Living in new york and being pretty involved in that type of stuff, more on the spectator side. it isn't that organized. there are some spots you can go to on the weekend and there might be like 100 cars there and u can get into some random races. eventually the cops will come and every one runs to their cars and rush onto the highway. i personally casual walk back to my car and sit there. cops usually go for the ones running anyway. 15 mins later everyone back at the spot. this continues until someone crashes, blows up leaving anti freeze all over. sometimes the cops just give up and park a ambulance close. for me its interesting watching it; is it dangerous of course just as dangerous as spectating a rally.
if its a race for like money, 3000+ they usually do that on a highway and they shut it down for like 20 mins to do it. i specifically don't go when its some muscle car because those things don't go straight