A long-awaited traffic study has found that Uber and other car-hailing services haven’t significantly added to Manhattan’s increasingly congested streets, people familiar with the matter said on Thursday. “It does not point the finger at Uber,” said a person briefed on its findings who works in the taxi and for-hire car-services industry. The study, expected to be released in the coming days, was prompted by a fight last summer between Uber and New York City Mayor Bill de Blasio, when he proposed capping the growth of the city’s for-hire vehicle fleet.