资料：Google and Uber have grabbed most of the attention regarding the advent of self-driving cars, but on Sunday, Lyft threw down the ultimate challenge: A majority of autonomous vehicles for Lyft within a mere five years.

　　 The bold claim was made by Lyft co-founder John Zimmer in a post on Medium outlining his company's vision for the next decade.

　　"Within five years a fully autonomous fleet of cars will provide the majority of Lyft rides across the country," said Zimmer, indicating that early versions of such cars have been in operation in San Francisco and Phoenix.

　　Usually when tech founders lay out their vision, it’s typical to hear grand claims that almost push the boundaries of believability. That's what tech innovation is about. But in the case of self-driving cars, the situation is a bit more complicated.

　　Uber has already begun rolling out self-driving car tests in Pittsburgh and Google is hard at work on the same kind of solution on the West Coast. Therefore, talk of getting self-driving cars on the road is, at this point, less about the technology and more about logistics. We know Google has enough cash to triple down on any initiative it decides to tackle. And as the current ride-sharing leader in the U.S., Uber has enough market share-powered credibility that a future including self-driving Uber cars isn't unrealistic.

　　Today there are some internet-based ride sharing system but to overcome the critical mass the system has to be real-time, automated and extremely easy to use.

　　However in the case of Lyft, which continues to struggle against Uber (one report claims that Uber has over 80 percent market share in the U.S.), such a short timeline toward rolling out a fleet of self-driving cars seems somewhat ambitious. Nevertheless, Zimmer continues his vision essay with even more bold predictions.

　　"By 2025, private car ownership will all but end in major U.S. cities," says Zimmer, a prediction that, if it turns out to be true, would mean it would take just eight years for the majority of the human-driven cars on U.S. roads to disappear. Possible? Sure. Likely? Eight years seems like, once again, a bit of wishful thinking on Zimmer's part.

　　Remember, it hasn't even been 10 years since the arrival of the iPhone, and as recent events prove, smartphones are still a category that can yield catastrophic results if not done right. And those are just mobile devices, not vehicles entrusted with transporting and protecting human lives.

　　To be fair, Zimmer's essay does offer some facts and figures in an attempt to back up his positions, but much of it doesn't appear to take into account variables such as the heavily embedded interests of automobile companies still relying on consumer auto sales, as well as the many legal and roadway logistics that will need to be addressed in order to bring about this massive transformation in such a short time.

　　Oddly, Zimmer's vision does little to address the millions of human jobs that will be lost once self-driving cars displace not only taxi drivers, but truck drivers.

　　"We believe that in the first five or more years following the introduction of autonomous vehicles, the need for human drivers will actually increase, not decrease," writes Zimmer. "When autonomous cars can only solve a portion of those trips, more Lyft drivers will be needed to provide service to the growing market of former car owners," writes Zimmer.

　　But what about after five years, when autonomous cars can provide full service? What about the human drivers? The pushback from human drivers losing work will likely be another, major ripple in the evolution of self-driving cars, as well as other automated systems entering U.S. society in coming years.

　　However, none of these logistical issues diminish Zimmer's ideas. His vision of the future of autonomous vehicles seems quite logical and in step with most who work in and watch the space closely. But the speed bump in accepting his vision wholesale is his ambitious self-driving car timeline in general, and for Lyft in particular.

• A.At almost unprecedented moment in history, we should reach our potential to decide whether to take the right path
• B.At almost unprecedented moment in history we should reach our potential to decide whether to take decisive action
• C.At almost unprecedented moment history,we should reach our potential to choose the right answers to all the problems encountered by us
• D.At almost unprecedented moment in history we should our potential to realize the advent of the era of self-driving cars