The UK is the latest country to allow driverless cars to hit the highway. The country will start allowing the cars on public roads beginning in January, the BBC reports. California, Florida, and Nevada have already let driverless cars zoom through the streets, as has Japan. Britain will start with a testing period that could last three years, the AP adds. Some of the cars will have drivers on hand just in case; others won't be carrying anyone. The country is also rewriting its road rules to accommodate the vehicles.