Phase two - opened on Thursday - is the longest section of the road, crossing the Clyde at Rutherglen Bridge and passing Dalmarnock Railway Station, the Commonwealth Arena and Celtic Park before joining the Parkhead by-pass at the Forge Retail Park.
When new bus lanes opened in May Street in September, under the first phase of Belfast on the Move, motorists and city centre retailers complained of severe traffic jams during the rush hour.
Dray Horse Yard, which includes a multiplex cinema and restaurants, was opened at the site in October last year as part of the project's current phase two.