Allowing delivery drivers to reserve curb space significantly cuts the number who double-park or block bike lanes and crosswalks, according to a study of a three-month pilot program in the District.

In August, the city became the first test case for curbFlow, a San Francisco start-up whose app allows delivery drivers to reserve curb space. The test was conducted in nine zones in the city, including Georgetown, Capitol Hill and Southwest D.C.

Between Aug. 1 and Oct. 30, curbFlow’s study found the number of vehicles double-parked in the zones dropped 64 percent, including in areas where vehicles had previously blocked bike lanes and crosswalks.

The findings come as D.C. and other cities work to make some of their most valuable real estate — curb space — more efficient and safer amid an explosion in online shopping deliveries, Uber and other ride-hailing trips, and on-demand restaurant deliveries. City officials say they want to decrease the number of delivery drivers who add to traffic and air pollution by circling the block and create safety hazards for pedestrians, cyclists and other motorists who must swerve around them when they double-park.

Jeff Marootian, director of the District Department of Transportation, said he was “very encouraged” by the company’s findings, particularly the drop in double-parked vehicles.

“We’re doing everything we can to rethink and reimagine how our infrastructure works,” Marootian said. “We know we’ve got more pressure on our curbside than ever before.”

The reservation system, he said, “lessened confusion and created more order at the curbside.”

Now that the curbFlow experiment has ended, Marootian said, city officials will continue to explore other ways to better manage curb space. The curbFlow system was dismantled Oct. 30, and the city has no continuing relationship with the company.

“We know there are new and emerging technologies that can help us better manage our system,” Marootian said. “We want to open up and encourage as much innovation as possible.”

The District created the temporary delivery zones by converting parking spaces, which were restored after the program ended. The program was free for both motorists and the city. Ride-hailing companies and taxis were not eligible to register or officially use the zones, but were allowed to do so and were included in the data, curbFlow said.

CurbFlow founder Ali Vahabzadeh said more than 6,350 drivers registered for the system, and more than 15,500 vehicles used the zones, including most who had not made a reservation. He said a company survey found that 85 percent of users rated the system a 9 or 10 as something they would recommend.

“It validated our hypothesis . . . that if the community accommodates [curb] space for commercial deliveries or on-demand pickups, drivers will use the space and generally do the right thing,” Vahabzadeh said.

Frequent users of the system provided by curbFlow said the zones sped up deliveries and cut back on costly parking tickets.

Wayne Saunders, a contract driver for Rapid Response delivery service, said he regularly used the Georgetown zone to make deliveries to a shoe store on Wisconsin Avenue.

“I could pull up right to the store, make my delivery and go on about my day,” Saunders said.

After the pilot ended, Saunders said he recently had to park two blocks away. That turned what had been a 10-minute delivery into 30 to 45 minutes of schlepping shoes via several trips with a dolly.

“I had to circle the block four to five times and then bring the shoes up a hill and walk the whole way up so I wouldn’t get a ticket,” Saunders said.

Jesse Jones, who delivers 20 to 30 pizzas daily for We, The Pizza on Capitol Hill, said he used the curbFlow zones 15 to 20 times a day, particularly one near his restaurant when he needed to load fresh pizzas.

“It was a lifesaver,” Jones said. “It saved me hundreds of dollars” in parking tickets.

Since the program ended, Jones said, he often has to double park, even though he worries about the cyclists and scooter riders who must swerve into traffic to get around him.

“I don’t want to put people in harm’s way,” Jones said.

Steve Moore, executive director of the Southwest Business Improvement District, said he’s “thrilled” the city is exploring better ways to manage curb space, including in heavily congested areas like the Wharf. He said he was impressed with the study’s findings that the reserved zones cut down on double-parking and vehicles making unsafe U-turns — something he hopes the city will continue to explore with longer-term testing.

“We knew we needed a version of an air traffic controller” at the curb, Moore said. “This was something we were dying to try.”

CurbFlow is scheduled to launch a 12-month pilot project in Columbus, Ohio, on Monday, and Vahabzadeh said he expects to launch in four more cities in a few months.

Unlike in the D.C. experiment, Columbus customers will have to pay. Vahabzadeh declined to disclose the cost but said, “We’re talking dimes and quarters here, not dollars.”

He said he expects delivery companies that can incur “millions of dollars” in annual parking fines will welcome the chance to pay less for legal parking.