Seriously. They're the ideal single-occupancy vehicle, much smaller engines and they're ideal for short, unladen journeys, which are the most pointless of car journeys. What's more, because they're only little, our roads will easily be able to accomodate them, which will eliminate congestion. Here's the killer part though - they have an irrestible attraction to the people most likely to buy huge 4x4s, ie. men with inadequacy problems. Everytime one shows up at the Hummer showroom, just say to them, "if you don't buy that 4x4, you can have this shiny motorbike! We'll even throw in some gnarly leathers and helmet with a flaming skull on it!". I guess someone will have to pay for all this, the government probably, but I'm 99% sure it'll work. Has anyone got Al Gore's email address?
On a more serious note though, does anyone here ride a bike, or a scooter? The idea's beginning to appeal to me.