Sobriety checkpoints are one of the most debated aspects of DWI enforcement law. Laws regarding roadblocks set up in order to catch impaired drivers vary from state to state. Some state courts have ruled sobriety checkpoints as unconstitutional. Even in states where they are used regularly, some feel that they are a violation of the fourth amendment which protects against unreasonable search and seizures. A sobriety checkpoint occurs when police set up a roadblock at a specific location and stop a random pattern of vehicles traveling through that area. As drivers are checked for license and registration, police officers are trained to look for evidence that they may be under the influence. In many states, these roadblocks are performed routinely along with DWI saturation patrols as a way to enforce DWI laws.

In New Hampshire, roadblocks are legal but only under certain conditions. The process of how today's current laws came to be began on the early 1980s. In April of 1984, police in Concord, New Hampshire drafted a list of rules for performing sobriety checkpoints which they referred to as "Standard Operating Procedure" (SOP). They involved making sure the stops were minimally intrusive and stated that the purpose of the stops should be to catch impaired drivers.  From April 1984 to October 1984 there were 47 roadblocks setup by police in that city and a total of 1,680 vehicles were stopped. Of all of these roadblocks, only 18 DWI arrests were made. During that same period of time, Concord police also made 175 DWI arrests by patrolling as usual.

In the New Hampshire Supreme Court case State versus Koppel in 1985, the defendant was arrested for DWI at one of these checkpoints in Concord. His attorney argued that the evidence of his arrest should be suppressed because it was obtained in an unlawful manner i.e. the checkpoint violated his state and federal constitutional rights.

The New Hampshire Supreme Court ultimately ruled that DWI checkpoints were a violation of citizens' rights under the New Hampshire Constitution. The court stated that because there were alternate methods that were actually more effective at catching DWI drivers, there was no reason to justify the roadblocks. It was determined, however, that checkpoints could be used by police if they are approved by a judge. In 1997 New Hampshire passed a law, RSA 265:1-a, stating that sobriety checkpoints could be used only when law enforcement petitions the Superior Court and gets them to issue an order authorizing the use of a roadblock. This way, the court feel that police will only work to get a roadblock set up when they feel that it will be the most effective way of enforcing DWI law.

In New Hampshire, roadblocks are legal but only with a judge's approval. Because of this law it is difficult for law enforcement to perform DWI checkpoints. A person who is stopped and arrested for suspicion of DWI at a roadblock should speak to an attorney immediately in order to make sure that the stop with lawful.