New Hampshire has decriminalized (but still restricts) the possession and use of marijuana. But driving while under the influence of marijuana or any other drug is still very much illegal. This article explains how certain substances can lead to an impaired driving conviction as well as the associated penalties.
New Hampshire prohibits driving while intoxicated (DWI) by any drug or other impairing substance. A driver is considered under the influence if he or she is impaired to any degree. In other words, you don't have to be completely out of it to get a DWI—even slight impairment is enough.
Proof of impairment. New Hampshire prohibits impaired driving but does not have a per se limit for drug metabolites (similar to the .08% alcohol limit). To get a conviction, the state will generally need to prove the driver consumed some substance and was impaired by that substance. Proof of impairment might include blood test results, expert testimony, and the observations of the arresting officers.
Intoxicating substances that can lead to a DWI. A New Hampshire DWI can be based on impairment from the use of controlled drugs, prescription drugs, over-the-counter drugs, or any other chemical substance which impairs a person's ability to drive. The fact that a driver has a valid prescription for the consumed medication is not a legal defense to an impaired driving charge.
First offense. A first drugged driving conviction is a class B misdemeanor and carries a $500 to $1,200 fine and a license suspension of nine months to two years. However, a first offense typically doesn't result in jail time. The offender will be placed on probation for up to two years and must complete a substance abuse evaluation and Impaired Driver Care Management Program (IDCMP).
Second offense. A second drugged driving conviction within ten years is a class A misdemeanor and carries 17 days to two years in jail, $750 to $2,000 in fines, and a three-year license suspension. If the court grants probation, the offender will have to complete the IDCMP and serve at least five days in jail (30 days if the prior offense was within two years). The driver must also maintain an ignition interlock device (IID) for one to two years.
Aggravated DWI. A DWI that involves speeding, child passengers, or a collision is considered an "aggravated DWI" and can carry increased penalties. In some circumstances, a DWI can even be charged as a felony.
Under New Hampshire's implied consent law, any driver who unlawfully refuses a chemical test will have his or her license suspended for 180 days. This suspension will be two years if the driver has any prior DWI convictions or test refusals. Suspended drivers may be eligible for early reinstatement after completing all treatment and sentencing requirements.