New Hampshire’s substance abuse crisis is often linked with a single type of drug: opioids. But another illicit drug is rising in use. That’s methamphetamines.

Over the past three years, meth cases have more than doubled each year in the state.

NHPR’s Paige Sutherland reports from one Southern New Hampshire town where meth use is raising particular concern.

Listen to the radio version of this story.

I’m in a car with an undercover police officer.

“So I’ll basically give you a tour of what each of the hotels are, just so you have an understanding of the proximity that they are to each other, the proximity that they are to the highway," said an undercover informant.

We slow down in front of a collection of budget hotels, just a few hundred feet from the highway exit here in the town of Merrimack.

The hotels are nothing special, but they’re increasingly popular with visitors the residents of this town would rather not have.

“So, when people are driving by they know they can see from the highway, they know they are getting off the exit and even without GPS you are finding your way to the hotel easily.”

This is ground zero for the meth trade in this otherwise quiet community.

From the outside, the hotels don’t look like “drug dens” – the buildings are well kept, no trash lying around. One’s even brand new.

But in the past six months, the police have visited these hotels hundreds of times for drug activity, including three methamphetamine arrests in a single night last month.

"I just debriefed somebody a couple weeks ago, their exact words is, they referred to it as meth central – quote unquote – 'meth central,'" the officer said.

Merrimack Police Chief Denise Roy tells me that part of the problem is geography. As police in Southern New Hampshire’s larger cities have increased anti-drug sweeps, many dealers and users have fled to smaller towns in the area.

“So, it’s almost like a free-for-all, come to Merrimack you can do anything you want. There’s three officers, maybe one of them will catch you.”

These hotels are the perfect spot for dealers looking for convenience. They’re located between Nashua and Manchester, right off the highway and offer extended stays

And since there’s four in town, the hotels are constantly competing by lowering their nightly rates.

Since the fall Merrimack’s officers have made nearly 50 drug arrests, mostly involving meth, surpassing heroin and fentanyl arrests.

Unlike heroin and fentanyl , meth is an upper and one of the major side effects is increased energy and aggression.

“They are lawless – some of these people are lawless. They run from the police, they take off on foot, they take off in cars, a couple of our officers have been hurt, one of them had to go to the hospital because he was injured," Chief Roy said.

Since the recent uptick in meth in Merrimack, other crimes have spiked as well. According to police records, prostitution, car thefts, and home burglaries are all on the rise.

Merrimack is not alone. Meth use has been increasing statewide. Last year the state’s crime lab tested more than 830 meth-related arrests, compared to just 50 three years ago.

I ask Tim Pifer of the state’s drug crime lab what’s behind that increase. He says it comes down to economics.

“They realized that some of the mixtures of the fentanyl street drugs were too pure – they were killing some of their repeat customers and obviously it is a business to them so they were trying to get some of their users addicted to another drug.”

But users are also taking notice of heroin’s lethal potency. Many are seeking other alternatives, that are less likely to kill them says Special Agent Jon DeLena of the Drug Enforcement Agency.

“We’ve had some instances where people have said they are trying to make the switch because it is safer.”

In New Hampshire, fentanyl killed nearly 300 people last year alone, compared to 10 people from methamphetamines.

Meth might not be as deadly but long-term effects can include paranoia, depression, and heart problems.

Back in Merrimack, the police department continues to make frequent meth arrests. But come April, they’ll have a new specialized drug unit on the streets aimed at tackling this meth trade.