turtle identification

we've been having horrible thunderstorms all day, and while driving my mom found this young turtle that was trying to cross a busy road. i can't figure out what kind he his, though, but i though you guys might know. i want to set him free in the proper area if it's illegal for him to be captive in n.j.













thanks!

update: i released him out into a nice big wooded area near my house. i hope he grows into a nice big healthy turtle!