Whilst the following story is from california, and only mentions cars so far, would this be a good idea to have also on bikes, say, to tell that car following to close to back off, e.t.c. Or is it just another one of those things where governments are taking over.... http://www.smh.com.au/technology/te...n-drive-your-messages-home-20100623-yz6x.html LOS ANGELES: California is considering using digital car number plates, which would switch to advertisements when vehicles are stuck in traffic, as a way to raise money to tackle its $US19 billion ($21.6 billion) budget deficit. The electronic plates would look like standard plates when the car was in motion. But when a car has stopped for more than four seconds, in a jam or at a red light, scrolling advertisements would be displayed to people sitting in the vehicles behind. Advertisers would buy space from the state's Department of Motor Vehicles. Drivers would also be able to have their plates show personal messages, such as the name of their favourite sports team. Obscene messages would not be allowed and a section of the plate would continue to show the registration number at all times. In emergencies the plates could also be used to display public service announcements such as missing children alerts or traffic information. A state senator, Curren Price, said California wanted to be the first to introduce the technology. A bill being considered by state politicians would allow for safety tests before its introduction. Senator Price said: ''We're just trying to find creative ways of generating additional revenues. It's an exciting marriage of technology with need, and an opportunity to keep California in the forefront.'' A company called Smart Plate in San Francisco is developing the plates and sees them as an outlet for advertisers and drivers. The company's chief executive, Conrad Jordan, said: ''The idea is … to create a platform for motorists to show their support for existing good working organisations.''