If a youth isn't supposed to be anywhere around a mower, then how does a young person learn to safely operate one? I'm completely in agreement with taking safety precautions and not taking risk for no reason. However, I can relate to previous posts that suggest that today's young adults are dangers to themselves and others because they never learned any common sense.
By 9 years old I could drive anything with wheels. At 11 I had my own shot gun leaning against the wall in my bedroom with my amunition on the shelf next to it. My father did these things at even younger ages. Every kid is different. But when a kid is ready to take on responsibility they should be taught and when ready, given responsibility.
I was reading "little house on the prairie" to my children last year and at one point "Ma" and "Pa" were out and Laura was left at home (I believe she was 9 years old) with her sisters. In the book she said it was OK because Pa's gun was leaning against the wall and all the girls knew how to use it if necessary. By this point in her life she also knew how to do just about everything that her parents did.
Each generation we become more brain washed that we can't actually do anything and we become less capable in the process. By the time kids are 12 or 13 years old they are acting out because they've never learned and never been given responsibility. By 12 or 13 some are biologically ready to be out on their own! It's not natural to be coddled until you're 18yo, or 21 yo, or 35 yo!
Today, I wonder how many people think it would be OK to leave a 9 yr old alone at home with a loaded gun? Honestly, it should only depend on if the 9 year old is ready for that. After all, I've met 9 year olds with more sense than most adults. However, all the youths I've met who are highly responsible have parents that take the time to teach them and then give them responsibility as they are ready.
BTW - my road doesn't have 18 wheelers on it. Max speed is 25 mph and you'd be hard pressed to exceed it much due to the sharp, frequent turns. Differential speed between a tractor and a car / truck is minimal.