The U.S. Department of Transportation is starting to move into the 21st century as it looks to update its Federal Motor Vehicle Safety Standards (FMVSS) to address self-driving and advanced car technology.

Not surprisingly, the FMVSS—which dates back to 1966—assumes cars will be driven by human occupants. But advances in autonomous car tech means that won't always be the case. As such, existing safety standards make it nearly impossible for automakers to get cars with advanced, automated features certified. That includes things like theft and rollaway prevention, as well as light vehicle brake systems.

Similarly, the FMVSS requires service brakes to be "activated by means of a foot control." But Google's self-driving Little Tikes Cozy Coupe lacks a steering wheel and pedals, while other car makers are eyeing the omission of manual controls and alternative cabin layouts.

If the FMVSS is not updated, self-driving cars "may face significant challenges to certification," according to a new 148-page report written in conjunction with the Volpe Center.

National Highway Traffic Safety Administration (NHTSA) head Mark Rosekind says the report is "a great first look" at how to incorporate autonomous car tech into traditional vehicle regulations. "It also shows there are few current restrictions on some automated vehicle concepts, which highlights the need to establish clear expectations for their safe operation.

"At the same time, for other vehicle designs, the agency has more work to do to ensure the safety of new innovation," he added.

NHTSA plans to hold public meetings in Washington, D.C. (April 8) and California (TBD) to gather input on a series of safety-related concerns.

A U.S. Senate panel will hold a hearing next week to talk about the future of autonomous vehicles and potential regulatory barriers, as well, Reuters said.