Throwing random obstacles into the chase works for movies, it'll work for you too. Give them a map of the streets between where they are and where they want to be, and give them as much space as possible. Then, fill that with interesting things like construction sites and dockyards for them to drive through. If you've ever played the Grand Theft Auto games, they're great at this. GTAIV has mid-city construction, elevated rails, airports, and all sorts of fun stuff for you to drive through, so there's a ton of ideas for places to set a car chase.
If you want more inspiration, go back through the James Bond films, they've got some choice car scenes, and Gone in Sixty Seconds (both of them) have some cool stuff too.
I also make sure that my characters drive in, over, through, and along buildings quite a bit, and powerslides give the party an intimidation bonus.