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DUI Laws

Citizens Count Editor

In New Hampshire it is illegal to drive a car or operate any other vehicle while under the influence of drugs or alcohol. 

See New Hampshire’s law on operating under the influence of drugs or alcohol

Sobriety test rules

Law enforcement may ask anyone operating a vehicle in New Hampshire to take various tests to determine if he or she is operating under the influence, such as a breath test or a blood test. 

If a person refuses to take a test, he or she faces automatic license suspension for 180 days. Even if someone refuses a test, law enforcement can gather other evidence that suggests the driver was intoxicated (such as open alcohol containers in the car), and a person may still be charged with operating under the influence.

Blood alcohol limits

While it can be difficult to judge if a person is intoxicated by marijuana or another drug, the law spells out specific thresholds for alcohol. 

  • It is illegal for anyone over the age of twenty-one to operate a vehicle with a blood alcohol concentration (BAC) of 0.08 or more in New Hampshire. 
  • Commercial drivers have a BAC limit of 0.04. 
  • For anyone under age twenty-one, the BAC limit is 0.02. 

The number of drinks it takes to reach a 0.08 BAC varies greatly depending on a number of factors, including weight, age, gender, the time period over which the drinks were consumed, and how much you’ve had to eat.

You can use an online BAC calculator to estimate your blood alcohol level, but note that this isn't necessarily accurate since everyone processes alcohol differently. The only safe way to be sure your blood alcohol level is below the legal limit is not to drink before you drive.

Marijuana and other drugs

Blood tests may determine if a driver if intoxicated by a drug other than alcohol, but those tests are problematic. For example, there is currently no test for marijuana intoxication that is 100% reliable.  Marijuana affects people differently, and THC — the psychoactive drug in marijuana — can stay in a person’s body for days or even weeks. This can make it difficult for prosecutors to prove an individual was operating under the influence of a drug other than alcohol.

However, if a driver is found transporting any controlled drug, his or her license will be suspended for at least sixty days, whether or not he or she is intoxicated.

Penalties for drunk and drugged driving

Driving under the influence in New Hampshire means a minimum sentence of:

  • License suspension of at least three months (at least one year if the offender is under age twenty-one) 
  • A fine of at least $500
  • An impaired driver education program
  • Screening for substance abuse disorder and, if necessary, completion of a treatment plan

Penalties get stronger for repeat or serious offenders or for people who violate the terms of their first sentence, and can include:

  • Jail time
  • Installation of an ignition interlock device (which requires the driver to pass a breath test to start a car)
  • Longer license suspensions
  • Random drug testing

A person may apply to annul a DUI conviction after ten years.  If it is a person’s first DUI conviction, he or she may petition the court to reduce the conviction to a violation after one year.

Learn more about criminal records annulment

Cinderella license law

The first time someone is convicted of driving under the influence in New Hampshire, he or she may petition the court for limited driving privileges, sometimes called a “Cinderella license,” after forty-five days of license suspension. 

A Cinderella license allows the person to drive to work, job training, education, addiction treatment, or other necessary medical treatment.  The driver must install an ignition interlock device.

Sobriety checkpoints

A sobriety checkpoint is a police roadblock that systematically checks passing drivers for signs of intoxication. 

While some state courts have ruled sobriety checkpoints violate the constitutional protection against unreasonable search and seizure, the U.S. Supreme Court ruled sobriety checkpoints are legal.

In New Hampshire, police have to get permission from a court to hold sobriety checks, which are then advertised in the newspaper.

Laws in other states

Some states have stricter DUI laws.  Here are some examples:

  • Lower BAC limits: for example, Utah will lower the BAC limit for drunk driving to 0.05 starting in 2019.
  • Visible identifiers: drivers found operating under the influence in Ohio can be required to use special red and yellow license plates.
  • Insurance penalties: about half of states have a law that allows insurance companies to deny a claim for an injury that occurred while a person was intoxicated. 
  • Health provider reporting requirements: some states, such as Oregon, require health care professionals to contact law enforcement if a patient from a car accident has a BAC over the legal limit.
  • Mandatory impounding: some states, such as Mississippi, allow or require courts to impound a vehicle after the owner is arrested or convicted of driving under the influence. The impoundment can last anywhere from a few hours to a few months, depending on the state.
  • Strict THC rules: some states, such as Delaware, have a zero tolerance law that makes it a crime to drive with any trace of THC (the psychoactive drug in marijuana) in the blood.

Learn more about other issues related to road safety

Citizens Count Editor

“NH should impose stronger penalties for DUI.”

  • A 2017 report from WalletHub ranked New Hampshire 31st in the nation for the strictness of its drunk driving penalties. This ranking shows New Hampshire has room to grow compared to other states when it comes to DUI laws.  For example, other states impose longer jail sentences, allow judges to impound a drunk driver’s vehicle, or make operating under the influence an automatic felony after just one conviction. 
  • According to data from the National Highway Traffic Safety Administration, the percentage of fatal traffic collisions involving a drunk driver in New Hampshire has not decreased significantly over the past twenty years, staying near 30%. This shows New Hampshire needs to do more to decrease drunk driving.
  • Law enforcement in New Hampshire have expressed concern that marijuana decriminalization in New Hampshire—and legalization in neighboring states—will increase the number of people driving while impaired by marijuana.  To discourage residents from driving while high, New Hampshire needs stricter penalties for driving with any amount of THC (the psychoactive drug in marijuana) in the blood.  Current law is too ambiguous about what qualifies as operating under the influence of marijuana.
Citizens Count Editor

“NH should not impose stronger penalties for DUI.”

  • According to the Centers for Disease Control and Prevention and the Insurance Institute for Highway Safety, the rates of drunk driving and drunk driving fatalities are lower in New Hampshire than the rest of the United States. These statistics suggest New Hampshire is doing an adequate job compared to other states in preventing drunk driving.
  • According to data from the Youth Risk Behavior Survey, from 2005 to 2015 the percentage of New Hampshire high schoolers who rode in the car with a drunk driver decreased from 22% to 16%. This shows that the number of young drivers operating under the influence in New Hampshire is decreasing.
  • According to the National Highway Traffic Safety Administration, more traffic fatalities in New Hampshire involve a person not wearing a seat belt than involve a drunk driver.  This suggests drunk driving is not the most pressing road safety issue in New Hampshire. 
  • When it comes to preventing impaired driving, public education campaigns are arguably just as effective and less expensive than harsh criminal penalties.


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