One of eight prototypes, the blue self-driving Toyota Prius Google brought to D.C. — no, it didn’t drive itself here from California; I asked — only really stood out because of the constantly-rotating laser mount that sits atop its roof. This laser — along with sensors on the front and rear fenders — constantly feeds information to the car’s computer, telling it when, say, a pedestrian crosses into the street or a Maryland driver is aggressively cutting into a lane. The car also relies on constantly updated maps that tell it what a particular speed limit is and how to drive itself from point A to point B.

After a morning briefing, D.C. Council members Mary Cheh (D-Ward 3) and Tommy Wells (D-Ward 6) were invited for a drive around the block. After returning, Cheh said that while the car drove much like any other would, it was “uncanny” when she realized that it was driving itself. And how did she know? She said she asked the Google engineer behind the wheel to express himself with his hands and turn around to talk to them. He did — and the car continued driving itself without interruption.

OK, so it’s really cool, but what’s the point? Cheh and a Google engineer were peppered with questions as to why a self-driving car would be necessary or useful. First off, they said, was safety. In 250,000 miles worth of testing, said the Google engineer, none of the self-driving cars have gotten into accidents. For Cheh, the value of this is inestimable — not only in terms of lives saved, but also in a hopeful future where traffic isn’t backed up on Interstate 66 because of early-morning fender-benders.

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Martin Austermuhle blogs at DCist . The Local Blog Network is a group of bloggers from around the D.C. region who have agreed to make regular contributions to All Opinions Are Local.