The biggest change introduced in Burnout Paradise is the move to an open world, the streets of Paradise City (cue Guns 'N' Roses title track). The entire city is open at the start of the game, with the idea being that you can do whatever you want, whenever you want. Not all of the events are present at the start, mind you, and you'll have to put in a lot of time to unlock the game's roughly 75 cars, but you're never limited in the options before you.
There are bits of good and bad to this. The good is that the city design is great, offering up plenty of varying spots for you to race in and tons of hidden areas to find. There is no shortage of tucked away passages, underground runs and all sorts of cool spots to hit. You'll find jumps littered everywhere, including small ramps with kickers on the side to send you into a barrel roll, which are great for the Stunt runs (which we'll come back to in a bit).
The main downtown area of Paradise City is very reminiscent of the downtown tracks in the last couple games, while the western section of the city harkens back to the long, winding, countryside courses of past games as well. A couple of highways will put you dead in the middle of traffic and give you plenty of road to get up to speed on. Overall a great game.