Google is getting serious about its self-driving car technology campaign. In an effort to make the driverless car legal on U.S. roads, the Mountain View, Calif.-based tech giant was spotted showing off the robo-Prius on the streets of Washington, D.C. - just one day after Nevada became the first state to legalize autonomous vehicles.

According to U.S. News & World report, Google was in Washington to pitch the car to federal policymakers, and possibly take them for joyrides in one of the company's self-driving Prius hybrids.

The media outlet also reports that Google sank $5 million into a legislative lobbying tab in the first quarter of 2012 -- which is more than Apple, Facebook and Microsoft combined.

Getting lawmakers into one of the self-driving Priuses has become a major priority, according to Matthew Newton, editor of DriverlessCarHQ.com, a site dedicated to covering autonomous cars.

Google has been giving free rides to policymakers in California, Nevada and Florida, Newton told Wired from his home base in Melbourne, Australia. So it makes sense that they would do it in D.C. 

According to Wired, which continues to cite Newton, now that Google has largely cleared the technical hurdles of getting self-driving cars on the road, the next step is gaining public acceptance, and winning over policymakers.

But as Google has a considerable lobbying warchest and an equal amount of cultural clout, influencing politicians is not likely to be a problem.

According to a recent report in Politico, House Majority Leader Eric Cantor, R-Va., has already taken the self-driving Toyota Prius for a spin.

Cantor's visit to Silicon Valley last month was part of a GOP effort to gain access to that vast amount of campaign funds that tech innovators have at their disposal.

Google made the trip to Washington, D.C. attempting to go incognito, but was spotted by U.S. News and World Report science and technology reporter Jason Koebler.

Koebler eyed the Prius and his friend Allen Tran snapped a blurry picture with his camera phone.

The science and tech reporter told Wired that Tran took the picture and posted it on Facebook.

I saw it when I got home from work, Koebler said in an email interview. Twenty minutes later, I was riding my bike to the movies and saw it right around the corner from my house - just a weird stroke of luck.

Koebler said he tried to whip out his camera phone but wasn't fast enough on the draw, and the car drove away.

I was going to chase after it, Koebler added. There were two guys in the front seats [and I] wanted to talk about what they were doing, but I missed the light. Had I known Google would have been so hard to get in touch with, I would have tried harder. But they've been responsive to media requests in the past, so I was surprised I didn't hear back from them on this.

According to DriverlessCarHQ, the District of Columbia Department of Motor Vehicles said in a tweet that Google didn't inform the agency of its plans to operate the car in the nation's capital.

U.S News & World Report also said staff of the House Committee on Science, Space, and Technology had no knowledge of Google's plans, according to Wired.