The scenes are straight out of a Jules Verne novel or the 1960s cult cartoon "The Jetsons."

Driverless cars streak down the Stevenson Expressway, traveling in platoons for reduced wind resistance, while old-fashioned cars (the kind with people at the wheel) are consigned to a 65 mph slow lane.

Glassy passenger pods float above a Manhattan street, which has been transformed from an anonymous stretch of asphalt into a welcoming swath of trees, grasses and walking paths.

Idle speculation? No.

A rendering shows how driverless cars could lead to a transformation of city streets
A rendering shows how driverless cars could lead to a transformation of city streets - In this case, a stretch of Chicago's Martin Luther King Drive. The road's wide stretches of asphalt would be replaced by thin strands of porous paved surface (shown here in white) that would accommodate driverless vehicles. New plazas and greenery would break down the traditional barrier between the sidewalk and the street. At lower right is the Harold Washington Cultural Center, 4701 S. Martin Luther King Drive © The Driverless City Project/Illinois Institute of Technology

Even if these visions don't wind up forecasting the future with pinpoint accuracy, they give us a glimpse of something important: Architects and urban designers, including those in Chicago, have started shaping bold new city planning ideas to prepare for the coming era of the self-driving car.

These designers view driverless cars not simply as a new transportation technology, but as a kind of liberating agent that would free vast stretches of cities from the one-dimensional role forced on them in the auto age.

The possibilities are dazzling. If self-driving cars lead to a significant drop in the number of vehicles on the road, parking garages could be turned into apartments or stores. Curbside parking could be converted into rainwater-collecting bio swales that help prevent sewers from backing up. Roads would narrow. Sidewalks would widen.

More people would use trains because driverless cars would pick them up and finish the "last mile" of their journey. The remaining parking garages will be able to accommodate up to three times as many vehicles because driverless cars would be able to maneuver far more reliably than cars controlled by humans.

That, at least, is the utopian scenario, which also foresees self-driving cars giving the elderly, the disabled and maybe even children new opportunities to get around.

There is also a dystopian alternative offered by futurists who paint a picture of technology run amok: If autonomous vehicles dramatically lower driving costs and give people a new incentive to take to the road, streets could be overwhelmed. Suburban sprawl would increase rapidly as high-speed driverless cars cut commute times and make it profitable for builders to construct new subdivisions in distant exurbs.

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