Americans welcome self-driving cars:study

56 percent of US respondents have positive opinions of self-driving vehicles, according to a new study in media Wednesday.

The technology sounds like science fiction -- 29 percent of Americans surveyed have not heard of it before the study.

But self-driving cars are coming, and Americans are getting on board.

Google(GOOG)unveiled a self-driving prototype in May. The system probably won't be widely available for five or six years, but executives have predicted that one day "a significant number of cars will carry Google technology.

By 2035, sales of self-driving cars will reach 11.8 million, or 9 percent of the 129 million global auto sales expected that year,according to a forecast published recently by auto industry consultant IHS Automotive.

California, Nevada, Florida and Michigan have passed legislation allowing the testing of self-driving cars on public roads, and the National Highway Traffic Safety Administration has issued a series of recommendations on the issue as well.

Those surveyed by the Michigan researchers said self-driving cars were likely to yield a variety of benefits, including fewer crashes, decreased emissions and lower insurance rates.