I have the same as Gerda, and that was going to be my suggestion. I tell my toddler that it's a puppy hug pack and he doesn't speak well or listen well but he likes the puppy pack very much when we go out. He will bring it to me when he wants to go outside.

I have a small animal shaped backpack that also has a strap that goes around the waist and a strap attached on the side that the parent can hold, so the child cannot run off. Someone got mad at me once, telling me children were not dogs to be put on a leach. The alternative is her getting hurt seriously. She usually bolts out of the blue and sprints like a professional runner and it's hard for me to catch up.

My twins BOTH did this and they would never run in the same direction! As a result we didn't go a lot of places unless we had one adult to one kid. In public they had to hold my hand or we would just leave. In super busy places like airports we put them in a stroller or used harnesses - and jerks who wanted to stare were free to do so :)
The best thing we did to actually curb the behavior was teaching them to play "Red light, Green light". Lots and lots and lots of over the praise when the actually stopped when we said "red light!" It took a couple of months but now they can walk with me most of the time without holding hands - even though I still want to because I'm still so paranoid about them running off!

I still hold my 9 year olds hand firmly.

My daughter was ADHD & FAST! She could go from 1 to 60 in a blink of an eye! After one particularly harrowing experience with a busy street, I bought a kid harness.

She was so active, she refused to sit in the cart so the harness kept her close and gave me major peace of mind. Hope this helps!