Princes Street is to close to all traffic for six months next year while Edinburgh's tram tracks are laid (link below.)
http://news.bbc.co.uk/1/hi/scotland/edinburgh_and_east/7364445.stm

Transport Initiatives Edinburgh (Tie) confirmed hundreds of buses a day will be forced to use an alternative route along George Street from January 2009.

The cost of building line 1a, which will run from Newhaven to Edinburgh Airport, has also risen by £10m to £508m, it has been revealed.

Tie said the rise was due to the fall in the pound's value against the Euro.

The tram infrastructure work, to be carried out by Bilfinger Berger Siemens (BBS), will start on 1 June. Construction is due to finish on 17 January 2011.

Trams are not due to be running on line 1a, often referred to as "Edinburgh's backbone", until 3 May 2011.

A spur from Haymarket to Granton, known as line 1b, was put on hold when the tram plans were scaled back in 2006 amid fears that costs were spiralling out of control.

Tie has now announced it is "committing" to line 1b.

Line 1a will have 11 miles (18km) of track, nine substations to power the trams, 22 tram stops and a single depot at Gogar.

Phase 1b would have almost 4 miles (6km) of track, three substations and nine tram stops.

Rob Winter, of the Princes Street Traders Association, said retailers had been aware of a possible closure and had expressed concern about how deliveries would be made to major stores on Princes Street without loading bays at the rear of their premises.

The contract will see an extension of the hours of working for contractors from 0700 BST to 1900 BST Monday to Saturday in response to the wishes of Edinburgh's business community.