A combination of diversions and motorists avoiding the area meant traffic did keep moving during both the morning and evening rush hours.
At around 5pm traffic was reported to be "light" on Lothian Road and throughout the rest of the diversion routes.
From as early as 7am cars and buses diverted from the West End down Melville Place were snaking back the length of the street to Manor Place and beyond.
And Lothian Road and the West Approach Road were also clogged with traffic as drivers got used to the new temporary road layout.
Shandwick Place is now closed for five months as part of the tram works, with a series of major road diversions put in place.
All traffic travelling west from Princes Street is being directed up Lothian Road and on to the West Approach Road, while cars and buses heading from Haymarket towards the city centre are going along Melville Street.
Bus firms today reported problems on Saturday, the first day of diversions, but said things were running relatively smoothly.
Special police motorbike patrols on the diversion routes are in operation to keep them clear.
Tram chiefs said the traffic was flowing as planned and thanked drivers for their patience.
Changes to the bus routes got underway on Saturday while the remaining barriers and signs needed for the diversions were put in place over Sunday.
Delays across the city were compounded by ongoing gas mains replacement works on Slateford Road and Clerk Street.
Both works added to frustration among commuters.
Kate Toft, 28, a language therapist at the Royal Infirmary was waiting for her bus at the bus stop on the packed Melville Street at around quarter past eight. She said: "I haven't left for work any earlier than normal this morning as I'm just going to wait and see how it goes."
Her bus arrived on time but she was not optimistic that her good luck would continue.
"I'd imagine it's going to get pretty bad," she added with a shrug. "It is Edinburgh after all, the traffic's bad without roadworks."
Jamie Macdonald, 29, a researcher who lives on Easter Road, has to negotiate Leith Walk and Queen Street on his drive to work in Clackmannanshire, said: "These past few months have been a nightmare and all this starting today is only going to make it even worse."
The 19-week closure of Shandwick Place involves temporarily removing parking on Melville Street to accommodate the extra traffic from the eastbound diversion.
Buses are going around Charlotte Square, with some services going along George Street, while all other traffic is being diverted along Queensferry Street and Randolph Crescent to join up with Queen Street.
There will also be work on Princes Street from Frederick Street westwards and telecoms diversionary work in St Andrew Square in the coming months.
This phase of the project is scheduled to be completed by the start of the Edinburgh Festival in August.
Iain Coupar, marketing director for Lothian Buses, said: "We have people on the ground as well as access to all the cameras and everything seems to be going relatively smoothly.
"On Saturday there were a few issues, particularly with the syncing of traffic lights and this caused delays.
"However, Siemens, the traffic light contractor, have been out and adjusted them and everything on Sunday, which is a quiet day anyway, went smoothly."
Thirteen bus stops are closed on and around Shandwick Place and have been replaced by 12 temporary stops dotted along the diversion routes. A further 11 stops in the city centre have had their normal services changed.
A total of 136 parking spaces have been lost, mainly on Melville Street, as a result of the diversions.
Graeme Barclay, TIE construction director, said the first morning had passed off smoothly because of a mix of the traffic management arrangements and people making alternative arrangements: "TIE is constantly monitoring the traffic situation and we are pleased that the early stages are flowing as planned.
"We well continue to monitor the traffic as works continue but we do appreciate the ongoing patience and co-operation of drivers."
The full programme of tram roadworks will take more than three years to complete and involves digging up the roads twice – first to move water and gas pipes then to build the tram lines, stops and overhead wires.
The underground pipes and cables are being moved so they can be accessed without disrupting trams, which are due to start running between Edinburgh and its airport in three years' time.
A police spokesman said: "We had the patrols over the weekend and there wasn't any problems and so far things have also gone well."
Commuters in Leith Walk have already been given a flavour of the sort of disruption seen elsewhere in the city today over the last six months.
Since August, the road has been the subject of lane closures and lengthy tailbacks at rush-hour as utility diversion works got under way on the busy street.
Details of the remaining tram disruption, which is likely to include a complete temporary closure of Princes Street, and the final design of the tram route, are set to be released in April – two months later than planned.
It is likely that George Street will bear the brunt of any traffic diverted away from Princes Street and this is likely to need the temporary removal of some of the street's historic statues such as George IV and William Pitt.
Bruce Young, Lothian and Borders co-ordinator of the Association of British Drivers, said: "It is very likely that given what a nightmare this is going to be people are trying to avoid the area.
"There is no way all that volume of traffic can be handled on the diversions so people will be looking for alternative routes.
"Many commuters have a limited choice on the way they travel to work so I think many people will be looking at taking other roads such as Queensferry Road as a way of avoiding the West End."
NEW road priorities on Lothian Road have been set out with cones after many drivers were confused before the city centre diversions even got under way.
Drivers told the Evening News on Saturday they were left flummoxed as the flow of traffic unexpectedly changed from north to southbound. Painters made the changes on Lothian Road's central lane on Thursday but no road signs were put up to show a change in priorities.
The confusion was rectified over the weekend after the News contacted trams firm TIE.