Car traffic was banned from 4 to 10 p.m. on Main Street between South Temple and 200 South.
Businesses were encouraged to set up sidewalk sales, and area bands and "buskers," or street performers, were on hand to entertain passersby.
Jason Mathis, executive director for Downtown Alliance, said the unadvertised event was designed to be super-casual, "to see what the street might feel like if it were a pedestrian thoroughfare.
"We said we'd bring the party," Mathis said.
Utah Transit Authority TRAX trains continued to run as usual through the area, and the traffic signals cycled in normal fashion.
UTA's Gerry Carpenter said extra transit police and personnel were on hand, along with additional Salt Lake City police officers.
Carpenter said the trains don't go fast in that area because they are approaching platforms, but security personnel were on heightened alert. People also were encouraged not to loiter or stand in the railroad right-of-way, he said.
Cities such as Portland, Ore., with its people-friendly streetcar system, have grown accustomed to mixing foot traffic with transit, Raymond noted.
"We're dipping our toes in the water. Any regular user of Main Street knows it's not a very car-friendly street and not a good way to get from point A to point B," Raymond said. "It's definitely worth exploring as a possible pedestrian-specific thoroughfare in the future."