Transport used to be easy. Start off with the tricycle, then graduate to two wheels before you finally get to something with an engine (normally something rusty and purchased on eBay). When you hit middle-age you're allowed to buy a convertible or a Harley. And then finally, you're reduced to the stairmaster.

Now it's all so complicated. It's not just 4x4s that are coming in for stick, but anything with an 'emission' is deemed evil.

But before you start strapping on your elbow pads may we point you in the direction of Zipcar, the world's largest car sharing service. Launched in the UK today, it's similar to Streetcar - clean cars, available by the hour, pick up in several locations around town, etc - but has a fleet that includes everything from a luxury Beemer to a speedy MINI (we love), and they're all as 'green' as can be so there's no stain on your environmental conscience.