I explain that we need to keep him safe reminding him of running in the street, parking lots, down stairs, and getting lost. He said he can keep himself safe and wont get lost and repeats that he needs to go out on his own sometimes.
It sounds like you are a finding a good balance between safety and sympathy. I would encourage him to explore 'in his imagination.' For example, I would encourage him to write a nonfiction book about safety for 3 year olds. As if he was writing for an audience of 3 year olds to learn the rules of what is safe to do and not to do. That way he gets to experience freedom, satisfy his need to be seen as an athority, and you get to see what his ideas about safety actually are. It may be that he can safely cross a quiet street and once you know what he is ready to handle you can give him some bigger opportunities.
Then you can encourage him to do some fictional adventure stories about kids who didn't follow the rules.
I would also load him up with household responsibilities, so he can feel 'responsible' - he may be able to do some laundry chores, some kitchen chores. A friend told me that the trick to getting children to do chores was to let them do jobs that they were a breath away from being able to do successfully. I didn't have much luck with it, but it sounds good.
As for leaving the park, that's a tough one. I think I was still wearing a sling at that point, and offered the choice:Do you want to leave like a big boy or do you want Uppies? If mine couldn't or wouldn't leave 'like a big boy' then it was 'up and into the sling.' I only like to play games if the deck is stacked in my favor. We were lucky that there weren't times when I'd have to do a punishment later. (Usually the problem was that he'd throw a pebble at a friend and so it was time to leave in a 'up and into the sling' way. Suprising that it took such a bright boy so many times to learn, but learn he did.) I also had a watch with a timer, so I would start the whole thing by offering to go now or in 5 minutes. We called it his 'time to do the last thing.'
The next town over had an 'indoor sports center' which was a contained space with a bubble and a giant playscape inside where he could run out of eyesight safely.
Good luck!
Grinity
