In recent weeks, three episodes of people arrested for driving while under the influence of drugs have been reported in the local papers.

One driver told police it was National Marijuana Day and he had been smoking all day. He also indicated that marijuana “slows me down and I drive better.” I assume that’s his reflexes he is talking about. These reflexes are what drivers rely on when something happens, like a child darting into the road chasing a ball.

In another case, an Uber driver was arrested in Athol at 1:45 p.m. He was high as a kite. When questioned by police, he told them he was in Fitchburg picking up a fare for 9:30 a.m. Is this stuff really harmless?

Now we learn that the driver who struck and killed State Trooper Thomas Clardy in March was on his way home from picking up his medical marijuana, three joints, all smoked before he crashed on the Mass Pike, killing a trooper, making a wife a widow and taking a dad away from seven kids.

We have not yet legalized marijuana, but people are so emboldened by the talk that they are lighting up, driving high and forgetting where they are or what time it is. Young people, like the man who killed Trooper Clardy, are going to medical marijuana clinics claiming a number of different ailments as a diagnosis and grabbing legal joints, and then driving high. Now a man is dead because of it. Can we stop this madness?

The marijuana that legalization advocates want to make available in Massachusetts is not your grandparents’ marijuana. Marijuana typically available when I was a kid had a THC level less than 10 percent. The marijuana available today has THC levels closer to 30 percent, much stronger than anything available 30 years ago.

Young people today are also more creative and daring than we were as kids. They are involved in a practice called “dabbing” where the THC of a marijuana plant is extracted, cooked and smoked. This allows for a high with 80 percent to 90 percent pure THC. Smokers of marijuana from “the old days” have never experienced anything like this, yet this is what will be legal. Also legal will be the candies and cakes laced with THC that kids could be attracted to, as has happened in Colorado, where many kids have been hospitalized due to marijuana exposure through laced candy.

So now that we are clear about what will be legal, let’s see how this fits in to what we know. We know the average age of first time marijuana use is 12.8 years (just shy of the 13th birthday). That’s the average. This means some kids younger and some kids older. We also know that marijuana is harmful to the brain, particularly the young, developing brain. What do you think the impact will be when it is as easy for a 12-year-old to get 80 percent pure marijuana as it is for kids to get their hands on a pack of cigarettes?

We know that there is a startling reduction in the number of kids who think marijuana is harmful. Since legalization efforts have gained steam, more and more young people interpret this as a message that marijuana is not harmful to them. A national study found that 12th-graders’ perception of marijuana as harmful has dropped from 65 percent in 1994 to 36 percent in 2014. As marijuana gets more potent, kids view it as less harmful — frightening!

Marijuana is harmful, it is addictive and its use can lead to death. Just ask the Clardy family. As your elected public safety leader in Franklin County, I encourage you to join me in voting against any legalization effort.

Christopher J. Donelan is sheriff of Franklin County.