A self-driving Audi A7 traveled from Silicon Valley to the 2015 Consumer Electronics Show in Las Vegas last week, while Mercedes-Benz and Ford also made announcements about autonomous technology, reports Time.

The 550-mile road trip took two hours, traveling south down Interstate 5. Traffic was heavy, but the autonomous Audi kept up with traffic, changed lanes and handled itself on the road perfectly -- even at speeds of 70 mph. The driver sat with hands in his lap and feet tucked out of the way.

The trip exemplified how far Audi's technology has evolved. The A7 uses sensors, radars and a front-facing camera as "eyes" and advanced computer technology to intelligently negotiate traffic. The driving system currently works only on the freeway. It cannot handle poor lane markings, traffic jams or construction zones. If the car reaches a construction zone or the end of a freeway, a voice commands the human driver to take the wheel. The driver has 10 seconds to act or the LED warning lights change from blue to amber, and lastly, flashing red. The driver simply grabs the wheel or applies the gas or brake to resume control.

The Audi A7, described as a "Stage 3 autonomous car" (there are five stages, the fifth being a totally robotic taxi cab), is one of many self-driving cars being tested on U.S. roads. Mercedes-Benz and Tesla also are testing prototypes on national roadways.

"We won't see piloted driving on the freeway until the next decade," said Jörg Schlinkheider, head of driver assistance systems for the VW of America. "And fully autonomous driving with no human assistance is far, far away."

The federal government does not yet have specific laws pertaining to self-driving cars. Self-driving automakers are hoping federal agencies will step in so that automakers and drivers won't have to deal with 50 different sets of regulations in the different 50 states. Currently, individual states are creating their own mandates. California is the most proactive, allowing carmakers to test cars under a specific set of rules.

One of California's rules is that drivers receive training that includes how to turn the system on and off, handle emergencies, and in which circumstances the "Audi piloted driving" could be used.

According to Time, Audi still needs to develop a program that allows the self-driving car to operate in stop-and-go traffic.