The sight of Google's self-driving cars navigating the road is nothing new for Mountain View residents, but national tech media got whipped into a tizzy last week over news that a new fleet of auto-piloted cars will soon be hitting local streets.

In a May 15 blog post, Google announced it would begin testing out a new line of its autonomous vehicles, bringing as many as 25 new custom-built self-driving cars to the streets of the Mountain View in the coming weeks. Easily spotted on the road, the new cars feature a one-of-a-kind bubble shape that makes them resemble koala bears, according to some Google employees. Sitting atop the hood is the main eyes of the vehicle, a cylindrical laser scanner they joke looks like a bucket of chicken.

Making the new cars conspicuous might be part of the point. At this phase of the testing, engineers are focusing on getting human interaction with the autonomous vehicles. Google employees say they want to collect feedback from Mountain View residents on how the new prototypes interact with the flurry of activity on the road.

While the vehicles are sporting a new look, their brains are essentially the same as those of past models. For the last year and a half, Google has been testing about 20 Lexus SUVs equipped with self-driving software in Mountain View, logging about 10,000 miles per week. Before that phase, the same Lexus models were already being tested out on freeways. In total, the Google team has tallied more than 1 million miles of road driving.

Google spokeswoman Katelin Jabbari said this wasn't quite the watershed moment for self-driving cars, but it was the incremental milestone toward eventually bringing the cars to the consumer market. Working to that goal, it made sense to build new prototypes in-house, allowing the company's team to custom-build their own sensors and equipment for the vehicle, she said.

"If we're shooting for a fully self-driving car without human intervention, you might as well build something that's purpose-built for autonomous driving," she said. "The news here is that we're ready to start."

All of the self-driving cars will be traveling no faster than 25 mph. Jabbari indicated that the drivers may sometimes take the vehicles onto roads with a 35 mph speed limit. She couldn't specify any particular streets where the cars would be tested.

In this testing round, all of the new models will have a driver sitting behind the dashboard who will be able to override the autopilot of the car. The models come with a removable steering wheel, accelerator pedal and brakes, giving the driver the ability to take control if needed.

For right now, Google and other firms have permission from the state Department of Motor Vehicles to test-drive autonomous vehicles on public streets. State regulators are currently working to draft new rules for enforcement and liability issues on self-driving cars as various companies race to develop the technology.

In the meantime, that leaves local police in some uncharted territory on how to enforce the law, should any accidents arise. Recently, Google announced that its self-driving cars had been involved in 11 accidents to date, although the company noted that those incidents were all the result of human error.

Local Mountain View police officials say that, as of yet, no special measures are planned to enforce regulations on self-driving cars. Until new rules are issued by California lawmakers, a driver behind the dashboard of a self-driving car is still technically in control of the vehicle, said Mountain View Police spokesman Sgt. Saul Jaeger.

"As of right now, the vehicle code hasn't changed," he said. "From a law enforcement perspective, (self-driving cars) will continue to be under the vehicle code until a bill is passed, as far as how they're regulated."

Google employees haven't set a hard date on when their new prototypes would hit city streets, but they indicated it would likely be in the next two months. Leading up to that date, the company has already begun reaching out to local stakeholders to inform them about their progress.

At a Silicon Valley Bicycle Coalition meeting earlier this month, Sarah Hunter, the policy head at Google X, delivered a short presentation on the company's progress on self-driving cars. The technology has the potential to one day revolutionize automobile travel and improve road safety, she cheered.

"We're making the next small step forward, and we need to see how people react to these things," Hunter said. "I hope people will realize these cars are driving very, very slowly because they're very, very safe."