Need for Speed: Rivals is a collection of everything that is great about Hot Pursuit, High Stakes and Most Wanted, refined into one superior game with a slant of its own.
There is a storyline to Rivals, but it's not one you'd want or need to take any notice of. All you need to know is that you can drive as a racer outrunning the cops, or a cop pursuing the racers. You can even swap between the two to keep things interesting.
What makes Rivals stand out above the rest is All-Drive, a live driving environment similar to that used in Test Drive Unlimited. You can be a cop chasing a speeding fugitive along a mountain pass, dodging casual drivers, when another speeder comes in the other direction being chased by two cop cars. That speeder could be a friend of yours, or one of the cops, too. You then have the option of slamming on the handbrake and helping them with the chase.
Pulling up next to another high-performance vehicle will initiate a race anywhere on the sizeable map. It's a straight A-to-B race and you can record top speeds and times for others to see live in their game at checkpoints.
The points you earn by completing objectives can be used to upgrade or unlock vehicles. Understandably though, the handling and performance of each doesn't really vary with the typical arcade-style driving.