Update Sept. 14, 2017: The city of Portland has concluded its investigation into Uber's use of a software tool called "Greyball," Portland commissioner Dan Saltzman announced Thursday.

Greyball was used by ride-hailing company Uber to evade city regulators and deny service to some customers. Saltzman said the investigation uncovered the extent to which Uber utilized the evasion tool, but the city is sure Uber will not attempt to evade regulators or deny service in the future.

Read the full report here

Uber did not receive any formal punishment or restrictions from the city.

Saltzman said transportation network companies like Uber are valuable to Portlanders, and both Uber and the city are strengthening policies to prohibit such practices. He released the following statement:

“Uber has complied with our subpoena and provided the requested information associated with the Greyball tool,” said Commissioner Dan Saltzman, who oversees the Portland Bureau of Transportation. “Through this subpoena process, we have a greater understanding of their activities in Portland, and the extent to which the Greyball tool was used here. Moving forward, we have ensured that no attempts to evade regulators or deny service to riders in violation of City code or law will be allowed in the future.”

Original story published May 5, 2017:

PORTLAND, Ore. -- Portland Commissioner Dan Saltzman is asking the city council to subpoena Uber in the latest dispute between Portland and the ride hailing service.

At the center of the conflict is the software tool “Greyball” that allegedly helped Uber evade regulators in cities around the world.

Saltzman announced that he was seeking the subpoena next week to learn more about how Greyball was used.

Background: Portland launches investigation into Uber's 'Greyball' tool

Portland Bureau of Transportation officials say the tool helped Uber identify which potential riders were customers and which ones were undercover city regulators when the company illegally entered the Portland market in December 2014.

PBOT alleges Greyball tagged 17 individual rider accounts, 16 of which belonged to government officials, and Uber drivers would then refuse to pick up those riders.

Uber spokesman Bryce Bennett said Friday that out of those 17 accounts, only three users actually requested rides. He added that Uber shared the Greyball info with PBOT in the interest of transparency moving forward.

Bennett released the following statement:

"While we are reviewing the full content of the report, we remain proud of having brought greater access to affordable, reliable transportation to riders in all areas of Portland, and flexible earning opportunities to thousands of drivers. Throughout the investigation, we have been forthcoming with the city. Specifically, we provided details about the use of the “Greyball” technology in Portland, which was confined to the accounts of 17 individual Uber riders for approximately two-weeks in December 2014. Only three of those individuals sought to request an Uber ride during that period. By sharing this detailed, specific information with PBOT, our intent was to provide the most relevant and helpful data for understanding the extent of this activity in Portland.

"It is unfortunate this investigation and the report have become so politically charged, and that Commissioner Fish has used the process to make baseless claims about our conduct in Portland. As PBOT data has shown, Uber has in fact increased access to reliable, affordable transportation in all areas of the city, including East Portland. As of March of this year, there are more than 6,000 active Uber drivers and more than 325,000 riders in the greater Portland metro area. We plan to continue serving drivers, the city, and its residents and visitors."

Saltzman said Friday he was also concerned that Uber may have used to Greyball to discriminate against potential riders based on income, though there has been no evidence to support that claim. But Saltzman said the subpoena could help prove the practice did not happen.

Uber has paid $67,000 in fines to the city of Portland for its illegal operations during that two-week period in December 2014.

PBOT officials said Friday there’s no evidence Uber continued to use Greyball or any similar evasion tool after April 2015, when the city first granted the company permission to operate as part of a pilot program.

Read PBOT's Greyball audit report

Greyball Audit Report by KGW News on Scribd