If you live on a busy street, you have to be particularly careful. Give your son lots of supervised practice - lots. See how well he uses his judgment. Can he wait patiently for cars that are in the distance to pass safely by? Does he seem to see those cars that are a bit far off? Is this child impulsive, impatient or otherwise immature? Each child is different. However, I'm sure your husband loves your son as much as you do and wouldn't want him to get killed! See if the other young children on your block are allowed to cross by themselves - how old is the youngest of the bunch? Determine a norm. But do trust your instincts as well. You can also run this question by your pediatrician and others who deal with kids like the school principal and the mothers that you know. Don't be the only one in the neighborhood who lets their child cross alone. However, don't be the only one in the neighborhood who doesn't let their child do it either. As for the lawn mower, the issues and solutions are similar. Young kids can get hurt with lawn mowers. Care is required. Lots of supervision is necessary. Maybe let him do a small section of the lawn while you watch until you feel that he is strong enough and competent enough to manage more.   Sarah Chana