Google's fleet of modified Lexus SUVs equipped with autonomous vehicle technologies could soon become a familiar sight in Kirkland, Wash.

The company has been given the green light to test its self-driving vehicles in the state—which has now become the third in the country to do so. In addition to Washington, Google has received permission to test its self-driving vehicles in California and Texas.

According to Google, Kirkland offers an ideal location for the company to test its autonomous vehicle technology in rainy and wet weather conditions. The city's hilly terrain also offers an opportunity to test vehicle sensors at different elevations and angles, the company said in a statement.

Google has been driving a single Lexus RX450h SUV equipped with the company's autonomous car technology in and around Kirkland for the past several weeks in an effort to create a detailed map of the area and to identify features like traffic signals, curb heights and "keep clear" zones.

The information gathered from the exercise will help as the company begins regular testing of its vehicles in Kirkland, Google said. According to the company, Kirkland will become the second location after Mountain View, Calif., where Google will conduct regular testing of its autonomous vehicles, though it has been given the go-ahead to do so in Austin, Texas, as well.

For Google, such testing is crucial to its ability to deliver autonomous vehicles that meet federal and state standards for safety. California—where Google's headquarters are and where the company has been doing most of its testing—last year made clear that it is unwilling to let Google or any other car manufacturer operate fully autonomous vehicles on its roads for the foreseeable future.

It's unclear whether other states will follow California's lead in mandating a much more phased introduction of autonomous vehicle technology than Google had perhaps hoped for.

Google, which has made no secret of its ambition to deliver both semi-autonomous and fully autonomous vehicles over the next few years, has been conducting extensive tests of the vehicles over the past few years.

The company has compiled a voluminous set of data from its experience testing its fleet of modified Lexus vehicles and its own fully autonomous vehicles over some 1.5 million miles. The reports have offered a far more detailed look at its progress in developing and delivering the vehicles compared to the several other manufacturers engaged in similar initiatives, including Mercedes Benz, Nissan and Tesla.

For example, a recent safety report that Google submitted to California's Department of Motor Vehicles shows that over a 14-month testing period its autonomous vehicles had to hand over control to a human driver on 272 occasions to avoid a safety issue. Its vehicles had to disengage from autonomous mode on 69 other occasions to avoid potential collisions with other vehicles during the same period. In contrast, Mercedes Benz recorded 491 manual disengagements with just one vehicle over a distance of 1,300 miles.

Details on Google's autonomous vehicle program released recently by the company show that it is currently testing a fleet of 22 modified Lexus RH45h SUVs, and 33 prototypes of its own fully autonomous vehicles. Most of the testing not surprisingly is in Mountain View.