John Markoff:

 That’s the best way to sum up my second ride in a Google self-driving car, on Tuesday.
 My first ride, now almost four years ago, included merging onto a freeway and navigating a sweeping flyover curve with all the dexterity of a human driver. This time our route was even more mundane, basically an uneventful tour through the city streets of a Silicon Valley community.
 Since it created the project in 2009, Google has upgraded its fleet of cars from Priuses to Lexus S.U.V.s, and the navigational hardware, positioned in the vehicle trunk, is now more compact. Also, when the driver switches into autopilot, it no longer makes a neat, swooshing Star Trek sound effect. Rather, an anodyne female voice informs passengers that the car is now driving.
 During the half-hour demonstration, part of a Google press briefing, the one noticeable behavioral quirk that the Lexus exhibited was that it seemed to change lanes with emphasis. There was no gradually meandering from one lane to the next as a human driver might. The Google Lexus was all business.