Uber, Lyft, and other app-based ride-hail businesses aren't entirely responsible for Manhattan's notoriously congested streets, a hotly anticipated city-backed study will say when it's released today, according to The Wall Street Journal.

If the $2 million traffic study does not implicate any of the fast-growing ride-hail apps, the study could represent the final death knell of New York City Mayor Bill de Blasio's effort to regulate Uber and its competitors. Last summer, the mayor announced a plan to pause Uber's growth, arguing the spike in the number of cars on the road affiliated with the San Francisco-based startup and its rivals was worsening congestion and responsible for noticeable declines in traffic speeds in Manhattan's central business district.

The New York City Council still has Uber in its crosshairs

The plan sparked a vicious fight between the mayor, who has received large donations from the city's traditional yellow taxi industry, and the deep-pocketed, politically pugnacious ride-hail app. Uber poured millions into a negative ad campaign, which portrayed de Blasio's plan as racist. Ultimately, the mayor pulled back his plan, agreeing with the City Council to conduct a four-month-long study on Uber's effects on traffic.

According to the Journal, the study, which was conducted by consulting firm McKinsey and Company and former traffic commissioner Bruce Schaller, will note that Uber and Lyft have contributed to an explosion in the number of for-hire vehicles, but that there was no correlation to slower traffic speeds.

Indeed, the number of Uber drivers on the road has increased exponentially over the last year. Last September, 10,000 uberX drivers, which operate as black cars, were roaming the streets of New York City. By March 2015, about 13,000 car-service drivers were using Uber's app to arrange rides with passengers. By September, that number had grown to 20,000, as well as another 4,000 yellow- and green-cab drivers who could be hailed through the app's uberT feature. Taken together with the company's limo, SUV, and carpool services, there are now over 30,000 Uber-affiliated vehicles in New York City.

The council, which is comprised of mostly liberal Democrats who are skeptical of gig economy businesses like Uber and Airbnb, is already taking its own steps to impose new rules on those darlings of Silicon Valley. A slate of bills that would require Uber to make its cars more accessible to disabled passengers, pay a surcharge for public transportation, and cap surge pricing are all under consideration.

Update January 15th, 2:35PM ET: The de Blasio administration finally released the report Friday afternoon, and as predicted, it exonerates Uber and Lyft for all traffic-related crimes. ​

Here's the key paragraph:

Vehicles of all types play a role in congestion in the [central business district]. The number of trips by all vehicle types in the CBD remained flat between 2014 and 2015 as increases in transit ridership offset increases in trip demand driven by growth. Increases in e-dispatch trips are largely substituting for yellow taxi trips in the CBD. Because these e-dispatch trips are substitutions and not new trips, they are not increasing [vehicle miles traveled].

In other words, because more people are riding with Uber than yellow taxis, the ride-hail app cannot be said to be contributing to worsening traffic conditions in Manhattan's central business district.

Update January 15th, 3:30PM ET: Josh Mohrer, general manager of Uber in New York City, released a statement thanking the mayor for the report:

"We appreciate the thoughtful process Mayor de Blasio and his administration have engaged in over the last several months to improve the commercial car industry. We also want to thank Speaker Melissa Mark-Viverito and the City Council for working with stakeholders throughout this process. We are supportive of several of the proposals presented today, especially efforts to empower drivers by giving them more freedom to partner with companies across the industry. We will be reviewing the policy ideas and hope to work with the de Blasio administration and the City Council on implementing many of them."

For Hire Vehicle Transportation Study