAC threshold is 0.08%. This matches the standard used in nearly every U.S. state. Commercial drivers and drivers under 21 face lower thresholds in every state, including New Hampshire.
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How long is a license suspended for a first DWI offense in New Hampshire?New Hampshire's first-offense suspension period is generally 9 months. This can involve both an administrative suspension (handled by the state's motor vehicle agency, often starting soon after arrest) and consequences tied to the criminal case itself, which can run on a different timeline.
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Does New Hampshire require an ignition interlock device?In New Hampshire, an ignition interlock device is required for high-BAC or repeat offenders, but not automatically for a standard first offense. Requirements can also depend on whether a high BAC was involved or whether it's a repeat offense.
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What does "DWI" mean in New Hampshire?DWI is New Hampshire's statutory term for operating a vehicle while impaired by alcohol or drugs above the legal threshold. Different states use different terms (DUI, DWI, OWI, OUI, OVI, and others) for what is fundamentally the same category of offense, though the exact legal definitions and penalty structures differ by state.
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What happens if I refuse a BAC test in New Hampshire?Like every state, New Hampshire has an implied consent law: refusing a lawfully requested BAC test after a DWI arrest triggers its own penalty, typically an automatic license suspension, separate from and in addition to any penalty from the underlying charge itself.
Sources & References
- National Highway Traffic Safety Administration, Drunk Driving official program overview
- Insurance Institute for Highway Safety, Alcohol Interlock Laws by State
- New Hampshire BAC limit, suspension period, and interlock requirement figures compiled from published state-by-state legal reference tables; confirm current figures against official NH state code before relying on them
- Governors Highway Safety Association, Alcohol-Impaired Driving State Laws