It seems that many in the US have gone to pot — marijuana that is.

The legalization of marijuana, or cannabis, is a rising trend in the United States.

But what will be the impact on health and highway safety?

While several states decriminalized recreational marijuana use starting in the 1970s, the all-in trend picked up momentum in 2012, with Colorado and Washington becoming the first two states to legalize marijuana for recreational use.

The medical use of cannabis is legal in 33 states. Recreational use is now legal in 10 states (Alaska, California, Colorado, Maine, Massachusetts, Michigan, Nevada, Oregon, Vermont and Washington).

Pot was always around when I was in high school and college, but it also was illegal.

I'm not going to argue whether it should be legal or not. But I have wondered mainly about two things.

One, isn't pot smoking, well, smoking?

Haven't we spent the last three decades or so snuffing out tobacco smoking? We were told that smoking was cool, with magazines featuring ads for the rugged Marlboro Man, and svelte models holding Virginia Slims, a skinny cigarette marketed to women.

There was smoking in workplaces, restaurants, airplanes and basically everywhere. Now we don't even allow smoking in parks.

Wasn't the main point in the drive against cigarette smoking is that it causes cancer, mainly lung cancer?

Does lighting up a joint every day put you at risk for cancer?

A federal review of marijuana research in 2017 found the lung health risks of smoking marijuana "far lower than those of smoking tobacco".

However, the American Lung Association says that "whether from burning wood, tobacco or marijuana, toxins and carcinogens are released from the combustion of materials. Smoke from marijuana combustion has been shown to contain many of the same toxins, irritants and carcinogens as tobacco smoke.

"Smoking marijuana clearly damages the human lung. Research shows that smoking marijuana causes chronic bronchitis, and marijuana smoke has been shown to injure the cell linings of the large airways, which could explain why smoking marijuana leads to symptoms such as chronic cough, phlegm production, wheeze and acute bronchitis."

New York City runs some graphic television commercials of people who have suffered terrible, disfiguring consequences from smoking.

At a recent hearing about New York state's potential legalization of recreational pot use, New York City Councilman Republican Peter Koo said: "We're trying to stop people from smoking all kinds of things. Why do you want to legalize marijuana?"

As a former cigarette smoker, New Yorker Gary Smith is dismayed that his home state might legalize pot-smoking. He fears the respiratory risks of marijuana smoking aren't fully known.

"It's crazy that the government, in order to raise (revenue from) taxes, they're permitting people to suck this stuff into your lungs," says Smith, 78, an accountant from Island Park.

(Not that smoking is the only way to ingest marijuana. There are pot brownies.)

Point No. 2.

A popular anti-drunken driving campaign uses the slogan "Buzzed driving is drunk driving". The premise is that if you have a couple of beers — enough to catch a "buzz" but not to make you falling down drunk — you shouldn't be driving. (That is true, because the blood alcohol level (BAL) in US states that would make someone an intoxicated driver is 0.08, which for most people is a couple of beers or a glass of wine.)

The National Institute on Alcohol Abuse and Alcoholism found drivers with blood alcohol levels of .05–.08 are seven times more likely to be in a fatal crash than those not drinking.

On Jan 1, Utah became the first US state to lower the BAL for DWI to .05. California, incidentally in 1996 the first state to permit medical marijuana, and New York also have introduced legislation to reduce BAL to 0.05.

According to a National Highway Transportation Safety Administration (NHTSA) roadside survey from 2007-2013, there was a 48 percent increase in weekend evening drivers testing positive for a form of cannabis, whose principal psychoactive ingredient is tetrahydrocannabinol (THC).

"Certainly we see the problem in states that allow for medical or recreational access, but even in states that are not allowing access," said Heidi King, deputy administrator of the NHTSA.

A recent survey from DriversEd.com found 21 percent of American motorists admit to having driven while high, CBS Miami reported. Survey data found that 58 percent said that legalized marijuana use would lead to increased danger on roads, with 91 percent responding that marijuana can impair driving, the website reported.

Eighty-two percent said that if a driver who arrived to pick them up was high, they would not get in the car. Eleven percent said they had gotten in a Lyft, Uber or other ride-share service and suspected the driver was stoned.

So, is stoned driving impaired driving?

On April 30, the NHTSA and the Ad Council launched a national campaign to encourage people to recognize that when they're high on marijuana, they shouldn't drive.

The video features the tagline, "If You Feel Different, You Drive Different".

Despite the legalization of marijuana in more states, driving while impaired by any substance is illegal in all 50 states and Washington DC.

"Marijuana can slow reaction times, impair judgment and compromise the cognitive skills needed to drive safely," said Heidi R. King, NHTSA deputy administrator.

The Associated Press contributed to this story.