What is a Safe Age For Kids To Start Riding?

How old should your child be when they can start safely riding? There are too many variables to say for certain, including most importantly, your child's own agility and ambition to ride. The second most important issues to consider is your own judgement as to when you think the child will be responsible and safe enough to ride. You'll know if your child is ready.
When my Eldest son was two he got his first electric quad. I knew he would be safe on it because before he got that, he had a Big-Wheel which he promptly rode out the back door, down two steps and over the bars. He knew where he was going, I'm sure of it. After a very brief cry he got right back on it and rode it straight out the back door again, and made it to the grass.
I thought my son would have realized he shouldn't ride his Big-Wheel out the door because he would fall off and get hurt. Instead what he realized was that he just needed to keep his weight back a bit as he was descending down the steps, and hold on tighter.
That's why I say you need to consider when the child will be ready, and not just how old they are. Some kids will take to it right away, others may never want to ride. You can't force them, you can only nurture them and open doors of opportunity to them.
One thing's for sure, teaching kids just about anything at an early age is possible. It will play a big part in their over-all actions as the grow and participate in what ever activity they've learned. So make sure you teach them safety, respect and most important, to look where they're going.