This Two Lane Wide Chinese Bus is Either Brilliant or Insane by David Z. Morris @FortuneMagazine May 29, 2016, 4:03 PM EDT E-mail Tweet Facebook Linkedin Share icons After several years in limbo, one of the most odd and ambitious attempts to address China’s urban pollution and congestion problems is showing signs of life. The so-called “straddling bus,” the brainchild of designer Youzhou Song, would arc over two lanes of traffic, carrying up to 1200 passengers while leaving smaller vehicles free to drive underneath it. The concept—officially known as the Transit Elevated Bus—was showcased last weekend at the 19th China Beijing International High-Tech Expo, and Xinhua News reports that a demo bus is under construction, to begin testing in Quinhuangdao City this summer. Get Data Sheet, Fortune’s technology newsletter. The bus would either run on embedded rails on both sides of the street, or follow painted guide lines, presumably with computer guidance. It would be electrically powered, and travel at about 30 miles per hour. Its cost of construction, according to designers, is less than one-fifth that of a subway, and could be completed in a year. Song has estimated that the straddling bus can replace 40 buses. The concept was initially promoted back in 2010 by Song’s company, Shenzhen Huashi Future Parking Equipment. But after promises of an imminent pilot project in Beijing, enthusiasm reportedly waned under scrutiny. Aside from potentially being pretty terrifying to drive under, there’s at least one obvious problem with the concept: It seems it would be a serious challenge to prevent the huge moving structure from interfering with cars turning, changing lanes, or entering and leaving the roadway. For more on cities and tech, watch our video. As Treehugger points out, the straddling bus concept is not entirely novel. The so-called “Bos-Wash Landliner” was imagined in the late 1960s as running on air skis (a little like the initial Hyperloop proposal), vacuuming up moving vehicles at 60 miles an hour, and housing everything from a 100 seat theater to a gym. Compared to that, at least, the Chinese proposal is downright sober.