Urban design experts at the University of Minnesota are redrawing what city blocks could look like in a world of driverless vehicles.

Roads of the future will likely be narrower, greener and easier to share with pedestrians once autonomous vehicles evolve from the drawing boards and testing roads of automakers and tech firms to widespread use on city streets.

The move to wrest the controls from human drivers is gaining traction. The U has just received a $1.75 million grant from the National Science Foundation to further study autonomous vehicles and the future of transportation services. State agencies are testing the technology, and Minneapolis and St. Paul city officials are factoring in the potential impact of autonomous vehicles as they draft plans to guide development over the next two decades.

This summer, researchers at the U's Minnesota Design Center focused on locations like the intersection of Lexington Parkway and Marshall Avenue in St. Paul and the parking lot for the Kmart store on Lake Street in Minneapolis as they explore the impact autonomous vehicles could have on street design in the Twin Cities.

Already, researchers see big potential in an anticipated ability of autonomous vehicles to follow more precise paths, allowing roads to be much narrower, freeing up land for other purposes. Car sharing may increase, allowing back alleys to be redeveloped into pocket parks. Parking lots could become wetlands or ponds.

"You can start to do other things in the street like literally have picnic tables or community gardens or playgrounds, things you wouldn't even imagine putting next to a street or public right of way is now possible," said Thomas Fisher, director of the Minnesota Design Center and one of the lead researchers for the Shared Autonomous Vehicle Street Design study.

Fully autonomous vehicles are expected to be available to consumers by 2025, according to a study by the National League of Cities.

In August, the Kroger supermarket chain started a grocery delivery pilot program with a robotic vehicle in the Phoenix area. Earlier in the summer, Waymo, formerly Google's self-driving car project, announced a pilot to transport customers to Walmart stores. Japanese automaker Toyota recently invested $500 million into ride-sharing company Uber to accelerate its self-driving program.

The technology is far from foolproof. Uber earlier this year pulled back on driverless testing in Arizona after an autonomous Uber vehicle struck and killed a woman who was pushing her bike across a dark street in Tempe.

But accidents aside, technological developments and planning continue.

A draft of the 2040 Comprehensive plan for Minneapolis includes action steps for the city to plan for the impact of automated and connected vehicles. A similar effort in St. Paul also references a goal to ensure that right-of-way design accounts for automated vehicles and other innovations.

In March of this year, Gov. Mark Dayton established an advisory council on connected and automated vehicles and ordered the Minnesota Department of Transportation (MnDOT), Department of Public Safety and other agencies to create programs and guidelines for developing, testing and deploying automated vehicles.

3M Co., a big player in transportation safety technology, is among the members of the advisory council.

"We believe in the promise of autonomous vehicles to make our roadways safer and, eventually, to make transportation more efficient," said Andrew Dubner, business manager of 3M's Connected Roads Program, in a statement to the Star Tribune. "Ultimately, the future of automated driving is about an integrated ecosystem to help keep drivers and non-drivers safe. Urban planning plays a big role, together with allowing cars to communicate with each other and with road infrastructure."

Last winter, MnDOT tested an autonomous shuttle bus to see how it responded to cold-weather conditions. Among the conclusions noted by researchers in a June report was that the shuttle's wheels did not wander much on multiple trips.

These predictable paths mean driverless vehicles don't need as much space on the road, said Fisher. "That allows the rest of the surface of the street to be what we call pervious surface, which could be grass or gravel or ground cover or what have you, which then also allows water instead of water having to be shed to gutters and curbs and storm sewers," Fisher said.

Joe Favour, head of the landscape architecture department at the U and one of the researchers, envisions rain gardens and playgrounds in what were once busy streets.

"We wouldn't be designing this as much for vehicles as we would for people and bikes," Favour said. "It changes the philosophy."

The U researchers' design renderings show that by 2050, when autonomous cars could be more mainstream, Lexington Parkway and Marshall Avenue in St. Paul could narrow considerably. Instead of the current multiple traffic lanes, the streets could feature two 8-foot-wide lanes going in opposite directions.

With many people possibly opting to subscribe to mobility services with autonomous vehicles instead of owning their own cars, residential back alleys could also be suffused with green space.

In images of the crossing of Cleveland and Marshall avenues in the Merriam Park neighborhood, researchers re-imagine a liquor store parking lot as playing fields and a farmers market extending into space that presently is part of the street.

But the concept has its issues.

It could cost a considerable amount of money for cities to transform their streets, Favour said. Who would maintain and continue to pay for the maintenance? Would the cost savings for the stormwater mitigation cover the costs of maintenance? How would snow be removed?

Peter Bruce, a local pedestrian studies consultant, said the designs the U came up with included attractive features, however, he questioned their practicality during the winter months.

"Colorful, green, artsy surfaces [natural or man-made] are great beacons for luring people to walk along the street," he said in an e-mail. "We just have to make sure we can maintain them."

Nicole Norfleet • 612-673-4495

Twitter: @nicolenorfleet