Well, mine was never a "runner". As a toddler, he'd get out of the car, stand there & kind of wait for me to take his hand.
Playing in the yard/shooting hoops/etc. I was "comfortable" with him SAFELY crossing the street independently to get a ball, etc. by 7 or 8ish.
He's a "head-in-the-clouds" kind of kid and I didn't feel he was aware enough of his surroundings until then.
At 9? He'd NEVER hold my hand crossing the street! LOL But very, very occasionally, (remember--head in the clouds?) he'll absentmindedly reach for my hand at the mall, etc. then quickly get a horrified look on his face & pull it away!