Hot Wheels Unleashed will have a track editor, which is great news for anyone who wants to play it like a 21st century Stunts (opens in new tab) (me). It's the exact editor used by Milestone to make the game's out-of-the-box tracks. You'll choose an environment, lay down your track, sprinkle it with boost pads, obstacles and too many loop-de-loops, and then share it online to rapturous praise.
The video above gives you a run-through of how the editor works, and if you've dabbled in building tracks for Trackmania it'll look familiar. The environments are the same ones you'll see in the main game, with obstacles baked in, but you're free to go nuts otherwise. There's also a blank slate environment called the Track Room, if you're not fond of having to build around a giant skatepark or humungous college campus.
Tracks can be customised down to their colour schemes, and there's a range of objects to use (promisingly, it looks like you can make giant boost pads). But rest assured, community tracks won't be littered with impossible feats: In order to upload a track you have to complete it.
Phil went hands-on with Hot Wheels Unleashed (opens in new tab) recently, writing that it's reminiscent of the "glory days of mid-budget racers," which is music to my ears.