Catch me if you can
The Liberty City police aren't what they used to be -- or at least they aren't as aggressive about chasing you down at the lower one- or two-star notoriety levels. Once you've been made stealing cars, skipping tolls, charging barriers or (inadvertently) ramming police cruisers, you have to make your way past a radar search radius that shifts according to your proximity and visibility to the nearest law enforcement. Then, once you're clear, you must wait a half dozen seconds without being spotted to shrug off your "wanted" status. The cops move half as fast (or maybe the AI navigates GTA IV's environments half as effectively?) and don't toss up roadblocks as often, and your new GPS system lets you spot patrol cars or on-foot officers, making evasion almost too easy (until helicopters get involved at three stars and up, of course). Given the story's considerable length, the size of the city, and the fact that you can't save during missions, Rockstar probably nixed clingier cops, who might have frustrated gamers stuck between save points and dying repeatedly because of police interference. You can get plenty of action from the cops anyway, simply by strolling past initially blocked-off bridge barriers, which immediately blasts your "wanted" level to the maximum six stars ("suicide by cop").