He won't last long on the street if he is unfamiliar with the environment, will either be run over, scared away, catch an illness or attacked. He needs rescue. So get out your carrier and get him to go in, if he wont let you pick him up and put him in you may be able to lure him with treats. Get him to a vet to get them to scan for a microchip to find out if he has an owner - he may have been stolen and dumped - I've heard of a few lousy neighbors who do this when an indoor-outdoor kitty poops in their yard.
Once he is safe indoors if no chip put up on Tabby Tracker and Petfinder and even Craigslist when, where and description of kitty and ask responders to send you a pic to compare it to kitty so you can avoid bunchers, dealers and collectors.
If in 2 weeks you have no leads as to prior home then contact local rescued who may have room for a friendly, healthy kitty. Do NOT bring him to the city shelter AC&C or ASPCA as they dump at the AC&C. Try smaller rescues who can help like Sean Casey, BARC, KittyKind, City Critters, Mighty Mutts, there are tons out there!
You can't change the world but you can change the world for this kitty.