The street racing scene in Tokyo is very well known, the Japanese cops generally leave them along during the nights and early morning as they know
sooner or later these guys are going to end up at a hospital nearby that specializes in high speed accidents! The long expressway he is talking about
would most likely be the 'shutoko' which covers nearly the entire stretch of Tokyo (which is quite long!). Daigoku another famous areas where these
"Street racing" people hang out, this is just outside Yokohama.