The head of Google's self-driving car program, Chris Urmson, sent a letter to the Department of Transportation on Friday outlining a proposal that would fast-track self-driving car technology and expedite the process of taking the technology mainstream. Current US law prohibits vehicles which cannot be driven by a human -- as is the case with the steering wheel-less Google Car -- from operating on public roads. And, rather than wait for these existing laws to eventually catch up to the technology, Google wants the government create a special permitting system wherein any auto manufacturer, having shown that their vehicle meets federal safety standards, could petition regulators for permission to sell them. For their part, regulators would be empowered to dictate usage limitations for the applicant vehicles based on prevailing safety concerns.